RBMHHB THE CLAY RESOURCES AND THE CERAMIC INDUSTRY OF CALIFORNIA BY WALDEMAR FENN DIETRICH BULLETIN No, 99 ISSUED BY THE CALIFORNIA STATE MINING BUREi^n FERRY BUiLDLNG. SAN FRANCISCO 1928 l tfUlJMHW W W fW^a**^V V W. M.dium to high strength 338 IV. Clays liiirning dirty white, cream white or yellowish white 348 17. Cenorally contain calcium or magnesium carbonate 348 Chemical analyses 353 Index of clay sample numbers 357 Index of clay samples, by counties 358 General index - 362 LIST OF TABLES. No. Title rage 1. Check list of ceramic plants In California 22- 25 — 2. Brick and hollow tile production for llt26, l)y counties 32 .'). Common brick production (jf California, l).v years 33 4. Production of pottery clay in California in 1926 33 5. Pottery clay production of California, l>y years 34 6. Value of pottery clay products made in California during l!t2i) 34 7. California and total United States production of ceramic products from 1896 to 192C 36 8. Description of core drill samples from lone district 52 !t. End points of Orton pyrometric cones m Centigrade and Fahrenheit degrees. 244 10. Visual correlation of certain Ridgway colors with Munsell colors 251 11. Key to classification of clay samples tested 258 12. Drying data, clays of classes 1 and 2 267 13. Firing data, clays of classes 1 and 2 268 14. Drying data, clays of classes 3 and 4 274 15. Firing data, clays of classes 3 and 4 275 Hi. Drying data, clays of class 5 283 17. Firing data, clays of class 5 284 18. Drying data, clays of class 6 293 19. Firing data, clays of class 6 294 20. Drying data, clays of classes 7 and 8 306 21. Firing data, clays of classes 7 and 8 307 22. Drving data, clays of classes 9, 10 and 11 317 23. Firing data, clays of clas.ses 9, 10 and 11 318 24. Drying data, clays of clas.ses 12 and 13 ^''Q 25. Firing data, clays of classes 12 and 13 33i 26. Drying data, clays of classes 14 and 15 : 344 27. Firing data, clays of classes 14 and 15 345 28. Drying data, clays of cla.ss 17 350 29. Firing data, clays of class 17 351 30. Chemical analyses of clays from sampled deposits 354-355 31. Chemical analyses of miscellaneous California clays, not sampled 356 LIST OF PLATES. No. Title Page I. Map showing locations of high-grade clay deposits in California IS II. Common brick and cement statistics of California 33 TIT. Annual value of clay jiroducts in California and in the United States 37 IV. Map of Tesla district, Alameda County 43 V. Ceologic section through main Tesla shaft 44 VI. Property map of If)ne district, Amador County 50 VIT. Sketch mai) of Clark and Marsh kaolin mine near Calistoga 134 VIII. (ieneral arrangement of (piarry and plant of the Clay Corporation of Cali- fornia, Lincoln, Placer County 148 IX. Vertical section of clay beds on Clay Corporation of California's jiroperty, near Lincoln 149 X. Property map of Alberhill-Corona district. Riverside County 162 XT. Diagrammatic section of strata at Alberhill 163 XII. Handling and storage of clay by the "glory-hole" method 168 LIST OF PHOTOS. No. Title Page 1. Russ Building, San Francisco Frontispiece 2. Ryan Ranch clay deposit 46 3. Filter-press room, Westinghouse Electric and Manufacturing Company 47 4. Hot-pressing room, Westinghouse Electric and Manufacturing Company 48 b CONTENTS Page 5. Gage clay pit 53 6. Jones Butte Mine 54 7. Barber or Shepard pit 55 8. Sand Pit subleased by the lone Fire Brick Company 55 9. Yaru clay pit 56 10-A. Fancher clay pit 59 10-B. Brick machinery in plant of lone Fire Brick Company 60 10-C. Sand pit of the lone Fire Brick Company 62 11. Valley Springs clay pit 69 12. California Art Tile Company's ijlant 72 13. Richmond Pressed Brick Company's plant 75 14. Plant of Thompson Brick Company 82 15. Vitrefrax cvanite deposit 86 16. Malibu Pottery 106 17. Drying floor, Los Nietos plant of Pacific Clay Products Company 108 18. Airplane view, Lincoln Heights plant, Pacific Clay Products Comjjany 110 19. Airplane view, Los Nietos plant, Pacific Clay Products Company 112 20. Clay bins and unloading crane, Lincoln Heights plant. Pacific Clay Products Company, Los Angeles 113 21. Pug-mill, auger machine and cutter, Lincoln Heights plant. Pacific Clay Products Company, Los Angeles 114 22. Dry pans and twin wet pans, Los Nietos plant, Pacific Clay Products Com- pany, Los Angeles County 115 23. Sewer-pipe press, Los Nietos plant. Pacific Clay Products Company 116 24. Interior view of plant, Vitrefrax Company, Los Angeles ^ opp. 122 25. California MuUite brick being fired in tunnel kiln at cone 28, Vitre'rax Com- pany, Los Angeles 122 26. Clay and shale deposit of McNear Brick Company, showing loading hopp r, Marin County 125 27. Clark and Marsh Kaolin Mine 133 28. Flint fireclay at portal of tunnel. Goat Ranch, Gladding, McBean and Com- pany, Orange County 142 29. M M 2 pit. Goat Ranch, Gladding, McBean and Company, Orange County 143 30. Plant of La Bolsa Tile Company, Weibling, Orange County 143 31. Vitrefrax Company, entrance to upper chamber workings, O'Neill Ranch clay deposit. Orange County 145 32. End-cut during preparation of pit of Clay Corporation of California, Lincoln, Placer County 150 33. Clay pit of Gladding, McBean and Company at Lincoln, Placer County 152 34. Airplane view of Gladding, McBean and Company plant at Lincoln 154 35. General view of pit and plant, Lincoln Clay Products Company 156 36 "Eastern end of pit, Lincoln Cay Products Cnmiiany ■> '"' ?'«.' Western end of pit, Lincoln Clay Products Company 157 3'S. Valley View Mine, i>ortal of lower tunnel 160 39. Valley View Mine, upper workings 160 40. Southwest wall of main pit, Alberhill Coal and Clay Comn-'ny 164 41. Alberhill Coal and Clay Company, cut connecting main and west pits 165 42. Alberhill Coal and Clay Company, one of the loading trestles 165 43. Lower portion of west pit. Alberhill Coal and Clr>v Company 166 44. Alberhill Coal and Clay Company, exposure of lignite coal 167 45. Emsco Clay Company, Harrington pit 170 46. Loading chute, Emsco Clay Company 172 47. Gladding, McBean and Company. Alberhill. main tunnel pit 174 48. General view of Alberhill plant. Los Angeles Brick Company opp. 176 49. Los Angeles Brick Company, Alberhill plant, during construction 177 50. Los Angeles Brick Company, Alberhill ])lant, timnel driers, during construc- tion 177 51. Los Angeles Brick Company, Alberhill plant, showing drier cars and brick represses 17S 52. East pit, Los Angeles Brick Company, Alberhill 179 53. Douglas pit. Pacific Clay Products Comi)any at All>erhill 180 .')4. Cannon and Company's plant, Ben Ali 184 55. Electric shovel in preliminary cut, Natoma Cay Company 187 56. Panama Pottery Comiiany's plant, near Sacramento 187 57. Fancy garden pottery, manufactured by Panama Pottery Company 188 58. H. F. Coors Kaolin Deposit. Hart. San Bt^rnardino County 194 59. Pacific Kaolin Mine, Standard Sanitary Company, upper workings 196 60. Pacific Kaolin Mine, Standard Sanitary Comnanv. lower tnnn-'l leve' 197 61. "Bear Cat" shovel at Kelly No. 1 mine. Pacific Clay Products Company, Farr siding, San Diego County 204 62. Wiro Mine, fireclay denosit east of Cardiff, San Diego County 205 63. Plant of the Stockton Fire Brick Company. Stockton 210 64. Clay bins and dry pans in plant of Stockton Fire Brick Company 211 65. Plant of San T^uis Brick Works San Tjuis Obisno 214 66. M'eiss clay deposit, near Glen Ellen. Sonoma County 228 67. Assay laboratory, Stanford University 242 68. Fisk pre-mi.x gas-fired laboratorv kiln, in ceramic laboratory, Stanford Uni- versity 243 69. Wilson oxy-acetylene cone fusion furnace in ceramic laborator.v, Stanford University 247 70. Cabinet of fired test pieces, ceramic lalioratory, Stanford University opp. 257 LETTER OF TRANSMITTAL. To His Excellencij, Hon. C. C. Young, Governar of the State of Calif onvia. Sir: I have the honor to herewith transmit bulletin No. 99 of the State Division of Mines and Mining on the Clay Resources of California. This work deals in detail with one of California's nonmetallic mineral ijidustries which is annually growinp' in importance and value. Ceramic plants are being established in increasing numbers, existing plants are lieing enlarged, and a wide variety of products is being put on the market. Our natural deposits of clays in this state form the basis upon which these industries are founded. This bulletin is the result of over two years' field and laboratory investigations conducted by Mr. W. F. Dietrich, associate professor of mining engineering at Stanford University; the work being handled on a cooperative basis between the University and this Division. Acknowledgement is here maile of the courtesy aud cooperatiou of Mr. Theodore J. Hoover, Dean of the School of Engineering of Stanford University. Respect fully submitted. Lloyd L. Root, State iMineralogist. CHAPTKK I. IXTRODUCTIOX. The scope of this rei)()rt is confined to a study of the raw materials and manufacturinji' practice of tiiat part of the ceramic industry of California wliich involves the manufacture of products which "are molded in the aqueous plastic condition and which derive their strength from the iiartial fusion (vitrification) of silicates at hig'h temjiera- tures. "^ This restriction excludes ylass, enameled metals, cements, limes, l)lasters, and most abrasives, whicli in modei'n parlance are broadly considered to belong to tlie field of ceramics. The report inchules a brief technical description of most of the clay- working plants and known clay deposits in California, together with the results of laboratory tests of the important clays of the state.. The l)rincipal emphasis is upon the economic and technologic phases of the clay-working industry of California, rather tlian ui)on its geologic aspects. The field work was done in the summers of 1925 and 1926, and the total time in the field was five months. In a state luiving 155,652 s([uai-c miles of land area, it was obviously impossible in the period of tile field examination to make detailed investigations of all known clay deposits, or to search for new^ deposits not already known to the ceramic industry, the Mining Bureau, or to local inhabitants in the possible clay areas. Hence the principal value of this report lies in the fact that it is a record of progress of the clay industry and presents for the first time standard test data on the known clays as a basis of comparison for new clays that may be discovered in the future. The uses of many of the clays that were tested are very well known from i^lant experience, so that it should not be difficult for the intelligent plant operator to correlate the test data with the results of commercial practice, not only for the clays now in use in his i)lant, but for other clays that have been tested. The search for high-grade clays on the Pacifie coast has received new impetus in recent years on account of the phenomenal increase in ])opulation in the region and the consequent increased demand for structural and decorative clay products. There seems little doubt that this is but the beginning of one of the greatest ])eriods of exjiansion that the world has ever seen. If this vie-\v of the future is correct, California is destined to become one of the great ceramic centers of the United States. That new clay deposits will be discovered is almost a foregone conclusion. Thus far, only the obvious deposits have been found, and only those that can be cheaply mined, and that can be used without beneficiation, have been exploited. The geologic column of California is practically complete, and there remain many thousands of square miles of land that have never been tlioroughly ])rospected for clays. Prospectors and local residents away from existing clay pro- ducing regions are on the whole unfamiliar with the nature of clays, but it is certain that their knowledge Avill improve by contact with trained men who are on the lookout for new discoveries. It is true that the abundance of cheaply recoverable terra cotta and fire clays has 1 Wil.son, Hewitt, Ceramics, p. 2, McGraw-Hill Book Co., 1927. 12 DIVISION OF MINES AND MINING heretofore hindered the development of iieAV resources, but with the rapid acquisition of the best of these deposits by single manufacturing interests, and Avitli the increasing demand for new types of clays, either to displace those varieties now being imported from outside of the state, or to make improved products, the incentive to clay prospecting will be entirely adequate. METHODS OF INVESTIGATION. The field work on the clay depositvS consisted of a visit to each prop- erty to obtain clay samples and to prepare a description of the develop- ment and mining operations, tlie thickness of the clay and overburden and other features of i^ossible interest. ]Most of the samples were taken from exposed surfaces, and due precautions were taken to secure sam- ples that were representative of the workable beds of clay. In a few places, samples were taken from bins or storage piles, if these seemed more suitable for securing representative samples than the clay banks. In some instances, samples were submitted by the clay producers them- selves as being representative of their deposits. A number of core drill samples were obtained from the lone district, through the courtesy of S. E. Kieffer. The plant descriptions were nearly all prepared by the author after an inspection of the plant. Many of these descriptions were submitted to the plant executive for approval before publication. A few descrip- tions were prepared by members of the organization concerned. Descriptions of a number of plants that were started subsequent to the field investigation or that were overlooked by the author, Avere pre- pared by ^Messrs. Laizure, Logan, or Tucker, district engineers, Division of ]Mines and ^Mining. The test Avork Avas done in the ceramic laboratory of the Department of ^Mining and ^Metallurgy at Stanford University by methods described in Chapter IV. PREVIOUS WORK. The clays and clay industries of California AA-ere described in two earlier reports^ of this Bureau. These reports include descriptions of knoAvn deposits and of the operating plants, but contain very fcAV data on the ceramic properties of the clays. Most of the county reports of the Bureau contain descriptions of clay deposits and clay-Avorking plants that Avere prepared by members of tlie State Mineralogist's staff. In a number of cases these descriptions are sufficiently up to date to permit their use in the present report, and are reprinted here for the sake of completeness and continuity, as the county reports are scattered through a number of volumes of the State Mineralogist's reports. An important article- on the Alberhill clays by the late J. H. Hill, then president of the Alberhill Coal and Clay Company, Avas pub- lished bA' tlu' Bui'eau in 192:^. ' Stiiutural ami Industrial Materials of California: Cal. State Min. Bur., Bulletin 3S, part 111, pp. i;tu-25y, 190G. The Clav Industry in California: Cal." State Min. Bur., Prel. Report No. (, 102 pages, ly20. = Hill, J. H., Clav deposits of the Alberhill Coal and Clay Company: State Miner- alogist's Report XiX, pp. 185-210, 1923. CLAY RESOURCES AND CERAMIC INDUSTRY 13 The foraiuif |)r()i)oitios mid cliemieal analyses of certain clays from tlie Alberliill district liave bi-en jjfiviMi by I>nrclifi('l.' Tlio clay iiiininir and jjropai'atioii plant of tlic Clay Corporation of California, at Lincoln, has been described by C. N. Schuette.- AU of the foregoing references were freely used in the preparation of this bulletin, even at the cost of repetition, as it was desired to bring together in one vohnne all of the avaihd)lc infoi'iiiation on the ('la\' resources of the state. ACKNOWLEDGMENTS. In a work of this nature it is impossible to give individual acknowl- edgment to all those who contributed to it. The writer wishes to express his apjn-eciation of the courtesies that were extended to him by many i)crsons connected with the ceramic industry of California. Their cooperation in making this bulletin possible is especially note- worthy in view of the fact that, on the whole, the ceramic industry today remains as one of the few mineral industries that extensively uses secret processes and secret formulae. Prof. He\\'itt Wilson of the University of Washington rendered invaluable assistance in outlining the methods of clay testing aiul in making many valuable suggestions and criticisms. Mr. John T. Roberts, president of the Stockton Fire Brick Company, generously contributed equipment and refractories to the ceramic laboratory in which the test work was done, and was ever ready to give valuable advice and infoi-mation during the progress of the work. ^Ir. L. M. Richard, consvilting economic geologist for Gladding, McBean and Company, was especially heli)ful in the field in the Alberhill-Corona district, and contributed many ideas concerning the organization of the report. Several graduate students in metallurgy or ceramics at Stanford University contributed to various phases of the investigation, especially in the laboratory. Among these should be mentioned V. J. ^linner, C. W. Brigg.s, H. J. 'Carroll, D. R. Irving and R. E. Paine. Acknowledgment is also due to Messrs. Walter W. Bradley, W. Bur- ling Tucker and C. A. Logan of the Division of ]\Iines and Mining for assistance in compiling data, and for many helpful suggestions regard- ing the conduct of the work. In addition, Messrs. Tucker, Logan, and C. ]\IcK. Laizure supplied a number of descriptions of deposits or plants not visited by the author, acknowledgments of which are made in the text. GENERAL REFERENCES. Little space has been devoted in this report to the origin of clay, its chemical and physical properties, or to clay-working processes in gen- eral. Such information has usually been included in clay reports from other states, but there seems little justification for its inclusion here, in view of the fact that there are now a number of excellent texts for those who desire such information. A few of the more important works are listed below : • Burchfiel, B. M.. Refractory clavs of the Alberhill, California, deposits: Jour. Amer. Cer. Soc, Vol. 6. pp. 1167-1175, 1923. = Schuette, C. N., Engineering principles applied to the exploitation of a clay deposit: Eng. & Min. Jour.-Press, Vol. 121, p. 964, June 12, 1926. 14 DIVISION OP MINES AND MINING Wilson, Hewitt, "Ceramics." McGraw-Hill Book Co., New York, 1927. An excellent text on clay technology, coA^ering the chemical and physical properties of clays. Not suitable for readers who have no knowledge of chemistry or physics. Andrews, A. I., "Ceramic Tests and Calculations." John Wiley and Sons, 1928. An elementary text on the methods of clay testing, and on the calculations relative to glazes, bodies, enamels and glasses. xSearle, A. B., "The Chemistry and Physics of Clays and Other Ceramic Materials." Ernest Benn, Ltd., London, 1924. A valuable reference work of scientific conceptions and data on clays. Particularly useful to research workers. Ries, Ileinrich. "Clays, Their Occurrence, Properties and Uses," 3d Edition. John Wiley and Sons, 1927. The standard work on the geology and origin of clays, with sufficient information on properties and uses to serve as an elementary text. Perhaps the best general work for tlie layman. "Clay Products Cyclopedia and Equipment Catalog." Issued annu- ally by Industrial Publications, Inc., Chicago, Illinois. A useful reference, of particular value as a dictionary of ceramic nomenclature and for the descriptions and illustrations of ceramic equipment. to CLAY KESOUUeES AXD fEKA.M U' IXDUSTUV 15 Chapter IT. SUMMARY OF THE CERAMIC INDUSTRY OF CALIFORNIA. INTRODUCTION. For the benefit of those who may be unianiiliar witli ehiy-working processes, a brief summary of clay technology is given. Definiticyn of clay: "Clays are the weathered products of tiic silicate rocks, containing sufficient hydi-ous silicate of alumina in the softened condition to ])roduce a ])]astic or semiplastic nuiss when tempered Avith water. "^ Clays may be classified into many types. In this report a classification is used that is based upon physical properties and uses. The details of this classification are given in Chapter IV. Definitions of a few of the more general terms used in clay momencla- ture are given below :- Kaolin is amorphous hydrated aluminum silicate, corresponding to the formula of Al20..5.2Si6^.2HoO and is the most important constituent of china clay. The term is \ndely used in commercial practice to include china clay and rock higli in china clay. China clay is the commercial variety of kaolin. It may occur naturally in deposits of sufficient purity, but is more often prepared by the purification of natural deposits. It burns white, and has high refractoriness, but the plasticity is generally poor. Ball clays are white or light-cream-burning clays of high plasticity and bonding power that vitrify to dense impervious bodies at compara- tively low temperatures. Fireclays are those clays that withstand high temperatures, par- ticularly those that do not fuse at temperatures below 1605° C. (2921° F., cone 27). They are used in the manufacture of fire brick or other refractories and are often used for architectural terra cotta, wall tile, etc. Face brick clays maj- be divided into one of three groups. (1) Red-burning clay; (2) white-burning clay; (3) buff -burning clay. The color, ])lasticity, shrinkage, and vitrification must fall within cer- tain general limits, dependent upon the type of brick to be manufac- tured. Common brick clays vary widely in their composition and proji- erties. TJiey are usually high in fiuxes and in most cases are I'ed-burn- ing. They should mold easily and develop hardness and strength at as low a firing temperature as possible without seriously warping or cracking. Slip clays are fine grained, and contain a high proportion of fluxes. They should melt at a low temperature (preferablj^ below 1200° C, cone 5) to a greenish or brown glass to form a natural glaze. CJaij preparation: With the exception of some of the lieavj^ struc- tural products, it is seldom possible to find a single raw material that • Wilson. Hewitt, Ceramics. ]). 7. = See Wilson, op. cit.. pp. 28-39, and Clay Products Cyclopedia, 1926, pp. 94-96, for further details. " ' 16 DIVISION OF MINES AND MINING possesses the desired plastic, tli yi(i' cliaractcri.stics tor mak- ing a given ceramic product. It is usually necessary, therefore, to blend several clays and nonplastics in order to control the properties of the finished ])roduct. For example, clays having different per- centages of iron may be blended to secure the desired color ; highly ]dastic clays may be blended with those having poor plasticity in order to control shrinkage and porosity ; feldspar may be added as a flux to lower the temperature of vitrification; crushed qiuirtz or crushed cal- cined clay may be used as a "grog" to produce a skeleton structure that is bonded by the clay, giving greater strength and less tendency to warp than if clay alone were used. After deciding upon the proportions of the various raw materials, some of them are ground separately and others are ground after mixing, either by dry or wet methods. Ball mills and grinding pans are the principal types of machinery used for fine grinding. At some point in the process, all the materials are mixed together, the proper amount of water is added, and the mass is subjected to a thorough mixing, with or without additional grinding. For the manufacture of many types of ware, the plastic mass is allowed to age in humidified rooms or under wet sacking for a period of 24 hours to one month, in order to secure uniform distribution of the water and to develop maximum plasticity. Manufacturing processes: After the clay is properly prepared, the three essential steps in the manufacture of a ceramic product of the type under consideration are shaping, drying and firing. A fourth l)rocess that is applied to certain types of ware is glazing. Shaping": The shaping of clay wares may be done while the clay is in one of the four different degrees of plasticity: (1) Drj^ pressing of pulverized mixtures to which has been added just enough water to bind the mass together when subjected to pressure in hydraulic, cam. or screw presses. This process is principally used for shaping floor and wall tile, especially the hard vitrified tile used in bath-room floors, and to some extent it is used in common brick and face brick manufacture. (2) Stiflf-mud shaping, in which si\fBcient water is added to tlie clay to permit the mass to floAv through a die without rupture. A column of clay is pushed through a hollow die by a plunger or screw or the clay may be jiressed into a steel mold by a plunger. This is the usual process for making common brick, face brick, fire brick, and roofing tile, and is the only method in use for shaping hollow tile, sewer pipe, drain tile, and electrical conduit. (3) Soft-mud shaping, in which almost enough water is added to cause stickiness. This consistency is used for the hand pressing of terra cotta and tile in plaster molds, for the shaping of pottery and stoneware on pottery wheels or in molds, for the hand molding of roofing tile over paper covered wooden molds, or for the hand or mechanical pressing of common brick or face brick. (4) Casting, in which the finely-ground mixture is suspended in water so that the resultant "slip" may be poured into plaster molds. The plaster absorbs water from the slip, gradually precipitating the solids asainst the inner walls of the mold. When the Avails are thick enough, the surplus slip is poured from the mold, the object is left in the mold until stiff enough to stand its own weight, then the mold is stripped off and the shape allowed to dry. Casting is the cheapest method of (LAV KES0UKCE8 AND C'EKA.MU INDL'STKV 17 producing pottery on a large scale, and is the principal method in use for shaping sanitary porcelain. Drying: The drying of clay wares may be done under sheds in the open, in specially heated rooms, or in specially designed humidity dryers in which the three factors of time, temperature and humidity are under close control. The type of drying will depend upon the charac- teristics of the clay used and u])on the sliape and size of tlie ware to be dried. As clay shrinks dvirinu drying, it is important that the drying be controlled in such a way as to avoid undue strains which might cause cracks in the dried ware, or lines of weakness which would i-esult in cracks during the subsequent firing operation. Firing: The i)roper firing of ceramic ware is perhaps the most important part of the process, and many tyi)es of kilns are available for the purpose. The essential conditions to be met by a ceramic kiln are control of the time-temperature cj^cle and unifoi-mity of heat dis- tribution. In some cases, kiln gases can not be allowed to come in contact with the ware, so that mufiie kilns are necessary, or else the ware is enclosed in fireclay receptacles known as "saggers." Most kilns now in use are of the periodic type, but there is a growing tendency to use continuous kilns in which the ware is set on trucks which move through a tunnel that is fired near its mid-point. Firing temperatures range from 895° C. (1643° P.) for soft-burned common brick to 1350° C. (2462° F.) for hard porcelain and fire brick. A few special products are fired as high as 1640° C. (2984° F.).^ Glazing: Glazing may be done by dipping, spraying, or painting a water suspension of the glaze ingredients on the ware either before firing, or after a preliminary (biscuit) firing. In some cases where complicated polychrome decorations are used, several firings are necessary before the piece is finished. Salt glazing is another method, wherein common salt is vaporized in the kiln during firing, the sodium of the salt reacting with the clay body to form a fusible com- pound. CLAY DEPOSITS OF CALIFORNIA. hi practically all of the low altitude areas of California there is an abundance of common clay and shale suitable for the manufacture of common brick and hollow building tile. By reason of the low unit value of these ])roduets, the raw material must be chea]")ly mined, and will not stand transportation charges from points very distant from the brick yards, which are situated near the centers of consumption. In the San eloaquin and Sacramento valleys, it has been difficult to find good bodies of clay with sufficient plasticity for the manufacture of the best quality of building brick, and some of the plants in this area have been forced to ship plastic clay from dift'erent points to mix with the local materials. In the San Francisco Bay district and in Los Angeles County, the two important centers of consumption, there are ample common clay resources. The same is true of the smaller valleys in the Coast Range and in the foothills of the Sierra Nevada. In the mountainous portions of the state, in the desert regions, and in the volcanic area of the northeastern counties, it is difficult to find 1 Pyrometric cones are extensively used in the ceramic industry as temperature indicators. See table No. 9 in Chapter IV. 2 — 54979 18 DIVISION OF MINES AND MINING suitable coinniou brick clays, but as these areas will probably never be thickly populated, such brick as are needed can be shipped in from more distant points. Tlie demand for paving brick lias never been great enough to k'ad to an intensive search for red-burning shales of the type used elsewhere in the United States for paving brick manufacture. A few such shales are known, and one or two deposits are being worked, but, for the most part, the demand for paving brick, sewer pipe, conduit pipe, and other red-burned vitrified products has been met by a blending of various clays, with or without grog. Three deposits are of special interest in this connection: the Natoma da}' (see samples No. 210 and 212), which consists of fine gold-dredge tailings deposited in settling basins ; the Goat Ranch shale (see sample No. 282), an Upper Cretaceous shale in Santa Ana Canyon; and the Santa ]\Iargarita shale (see samples No. 216 and 217), from an undeveloped deposit along the Southern Pacific Railroad near Santa IMargarita. The general distribution of the high-grade clays of California is shoAvn on Plate I. The high-grade clays of the state are found mainly in deposits of Eocene age, although there is one important area of Pleistocene clay, and the importance of certain beds in the Upper Chico (Cretaceous) is just receiving recognition. Approximately 90 i)er cent of the high- grade clays of the state are now being mined from one of three areas: the Alberhill-Corona district in Riverside County ; the lone district in Amador County ; and the Lincoln district in Placer County. The age of the clays in all three districts is Eocene, and the dei>osits were formed by sedimentation in inland seas, with or Avithout subsecpient alteration. The Alberhill-Corona clays occur in an area in the Temescal Valle}' some twelve miles long and two miles wide. In many places the clay beds are three to four hundred feet thick. The clays were laid down in Eocene time in an arm of the sea. The region is characterized by a discontinuity of structure that arose from folding, faulting, and erosion subsequent to clay deposition, and by extreme local variations in the individual clay beds caused by variations in the conditions of sedi- mentation. A wide variety of red, pink, and buff-burning i)lastic clays and a good range of plastic and semi-plastic fireclays are produced in the district. The colored clays are used for face brick, roofiug tile and red earthenware, and as an ingredient of sewer pipe, electrical conduit and other mixes. The buff-burning clays, generally refractory, are used for architectural terra cotta, stoneware, decorative tile, pottery, etc. The refractory clays are used for fire brick and other refractory shapes. A few selected varieties are sufficiently free from coloring compounds to ])ermit their restricted use in white-burned products. The typical clays are chai-acterized by excellent plasticity, low or medium dry strength, low or medium drying and firing slirinkage, and open fired texture. A few varieties are found that possess high dry strength and high shrinkage, and that vitrify completely within com- mercial firing ranges, but these are the exception rather than the rule. The proportion of sand in the clays varies widely from almost pure sand to pure clay, resulting in a wide range of commercial varieties. The lone clays and sands occur in a belt about twelve miles long and one-half to one mile wide. The total thickness of clay is not knoA\Ti, PLATE I SISKIYOU ^^ ■^-:-TC:.T I M D 8 C I ■CALIFORNIA STATE MINING BUREAU- Llovd L. Root iTATE MINERALOGIST OUTLINE MAP • Of CAUIORNIA SCAIX alturas izi ' ) i'l A...S. \ -"•■•-'' SHASTA, . « 'iRINI-n' L A S 5 E M ^■■■| T E H A M A(^ PLUMAS I < ,.., ^ ^^ . -eLEHN/BUJlE^.^S, ERRA 1 -..?-s-,„„>„ .- >"->.l_| [MiKDOCINO .! Z"^"-ij°'°""-' I SHOWING LOCATIONS OF HIGH-GRADE CLAY DEPOSITS FROM WHICH SAMPLES WERE TAKEN. JANUARY. 1928. ACCOMPANYING BULLETIN No. 99. SAN FRANCISCO^ V'O.'rTB • ^■^' '^ '"" N \ 5kHT» C«Ui y' -J /. »A «*r(^ / ^ IMD(Pft»01HC[ X ^ J e^, 5»N ^»,.,..o_r- -■ 1 N Y 0\ <5 C"""'^ \aCNlTO • * '< p«.«... N, UnteSCV^--^ ,„. ... /•"•?"(' •t U L A R E \ ^ \ ^^:^ _ '^z , "--\ f , o, K 'E P N I • >. / ° "=." I S A N . B E R N A R D 1 N < ; . _l "-."i •'-"" .,.„„ _ \S»HTA BARBARA , \ ! ^ J I \ I ^ ^..ui.o.o VENTURA* -.,_ ^^VtnTUWA ^ 5»NBEIINAR0lt1O .. " <^ V. l05«~6tUS ® ^- ■='<^^;>' \ * _ /' ' ^ CX. »^V "'45*^'" R 1 ^ > " ^ '*' 5.rA. •"« ^f •nil.. \ *... ^.-^^ • '^^ PERIAL \«SAN DI EGO . MEXICO "*"' 54979 — facing pasre 18 CLAY RESOURf'ES AXD fERA:Mrr INDUSTRY 19 but in a nuinber of places a tliiekness of over 100 feet lias been demon- strated. The beds are more continuous, and have less local variations in the character of the material, tlum is the case at Alberhill. The area is important for its liiyh-yrade (iiechiy and tire-saiui. Some plastic pink- and buft'-burnin<>: clays are also produced for use in terra cotta, stoneware and pottery manufacture. The fireclays are the most refractory that have thus far been found in the state, but are charac- terized by low dry strengtii and high firing shrinkage, with a strong tendency to crack when fired. The fire-sands are composed of quartz- mica saiul with from 10 to 25 ])er cent of clay, and are im])ortant as a nonplastic ingredient of fire brick mixtures, to diminish the shrinkage and the tendency to crack. Future develoi)ments in tliis area are expected to greatl.y extend the known dimensions of the clay beds, and to disclose other varieties of clay not now accessible. The Lincoln clays lie in an isolated remnant of the lone formation (Eocene), protected by a lava capping. The beds underlie a low hill adjoining the toAvn of Lincoln. The claj^ is continuous over an area of about four square miles, to a depth of ap])roximately 100 feet below the lava capping. The Lincoln clay is an excellent butf-burning plastic fireclay that is especially valuable in the manufacture of architectural terra cotta, faience tile, fire brick, and other products. There are also beds of pink-burning clays that are used in seAver pipe, roofing tile and face brick mixtures. The Lincoln clays have excellent plasticity, medium dr}- and fired strength, a long vitrification range, and, although the shrinkage is high, the clay can stand rapid firing without cracking. Some other clay producing areas of lesser importance are: (1) The Cardiff-Carlsbad area in San Diego County, containing excellent fireclays, some of whicli are closely similar to the famous (Iros-Almerode fireclays of Germany; (2) The Santa Margarita Rancho deposit, near San Juan Capistrano, San Diego County, containing important deposits of higldy aluminous fireclay; (8) The Hunter Ranch deposit, near El Toro, Orange County, where there is an excellent firecla.y, associated with a bed of kaolin and sand from which a high-grade kaolin can be recovered; (4) The Goat Rancli deposit, in Santa Ana Canyon, Orange County, an TTpper Chico (Cretaceous) deposit of flint fireclay. California is especially favored with resources of noni)lastic ceramic materials. At Campo, San Diego County, is a large de])osit of excel- lent felds]iar. and many other feldspar deposits are known in southern California. Silica is available in many forms in California and near the border in Nevada. A large deposit of quartzite has been found in the desert south of Barstow, from which silica brick is being made. Talc, used in some floor-tile bodies, is available from a number of sources. The most extensive deposits of andalusite and cyanite in the United States occur in California. These minerals are of increasing importance in the manufacture of high-grade refractories. The most im])ortant ceramic materials that are thus far lacking in California are ball and chitia clays equal in purity and iniiformity to those from the deposits of England or from the eastern T'^'nited States. A clay possessing the projierties of a mixture of the two varieties has been found in San Bei-nai-dino County, and a good china clay has been found in Nevada, but thus far ])roduction has been small, and most of the ball and china clay requirements of the California industry are met by importation from the eastern states or from England. One of 20 DIVIRIOX OF MIXES AND MINING the factors that lias liindered the establishment of a local clay Avash- ing industry to produce china clay is the low price of Beljiian "lass sand at Pacific coast ports, making: it unprofitabh^ to market tlie (piartz sand which would be a by-product of kaolin waslnng-. Since the yield of kaolin would be but 20 to 30 pec cent from the known deposits in California, the importance of a satisfactory market for the sand is apparent. Wliile a few small deposits of bone clay have been found in southern California, highly aluminous clay is relatively scarce, and no commer- cial deposits of diaspore, bauxite or gibbsite^ have been discovered in California. MINING METHODS. Most of the clay deposits of California are mined by open pit methods, and with the exception of most of the common clay deposits, hand methods predominate. Where a production of the order of one car (50 tons) per day or more is needed mechanical methods are in general use, if topographic features are favorable, and if no hand sort- ing of the clay is necessary. Drilling and blasting are necessary at many of the deposits. The holes are usually drilled with hand augers, and blasted with light charges of low-power explosives. As a rule 3 nearly vertical bank is carried, and the height of the bank corresponds to the thickness of the bed being mined. Stripping of overburden, if any, is carried out in advance of mining, on a separate bench. The hand methods in use involve pick and shovel loading into auto trucks, wagons, mine cars, wheelbarroAvs, or loading chutes, depending on local conditions. The mechanical methods include horse-drawn scrapers. ]iower-driven drag scrapers, and power shovels of various types actuated by gasoline or electricity. The scrapers usually load directly into hoppers, from Avhich the clay is drawn oif into auto trucks, industrial railway cars, or onto belt or bucket conveyors. The shovels load into auto trucks, or into industrial or standard railway cars. Most of the underground mining is done by the room aiul pillar method, from a tunnel entry, with only such auxiliary timber support as is necessary to support localized blocks of loose ground. While pillars are robbed as much as is practicable, from 20 to 35 i)er cent of the clay must be left in the pillars to support the workings. Transportation from the pit to the plant or railroad siding is done at many properties in the original vehicle in which the clay is loaded. At other properties a loading platform or chute is placed as near the pit as possible, and the clay is transferred to cars on an industrial railroad or into auto trucks. Most of the clay mining in the state is done on contract, especially at smaller properties. To one familiar Mith metal mining, the methods in use at many of the properties seem needlessly crude and wasteful of human energy, but the short working season, seldom longer than from 1 These three minerals are t\'pes of aluminum hydi -)xide. Diaspore contains 12-14 per cent of water and has a formula approximating to AloO^i.HoO. Bauxite contams 20-24 per cent of water and corresponds to AI0O3.2H.O. Gibbsite contams 27-3o per cent of water and corresponds to AloO.-..3HoO. See Searle "The Chemistry and Phvsics of Clavs," p. 3.39. The bauxites are used in the manufacture of metallic aluminum, and' are valuable for the manufacture of a .superior type of fire brick (diaspore brick) that is more refractory than ordinary fireclay brick. These brick are used, among other purposes, for lining the clinkpring zone of cement kilns. CLAY RESOURCES AND CERAMIC INDUSTRY 21 'Siny to October, the eoinparatively small seale of operation, the fluctua- tion of demand, the irre«iularity and small size of some of the deposits, the necessity of hand sortin.n' in a number of cases, and the fact that many of the deposits are mined uiuler a royalty lease, all must be it work range from 10^ to 25^' })er ton for scraper or shovel loading, to 2()(^ to aO^ ])er ton for hand loading. Hand sorting nuiy double the cost of liaiul loading. Transportation to the pit mouth, or to a bin within a few hundi'ed yards of the pit, may add fi-om o^ to 2o^'- ])er ton. liieidentals may total from 'h- to 25^, making the total direct cost vary between the approximate limits of 20^ and $1.50 per ton. In addition, many of the properties are several miles from a railroad or plant and must stand a transjiortation cost that may be in excess of $1 per ton. The longest auto truck haul noted was 15 miles, aiul there are a number of deposits where the haul is from thi-ee to eight miles from the pit to a railroad or plant. Where a royalty is paid, the charge is usually from lO^'- to 25^ per ton. rnderground mining- costs are naturally higher than open pit costs, but the direct cost of mining and loading, including hand sorting, is seldom in excess of .$1 per ton. Haulage and t ranspoi'tation costs must be added. As an indirect indication of costs, the selling prices of a number of clays may be cited : The price of Alberhill clay f.o.b. gondola cars at Alberhill ranges from $1 per ton for the cheaper grades that occur in large deposits and that are chea))ly mined by mechanical methods, to $5.50 per ton for the rarer varieties that are hand sorted and may be mined by uiulerground methods. The price of Lincoln clay, mined by a ])ower shovel from a large ])it. is nominally $1.75 ]ier ton, f.o.b. Liiu;oln. CERAMIC PLANTS. A check list of tiie clay-working jilants of (•alifornia, with the products made in each, is given in Table 1. It will be noted that the majority of the plants in the state are in or near the two major centers of po])ulation and industry, the Los Angeles area, and the San Fran- cisco Bay district. However, common brick and hollow-tile plants are well distributed among the lesser centers of population, and there are a number of important manufacturers of high-grade ceramic products whose ]>lants are at some distance from the larger centers. Some of the plants in the latter group have been built adjacent to clay pits in order to secure close coordination between the clay quarrying and the manu- facturing plant. Since freight rates on finished products are higher than on raw materials, it is advantageous to locate the i)lant near the geogra])hical center of consumption of finished Avare. The check list also reveals the wdde diversity of the California industry and sliows that nearly all of the ceramic products now in use are manufactured wi one or more California plants. The important excei^tions are magnesia brick, chrome brick and chemical porcelain and stoneware. Magnesia brick were made for a short time during the World War. Avhen foreign supplies were unavailable, and earlier attempts were made by various companies, but the business is uneconomic under normal conditions. 22 DIVISION OF MINES AND MINING o Cast iron enameling. Porcel in specialties. Electrical insuhtors- Flower pots, olla9, etc... Stoneware. Sanitary ware. cc O < u 3 Q O oc Q. < CC o o < cc UJ u Ik o I- X o z UJ Art or garden pottery Kitchenware. Tableware. o o Special refractories - Silica brick. Fire clay brick... Wall and fire place tile.. Floor and terrace tile. Flue lining and chimney pipe. Roofing tile. Conduits. Terra cotta. Hollow block. Drain tile. Sewer pipe. Face brick - Paving brick. Common brick. no •r* OS C I o cSoo c: ci.5 rt c3 rt o C3 ra C3 .^ • 1.-,^ y^^ _^ '-^ , dl^ o O go-" .S-- 3 CD o a; 3 o bo Ci pa J « O O c«0(aS -*- L^ 'C 0.1^ .— t- ty- £- -rr £ ",= = 5 ,0 OH g o E a 5 s o o CLAY RESOURCES AND CERAMIC INDUSTRY 23 X X X X X X K X X X X X X X X X X X X M X X XX X XX X XX X XX XX XXX X X X X X X X X XX X X X X X X X X X X X X X XX X X X X X XX XX X XX X X X X X X X o n o C s o O ^ o SO §^ CO >> 25 X O o :o ;:=o a 3 , , ', 6 6 ; dO O 'O m o d QJ « u so— = ■« c H>>^-g d^^ c 2 S 2 rs 0:^-5 2^ '^ £ 5 a = cj *- 'tZ "tir 'c C C3 1; o cj S£ £ G S O ^ c d 9 l-iixioc SS ^_, ^'^ X"^ -y. ;-n . ^ u *^ ^^£■5 5oo :33a •1^ o "^ ' OS c c j^ J ^ aj3 « c =: a k fe03 = ■£:■:=.= Hr« •i -r; • >^ '^ C'C Cj ^ ^ ?- — ^ ^ .z: ^ 2 3j -. .mm :J3 • cs = H-S-i 'm-^'cCwwSCswccs— u:^-:!^ c^m j n — (Cm : ^ at - :m = = 5 i- ■— o ... - S o o »; ca odd .COO jSm^ m-a o o -^, =-n " o £m; ^ •- r" -t:; *- <" «^ • E £ c 3 .r .2 -"^ - K cc H H > >: :S : -a _• "o 2 24 DIVISION OF MIXES AND MINING u I a UJ oc 3 I- U < < CO f- o 3 Q O OC o. cc o < CO I- < oc llJ u ll. o H o X u CO < -a S o Cast iron enampling. Porcelain gpcci-iltips^ Electrical insuhtors. Flower pots, ollas, etc- Stoneware. Sanitary ware. Art or garden pottery Kitchcnware. Tableware. Special refractories. Silica brick. Fire clay brick. Wall and fire plice tile.- Floor and terrace tile. Flue lining and chimney pipe. Roofing tile. Conduits. Terra cotta. Hollow block. Drain tile- Sewer pipe. Face brick. Paving brick. Common brick. Q ° E a o X X M X X X X X XX I Tj» CO o— o «-H (M -^ 1-1 ,— I -^ ^- — . re tc r- 00 c^ re ro ro -^ ic r>- 1— c^ (M ccco -^— Tj"'-j« ic t^r^oooo oeoooooooo OOO'-f- <^^ o 33 L- a o "S'- !: J . ° ?r ^ C '- o -^S KC-So c c^=:i iis£^> , • t . . o >> . . u c _; £ " ■ -a g S " M t-' '£ § dO=8 ■Sh-c: — ."x txi:; d =o - CC - ■ h ;s I h. . o = •2 ■s o = 3 — -S M — *" :s s c CLAY RESOrUCES AM) ( EKA.MU IXUUSTKY ZO — — X >: X M X V. X X X X X X ^ . y X X X X y X X X X X X X X X X X X X X X X X X ooooo cc •o oooo CI ■^ ■* CC — (M C'l CI C*l CI CO CO cc cccc cc C'llMO cs (N (NC^ CI CI CI d CI CI CI CJ M CI CI CI E j 3 V 3 c ■ . I 1 I 3 • ' ■us ; : ; ; 1 o m b« - ■" - o (33 •>> 1 c X :s £i5 c5J-5 'y 5 >a:":;«8 d ■ d 5| .2 S -c o = 9 d ^-j; •" ,^ fe £^^-€^a o w H u cs ■r. as >- = -■- C c t. H 5 P3 5 c c ^ 3 s ^ j ^ ^ 4 — ^' n sS s « M zi £ i: - = = ==« Ci e. ~ o" j/ia: v: 'X. ■s <2 CU:S;^cg-^M o vi ■ 1-s ■i ^% s >;^ c = O " 3 •a o o X = ^ — jipa S3 rt t- 3 I-. c o^ g ^ O CJ C 26 DIVISION OF MINES AND MINING MANUFACTURING METHODS IN CALIFORNIA PLANTS. Common brick: In California, one common brick plant uses the dry-press process, and the other plants are nearly equally divided bet-u'een the soft-mnd and the stiff-mud process. Nearly all of the plants use drying sheds in tlie oi)en, but some use drying racks in an enclosed and heated building, and a few use waste-heat or separately- fired tunnel driers. Field kilns are preferred in southern California, where there is little rainfall thi-oughout the year, and continuous kilns of the Hoffman type are preferred in northern California. Oil is the usual fuel for the field kilns, although natural gas is used at some plants which are located near the oil fields. At some plants, gas is used during the water-smoking period and oil for the balance of the firing cycle. The continuous kilns are fired with coal. Firing tempera- tures range from cone 08 to cone 1 (950° to 1160° C). No mechanical hacking, setting or loading machines are in use in California. So far as could be ascertained, none of these devices have been given a trial in the state. It would seem that even though such machines in their present form may not be entirely satisfactory, the hope of saving from 25 to 40 man-shifts per 100,000 brick would be a sufficient inducement to encourage the development of automatic brick- handling machines, especially in the larger plants. Hollow Mock: All hollow block are shaped in auger machines. Some of the plants making hollow block are also making common brick and both products are subjected to the same drying and firing treatment. Waste-heat or separately-fired tunnel driers are in use at a number of l^lants. Field kilns are widely used, but several plants use Hoffman kilns, one uses a Haigh kiln, and a few use use round do-^-n-draft kilns. Firing temperatures are usually between cone 04 and cone 3 (1060° to 1170° C). Face hrick: Most of the face brick of California is shaped by the stiff-mud process. Much of it is repressed. The dry-press method is used at a few important plants. Drying is usually done in waste-heat tunnel driers, and round down-draft kilns are used at all plants for firing.^ The firing temperatures usually approximate cone 02 to cone 5 (1125° to 1205° C). Sewer pipe: All sewer pipe is made in presses which are usually operated by electric power. Drying is done on drier floors which are usually heated by steam or waste heat from the kilns. Round down- draft kilns are used for firing and the firing temperatures range from cone 02 to cone 5 (1125° to 1205° C). The dry strength of some of the sewer pipe mixes in use in California is too low^ to permit setting to the full height of the kilns, so that the capacity per kiln is not so great as at most of the eastern plants where stronger clays are available. Drain file: There is little demand for drain tile in California and it is only made in a few plants, where it is sha]ied by auger machines, di-ied on heated drying floors and fired in round down-draft kilns. Terra cotta: Architectural terra cotta is an important product in California. A particularly fine example of its use is shown on the 1 The wide range of colors demanded by modern architectural design is secured by varying the body mixture and by the normal differences of temperature at different liarts of tlie kilns. CLAY RESOURCES AND CERAMIC INDUSTRY 27 frontispiece, Plioto No. 1, which is a view of the Kuss Building, in San Francisco. The typical body in use in California consists of a siliceous plastic fii-eclay mixed with an equal weight of nonplastics, such as quartz sand and grog made by regrinding rejected terra cotta from the i)lant. This produces a body liaving an absorption of about 15 per cent, when fired to cone 4 to 6 (1190° to 1230° C). The mixing, pugging and aging of tlie body mix is highly important, and due precautions are taken at all ])lants 1o ensure uniformity of the plastic mix that is sent to the pressers. All shapes are made by hand pressing in plaster molds. After drying to leather liardness, the molds are stri])ped and the ])ieces are finished by hand, after which they are dried and s])rayed with glaze. A few Carrier humidity driers are used in California in place of the usual method of drying on heated floors. In California, the ware is fired to cones 4 to 6 (1190° to 1230° C.) in round down-draft kilns. A considerable quantity of garden pottery is made in California, either as an auxiliary product in the terra cotta plants or in smaller plants making a specialty of this class of ware. The body mix and manufacturing methods are similar to those used for making terra cotta. Conduits: Electrical conduits are shaped by auger machines, using a mix similar to that used for sewer pipe. ]n California, they are usually dried in waste-heat tunnel driers. Round down-draft kilns are used at all plants. Roofing tile: Roofing tile is popular- in California on account of the l)revalence of KSpanish architecture. Hand-made or hand-finished machine tile is in considerable demand for the better class of homes, and machine-made tile is widely used on homes, apartment houses, hotels, schools and even on office and public buildings. Most of the hand-made roofing tile plants are small and have little equipment. Drying is done under sheds or in a barn, and firing is done in simple rectangular or vertical kilns, most of which are up-draft. There are a number of large plants making machine-made tile with an auger machine. Many of these use waste-heat tunnel driers. Beehive kilns are in general use at these plants, but one plant uses a tunnel kiln. Firing temperatures approximate cones 06 to 02 (1015° to 1125° C). Several plants pro- duce a hand-finished machine tile and finish the upper surface by hand before drying is complete. Such tile has nearly the same appearance as hand-made tile when laid on the roof, but is considerably cheaper. Present-day architectural design calls for a wide range of colors in roofing tile, as in face brick. With machine tile, the color range is secured by varying the proportions of buff- and ])ink-burning clays that are used with the red-burning clay body, and by sorting the diff'erent colors produced in different parts of the kiln. In the manufacture of hand-made tile, the mix is seldom varied in a given plant, but the color variations are obtained by normal variations in firing temi)erature in dift'erent i)art,s of the kiln. In fact, the kilns are so small and so simple in design that it would not be possible to secure a uniform burn of the entire kiln. Individual tile usually show a considerable color differ- ence between opposite sides or ends of the tile. This feature, together with the irregularity of outline, largely accounts for the artistic value of hand-made tile when applied to moderately small roofs. It should be noted, however, that hand-made tile can not be relied upon to make 28 DIVISION OF MINES AND MINING a water-proof roof, on account of high porosity and cracks in many of the tile. They are often laid over machine tile. Fhie lining: ]\Iany of the fire brick and architectural terra cotta phmts in California and some of the sewer pipe and roofing tile plants make flue lining to supply the trade within their marketing territory. A siliceous refractory mix is used, similar to that used in architectural terra cotta or in low or mediunl-duty fire brick. Eound shapes are made in a sewer pipe press, and square shapes are made in an auger machine or by liand pressing. Waste-lieat tunnel driers or hiunidity driers are sometimes used, but a connuon method of drying is on floors in heated rooms. Floor tile: There are a number of important plants in California that make vitrified floor tile by the dry-press process. Englisli or Florida kaolin and English, Kentucky, or Tennessee ball clay are usually used in wliite tile, together witli California or Arizona feldspar and California or Nevada silica, although Illinois silica or Belgian sand is used at times in place of California silica. Some plants have intro- duced California talc into white vitrified tile bodies witli considerable success. Colored tile are made bj' substituting colored clays or by adding coloring compounds in the proper proportions. Power-driven presses are gaining in favor at the larger plants for the shapes and sizes most commonly used, but hand-presses are preferred at the smaller ])lants, and are used at all plants for special, or infrequently used, shapes. Specially designed tunnel kilns are in successful operation at one or two plants. There has been a good market in California for rough-textured colored floor tile, and a number of small plants have been built to satisfy the demand. Most of these use a red-burning clay, or a mixture of bulf- and red-burning clays, with grog or siliceous sand. Hand molding in plaster molds is extensively practiced, but competition has led to the use of tile augers in many plants. If desired, an undu- lating surface can be imparted to machine-made tile by hand treatment before drying. Oil stains are frequently applied after firing to modify the surface color or lustre of the tile. The active demand for this class of ware in recent years has stimulated artistic development, and the product from nearly every plant possesses an individuality of design, texture, and color. In a few plants, however, slavish copying of successful designs from other plants was noted. Wall and fireplace tile: The artistic development of California decorative tile is an outstanding contribution to ceramic art in the United States. There is perhaps no other region in the world today that produces such a wide diversity of wall and fireplace tile, or that is so well prepared to create new designs for private homes, hotels, stores and office buildinus. Several factors have contributed to this condition, among which are the following: (1) An abundance of suit- able clays, cheap fuel and power, and low-unit labor costs which make it possiijle to produce certain types of tile so cheaply that they not only find an important local market, but can also be shipped to eastern ])oints on a competitive basis. (2) An active state-wide building pro- gram that is based upon the necessity of providing for many new industries each vear and for new homes for the thousands of people CLAY RESOURCES AND CERAMIC INDUSTRY 29 who annually enter the state from the east and middle west to become pennaiieiit residents of California. {'■]) The jirevailiii^- pi'osperity and resultant liijih standards of livinji' whieh are more apj)art'nt on the J*aeific Coast than in any other section of the United States. (4) The diversity of architectural design arising in part from the foregoing faetoi-s. and in i)art from the luitural environment of California, where climatic conditions favor out-of-door life throughout the year, and where comparatively low land values in most residential districts make it possible for a home builder to acquire sufScient land to avoid tlie necessity for a cramped architectural style such as must be used in more congested centers of population. The dominant motive of Cali- fornia architecture is Spanish-American, the keynote of Avhich is to be found in the missions that were establislied under Spanish rule in the latter part of the eighteenth and the first part of the nineteenth centuries. Suggestetl by this beginning the Spanish-Moorish, ^lexican- Aztee, and Pueblo Indian styles have been extensively used. Those desiring a relief from these types, yet desiring to build in keeping with their local surroundings, have often chosen Italian desigiis. Still others, desiring destinctive effects, and sensing the possible over- development of Latin types in many districts, have used New England colonial, southern colonial, English, Norman, and other types, many of which are hybrids or are indistinguishable as formal styles. Refractories: The manufacture of fire brick in California has now progressed to the point where practically all of the local demand for fireclay- brick and special shai)es is met by California products. Several manufacturers are making a fireclay brick with calcined clay grog that gives as good or better service as the best grades that are produced elsewhere in the United States. The demand for medium or low-duty fire brick is usually met by a (luartz-grogged fireclay product. One manufacturer is developing a flint fireclay brick. Another manufac- turer has been marketing a silica brick for the past two or three years. ]\Iullite refractories are being manufactured at a plant in Los Angeles, using cyanite from a large deposit in the Imperial Valley desert. No commercial deposits of bauxite or diaspore have yet been discovered, so that the state is still dependent on eastern products where a diaspore brick is needed, as in linings for the hot zone of cement kilns. How- ever, sufficient ((uantities of bone clay have been found on several properties in southern California to permit its use as calcined grog and as a portion of the plastic content in the manufacture of high- alumina brick. The methods of manufacturing refractory ware in California follow the usual practices employed elsewhere. Most plants are equipped with auger machines for shaping the standard shapes. The better grades of brick are repressed. Some hand-molded standard brick are made, and are re])ressed in hand-operated presses. Special shapes are made bv hand-molding. Drving is nsuallv done in waste-heat tunnel driers, although a few humidity driers are in use, especially for the shapes that are difficult to dry. Round down-draft kilns are generally used for firing, and the firing temperature for most of the fireclay brick produced in the state is cone 11 (1325° C). One of the most notable developments is the use of a tunnel kiln by the Vitrefrax company for firing mnllite brick at cone 29 (1640° C). 30 DIVISION OF MINES AND MINING Tableware: Plain and decorated .semi-vitreous table and hotel ware is made at a number of plants in California. Thus far, these ])lants have used imported clays, in conjunction with feldspar and silica from local sources. One ])lant, the Empire China Company, expects to j>o into production in tlie spring of 1928 on vitreous ware, using a Cali- fornia feldspar and silica and a Nevada china clay, together with a certain amount of Florida clay.'^ The manufacturing methods follow Well-established practice. Kitche7i ware and sionewarc: A number of potteries in California are nuuuifacturing kitchen ware antl stoneware. In most cases, all materials used in the body mix are obtained from local sources of supply. Slip clays for glazing have thus far been imported from other states. The usual manufacturing practices are followed. Art pottery: There are a few small potteries devoted to the produc- tion of distinctive lines of art pottery. As the type of body and the plant practice is different at each of these, the reader is referred to the check list, figure 1, and to the plant descriptions in Chapter III for further details. Red earthenware: The local demand for flower pots, ollas, earthen- ware household utensils and other red earthenware products is met by a number of plants, some of which specialize in one or more of these products. Sanitarij ware: A complete line of sanitary porcelain, with the excep- tion of bath tubs, is made at three plants in California by the casting process, using imported clays, California or Illinois silica, and Cali- fornia feldspar. All three plants are e([ui]iped with tunnel kilns for both the biscuit and glost firing. Biscuit firing is usuallv at cone 11 (1325°C.), and the glost firing is at cone 6 (1230° C). 'Three metal enameling plants are devoted to the manufacture of enameled cast-iron sanitary ware. Semi-porcelain plumbing accessories are made at three smaller plants. One of these uses a body made entirely from California raw materials. Electrical insulators: The manufacture of high-tension electrical insulators probably presents one of the most difficult ceramic ]iroblems of modern industry. The industry is rppresented in California by one plant, that of the Westinghouse Electric and Manufacturing Comjiany, at Emeryville (c.v., p. 45). California feldspar is the only local material used in the body mix. Semi-])oi-celain electrical accessories are being made at three small plants in California. Thermal insulators: Although accurate statistics are unavailable for publication, the bulk of the diatomaceous earth insulating brick output of the United States, if not of the world, is produced in California. The Celite Products Company at Lompoc, and the Stockton Fire Brick Company at Stockton are the only producers at present. The produc- tion of sawn natural blocks of diatomaceous earth, at one time of importance, is now relatively small compared to the production of molded (hand or auger-machine) and fired shapes. 'Personal communication from G. Ray Boggs, December 8, 1927. CLAY RESOURCES AND CERAMIC INDUSTRY 31 STAT I ST J ('S. BRICK AND HOLLOW TILE. The briek and hollow tile statistics compiled by the State Division of Mines and Alining inelnde all classes of brick. The detailed figures of production and value for 1926, by counties and by class of ware, are given in Table 2. This is a com])anion to Table 6, referred to later under pottery clay, in which the segregated figures for other clay products are given. Table 3 gives statistics for the common brick industry of California, by y(>ars from 1896 to 1926 inclusive. The annual value of the com- mon brick production is plotted to a ratio .scale ou Tlate II. For com- parative purposes, Plate II also includes the curves for the average unit value of common brick per thousand, and the gross annual value and the average unit value per barrel for cement during the same period. The rapid growth of the cement industry relative to that of the common brick industry is of special interest, as is also the comparative trend of prices in the two industries. The trend of cement prices reflects the economies of steady technical and mechanical prog- ress in the cement industry, and the increasing size of plant units. The trend of common brick prices closely parallels the fluctuations in com- modity prices and labor wages, as modified by fluctuations in the unit cost of fuel, as a high percentage of the cost of making common brick arises from labor and fuel costs, and there have been no im])ortant technical or mechanical improvements in brick manufacture during the period under review. The influence of the San Francisco earth- quake of 1906 is strikingly shown by the decline of the common brick ])roduction and the continued rise of the cement jn-oduction after a slight recession following the financial panic of 1907. POTTERY CLAY. The term 'pottery clay' as used in State Mining Bureau reports refers to all clay other than that used in the manufacture of common brick and liollow tilc.^ The production of pottery clay in California in 1926 is given in Table 4, and the production by years, from 1887 to 1926, inclusive, is given in Table 5. The production of pottery clay products in California during 1926 is given in Table 6. 'For a further elaboration of this definition see Cal. State Min. Bur. Bulletin No. 97, p. 94, 192(i, or other annual statistical reixirts Iiy the Bureau. 82 DIVISION OF MINES AXD MIXING 2: S _l p ^ 00 < £ 2; I = fc -"^ CO ^ »c cri -J* c^i CD M ws ci'co'-f-':c'i>rr>r ^ irTco c{ CD CT 3 CO t-^ifJ'fl^COt^C'JO'— 'Ci Oi oco ^- eo •-• III 1 I I 1 CO 00 c^ J3 J ! !,-« I CD I I I I »o c^ Ss CO I ir^ 1 1 1 ■ 1 C4 CO CO ' .Tf . '^ " ■ ■ 1 ,-1 CO o' H CO ; ; t^ i 1 1 1 1 1 1 .-H . 00 , a> (M, ,,,_,, .-III,,, 1 ,0 W3 -0— - 3 00' : I 1 o" ; -*" ! I I I ! ! I CD* 1 00 ^C3 •^^ ^0 CO . , to CO m-.C ^^"5^1 "^ co_ O-C M K> «» 1 ; ; ; I I J I I ; ; i c..t:.S ©& >> a _^ (N 1 I-rt* !^ III 1 IcO 1 CO S c c Oai .t^'CO . C>2 is eot .t^-t— 00 I CO > !^' ;co"* •III I lo" ; 0" 6 : :^ 1 i I I i i" i CO t . ( r CD ■ 10 1 1 1 f 1 t (Ml 1 CO Itli^H.COl'lll 1 Ol ■ »o 0) . . . ico^ .r* 1 1 1 1 1 1 < 0^ ^ I I I 1 0* ! 00 I I I I I I »o I I •^ C3 00 00 '■<*«, CO: I t* >- I 1 i 1^ 1 III!! I I I (D «^ Im P^ -4^ • • .O't-* ■• iiOi 1 ^^ i^ .. it-,,.^ ,, lOOi ' 00 ■ . lO'O '• itMi t CO I I * 1 1^' ! C5"» • • ! I I po I ! cT ; ; 1 * , I I I '^ 1 1 (M < > CO ^ CO Cti ■ '^ 01 10 (M 10 ' ' ' r- '^HCO-rfl-OO 'OC^-^CX)00 <-H 1 1 . os 1 CO r- -- ic ■*_ en T)' crs i-^ t^ 10 II 1 *o 3 ; rt^'to'io'cOC^' 00-* CO cor- TT ' S «©t^io^t^ r- c^ C5 C5 CO c ; •-' 1— 1 i-t .-t '^p , , ^co(>) r^ ■ i . CO . C-l i~« U3 Tj- • ; ; : ; ; ;"= ; : a ; 1 1 1 1 ."^ . u 1 5 ' — ■ ' s '*^ ' '^ ■ OM • ; ; ; ; I'E IX. M . s 1 . I.H a : ; ; : ;3 is i^-g ; i i i i il if i"is i i i i i il^l i^fg III \m i i i i ii^i \m '. 1 1 1 1 t." 0" tT 1 8 2 3 ' ' § • aO a'^ =«-2r-n li-|il--3:-|355 i i i is : ^3£:«52>«c55 5-2^ ^^ ^ ^'^ f Oo"'^'tC l^'l-*" Tt^* icTo CI CO 3 CO t-^»OM'i^cot^Mc:'— "OS Oi oc2 — C^ 1' > ** CO o C4 I I !oo ! 1 1 > T-< t . 1 1 DO Ci .E "1 •3^ O ^ ■ r .O I 1 1 .0> 1 I , , ^ OO J > "2 1 Oi 1 1 ■ C^ 1 1 1 . Ci I I !<=>' I I I I c-i" OO^ <^ ^-• III 1 1 I I CO 00 ^'^ I I 1 I t/> 1° O ' . ^H 1 CO . . . 1 »0 M -2-S C o CO 1 il^ . O ' 1 1 • < ^« f^ "^ . f^ . ■ «= CO ^*^^. ■^ co_ H-* «» ! I ; ; I 1 I r I I I I c..ti.S So . > > u >>C. ^ M I !tj* 1,1 ! ! ! I Ico I CO a c C3 0>i it^'CO iir 1 lO I C3 5^ 2^ CO_ I 't^. "~^ III . .(» . CO I • I '-<" I CO * » I I I I I o I o o' s \ :^ : ; ; : : r ; CO 1 1 1 . CO " tr> 1 1 1 1 1 1 Ml 1 CO 1 . 1 .w .CO < ' t • p I O I . u:) O) ttiiCO't^ O * 1 o_ 3 I I I ! o' ! oo~ I ! J I ! I »o" I I -*" J^ 00 !^ o oo M^.CO t^ lO K* ; ; ; ;&^ ; I I I I I I I I s • 111 1 t > 1 1 1 1 1 ■ ^ hi -u II lo II^ I '< I ifD I I ,_, c ■ r . t-- 1 ■^ .1 1 OO 1 1 oo :3 ' i 1 O 1 O t ' ' C^ 1 t CO '^'S II* 1 1^' I cT* * • ; ' ; eo' I ! Oi S I 1*1 It 1 '^ 1 1 CM C^ lO II 1 t^ . ^^co-* r^ OO OC^ -* OOOO i-H 11 « 05 (U 1 CO r^ 1— lO -^^ C5 -^ 05 1-^ r^ »o 1 " 1 to 3 ! -^'co'io co'm oo'-^'co'co'r--" •^"" I 1 I i—T 6©t^iO'-«r^ t-MO CI O CO c o I 05_ ^i^H ^ r-l ^rS* M co" a 09 a O •COr-.'-HMM 0'-«ClOM CO II 1 -^ g^ . 1^ 1-. Ci t^ t^ <0 O to CO M I^ » 1 ' CO . M '-1 »0 -rf M OO . 1 1 1 1 i a o O ; i i i :"iii;|l; : i i i i«ll iirs ; ; ; ; ;-2=-S :co-a3 o " o ' „- ° O ' ' ' ' ' I." o" I." ' S £i 3 ; ; ; o ao ,e;£kj ! ! 1 ,-c.2-c» t^ - i i i is : ■ ^5^ rt rf « 3 «^ C 2 2 S^ -2 1 rt-tiSt?99rt>«GCc:c:o302rtM«*r^ -ii 3 I- G^ o »-•— • PLATK U « A ^ 50 40 30 20 lb e 5 4 3 1 ^ 1 , >. 0.9 1 §^ ,« , . 06 It lo .10 ^ k 05 X.. 20 H^ fi 1 1 •4 ^5 S II ^^ «J jo .''' '^*^ — ^^^^ '■ Aret ■acre Price 0^ Corrrn ion t rick //7 ^J ilan^ per fpoi/s7na~^ ••^ ^^ •m.^ 1 \ •"^ ^^ -.^« ^_i ^_ __ -J4- '" 1 ^ \, ^ — k J — ■ \ ' Avei -a^e °rice of C emer. f in i io//>^r6 per \ barn r^. \ ^ / ^ / / ^^ •v. Ann ua/ \ 'firliJe 0^ Zemi 'nt-\ S. ^^._^ ~7 S ^^'**- -^....^ / 1 J k' "-. / • • "-x^ ^ »r^"** / V-- / An, 7ua/ Va/ue of 1. ■ a 'omn' 'r/ck 7on -''' > '-'' **"""• -—-"—' ^^' ^*fc y**-A/ '/7L/Cf/ / / Vcfiui ' of 'omr, 70/7 I ^nck SI/ 1 r' / ,' '•^.^ y / ,'■ / / ^^' A- Anm •a/ ^a /i/e 0. ■^ Ce. nenf / / COMMON BRIC Kand CEI^ ENT / \ y / STATISTICS OF CALIFORNIA 1896 TO 1926'' INCLUSIVE 7^ , / t 1^.03 0? / 1896 97 98 99 1900 01 02 03 04 05 06 07 08 09 1910 11 12 13 \A 15 16 17 18 19 1930 21 22 23 34 -25 26 1 i\'i\-i — rui-iMK iiiiy./ :;;; 32 o to" £ CM t- z U T-1 UJ 3 c CO < £ 0. z; 1- 9 .^ 1- 0; i _o 3 "5 W I ^ •o c c o a ^ ^ fc 1 (LAV IJKSOURCES AM) CKUA.MK' IXDUSTKV 3;] TABLE No. 3. Common Brick Production of California, by Years.* Production Av. value Year M Value per M ISyb 74,240 $391,567 ?6.H 1897 88.890 509,955 5.74 1898 108,076 598,823 5.54 1899 : 129,512 800,210 6.18 1900 119,906 698,583 5.83 1901 146,522 943,250 6.44 1902 181,040 1,291,941 7.14 19U3 217,715 1,600,882 7.35 1904 256,898 1,843,936 7,18 1905 284,205 1,961,909 6.90 1906 278,780 1,962,866 7.05 1907 339,439 2,483,062 7.32 1908 236,383 1,593,814 6.74 1909 276,396 1.749,209 6.33 1910 280,265 1,694,312 6.05 1911 282,199 1,716,442 6.08 1912 349,797 2,198,303 6.28 1913 295,729 1,699,426 5.75 1914 221,243 1,356,885 6.13 1915 160,452 981,888 6.12 1916 168,826 1,107,940 6.56 1917 169,045 1,207,765 7.14 i:tl8 96,732 912,205 9.43 i:tl9 126,892 1,545,558 12.18 l;(20 163,782 2,823,304 17.24 1921 202,417 2,880,124 14.21 1922 323,625 4,363,629 13.48 1923 397,754 5,194.527 13.03 1924 335,203 4,124,385 12.30 1925 297,449 3,317,766 11.12 1926 328,664 3,231,597 9.82 •Data prior to 1920 from U. S. Geol. Surv. Min. Res., since 1920 from Cal. State Min. Bui'can repf>rts. TABLE No. 4. Production of Pottery Clay in California in 1926. (From State Div. Mines and Mg. Bulletin No. 100, p. 97, 1927.) Ciiunty Tons Value Used in the manufacture of Alani(_-da 5,870 $7,183 Drain, faience, flood, quarry and roofing tile, sewer pipe. .A.mador 97,768 135,767 Architectural terra cotta, fire clay prod- ucts, chimney and sewer pipe, refracto- ries, drain, floor and roofing tile, and various. Ciiniia Costa 7,675 5,688 Architectural terra cotta, sewer pipe, faience and drain tile. Los Angeles a86,767 99,076 Architectural terra cotta, conduit, red earthenware, refractories, drain, faience, floor and roofing tile, chimney and sewer pipe, and oil well mudding. Monterey 491 1,164 Floor and roofing tile. Orange 13,150 38,989 Conduit pipe and stoneware, refractories, di-ain and roofing tile, and various. Placer 104,250 147,241 Arcliitectural terra cotta, chimney, .sewer and conduit pipe, drain,, floor and rf)of- ing tile, sanitary ware, red earthenware, and various. Jliverside 58,528 > 178,383 Conduit and sewer pipe, red earthenware, refractories, roofing tile, and various. .'^acramento 1,548 2,310 Crushed brick, faience tile, et al. San IJernardino __ ''2,268 10,605 Porcelain. San Diego '•130,187 58,269 Therapeutic clay, sewer pipe, faience, floor and roofing tile, and various. Santa Barbara ___ 1,100 1,700 Drain, floor and roofing tile. Ventura "373,000 93,250 Oil-well drilling mud. Butte, Calaveras, Humboldt, Mer- ced. San Luis Obispo, Santa Clara, Sonoma"* 18,859 26,884 Earthenware, porcelain, chimney and „ sewer pipe, drain and roofing tile. Totals 801,461 $806,509 * Combined to conceal output of a single operator in each. => Includes clay and shale for oil-well drilling mud. '' Includes kaolin. "■ Includes 'Cornwall' stone. * Includes therapeutic clay. 3 — 54979 34 DIVISION' OF MIXES AXD :MIXIX0 TABLE No. 5 Pottery Clay Production of California, by Years. (From Slate Div. Mines and Mg. Bulletin Xo. 100, i>. 98, 1927.) Year Tons Value Vear Tons Value 1887 75,000 $37,500 i:i07 160,385 $254,454 1888 75,000 37,500 IKOS 208,042 325,147 1889 75,000 37,500 1909 299,424 4G5,647 1890 100,000 50,000 1910 249,028 324,099 1891 100,000 50,000 1911 224,756 252,759 1892 100,000 50,000 1912 199.605 215,683 1893 24,856 67,284 1913 231,179 261,273 1894 28,475 35,073 1914 179,948 167,552 1895 37,660 39,685 1915 157.866 133,724 1896 41,907 62,900 1916 134,636 146,538 1897 24,592 30,290 1917 166.298 154,602 1898 28,947 33,747 1918 112,423 166,788 1899 40,600 42.700 1919 135,708 245,019 1900 59,636 60,956 1920 203,997 440,689 1901 55,679 39,144 1921 225,120 362,172 1902 67,933 74,163 1922 277,232 473,184 1903 90,972 99,907 1923 376,863 697,841 1904 84,149 81,952 1924 417,928 651,857 1905 133,805 130,146 1925 537,587 674.376 1906 167,267 162,283 1926 801,461 806,509 Totals 6.710.784 $8,442,643 TABLE No. 6. Value of Pottery Clay Products Made in California During 1926. (From State Div. Mines and Mg. Bulletin Xo. 100, p. 97, 1927.) X-imber of Product p.oducers Tons Value Architectural terra cotta 5 15,954 $2,361,524 Chimney pipe, terra cotta and flue lining 10 13,207 461,786 Drain tile 12 7.17S 113.168 Roofing tile 21 73.9S4 1.917,415 Sewer pipe 10 100.689 2.910,567 Ohinaware and semi-vitreous tableware 3 627,516 Sanitary ware 6 1,894.705 Red earthenware 6 198,308 Stoneware and chemical stoneware 6 434,772 Floor, faience, mantel, glazed and hand-made tile 27 2,867,772 Miscellaneous art pottery, bisque ware, brick dust, calcined clay, ceramic, mosaic wall tiles, conduit, conduit pipe, fire clay products, crushed brick and tile, garden furniture and pottery, high temperaturt- cement, porcelain, gas radiants, and backs, cast stone, ground clay, fire clay and grog, broken tile and various 23 837.670 $14,625,203 CLAY RESOURCES AND CERAMIC INDUSTRY 35 TOTAL ANNUAL VALUE OF CLAY PRODUCTS IN CALIFORNIA COM- PARED TO THE TOTAL FOR THE UNITED STATES. The figureis of the annual value of clay products, and the number of producers reporting are given in Table 7, for California and for the entire United States during the period from 1896 to 1926. inclusive. The ranking of California auu)ng the states, and the production of Cali- fornia as a percentage of the total United States production are also shown in the table. The production tigures are i)lotted on a ratio scale on Plate 111. Both the California and tlie United States curves may be conveniently divided into four time periods: (1) From 1896 to 1907, a period of rapid growth, during Avhich the United States ])roduction increased at an average of 8.7 per cent per year, whereas the California l)roduction increased at an average of 21.3 per cent per year. (2) From 1907 to 1915, a period of dei)ression following the financial panic of 1907, the effect of which was exaggerated in its influence on the common brick and hollow tile industry of California by the San Fran- cisco earthcjuake of April, 1906. During this period the average annual production of clay products in the United States remained nearlv stationary, while that of California showed an average annual decrease of 5.7 per cent. A contributing factor to this condition, both in California and in the United States at large, was the ra])id increase in the use of reinforced concrete, especially in the construction of large buildings in the major cities. (3) From 1915 to 1923, a period of rajiid expansion and rising. prices, but with a retardation of growth in 1917 and 1918 in the ])roduction of certain ceramic branches, such as architectural terra cotta, which were classed as nonessential and were unable to secure sufficient fuel or labor for maximum production, and a further period of retardation in 1921, following the post-war deflation that gained momentum in 1920. The latter effect is not noticed in the ceramic production of California. The average annual increase in the value of ceramic products in the United States during the eight year period was 12.7 per cent compared to 24.6 per cent for California. (4) From 1923 to 1926. Tlu' {)eriod is too short to permit accurate interpre- tation of trend, but a slowing down is apparent, both in California and in the United States at large. The average annual rate of growth of the value of ceramic products in the United States for the entire period of 30 years from 1896 to 1926 was 6.0 per cent, compared to 12.3 per cent for California. no DIVISION OF MINES AND MINING TABLE No. 7. California and Total United States Production of Ceramic Products from 1896 to 1926.* California United States No. Raik 'U uf Number of i>r(>- anijnji total of Years Value ducers states l^. S. value Value producers 1S9C $680,207 91 21 1.08 $6;',, 110, 408 629,3 1897 703,410 92 21 1.13 62,359,991 5424 1898 1,263,734 77 12 1.70 74,487,680 5971 1899 1,587,518 79 12 1.66 95,797,370 6962 1900 1,375,998 72 14 1.43 96,212,345 G375 1901 1,769,155 92 11 1.61 110,211,587 6421 1902 2,253,096 89 11 1.84 122,169,531 6045 1!I03 2,831,543 105 9 -2.16 131,062,421 6034 i:t04 3,624,734 121 8 2.77 131,023,248 6108 191)5 3,865,147 122 8 2.58 149,697,188 5925 1906 4,364,230 113 8 2.71 161,032,722 5857 1907 5,740,537 118 8 3.61 158,942,369 5536 1908 4,523,745 119 8 3.40 133,197,762 5328 1909 4,437,165 99 9 2.67 166,321,213 5068 1910 4,842,391 107 9 2.85 170,115,974 4915 lilll 4,915,866 92 8 3.03 162,236,181 4628 1112 5,912,450 91 8 3.42 172,811,275 4284 1913 5,344,958 91 9 2.95 181,289,132 4065 1914 4,461,661 84 10 2.70 164,986,983 3860 1915 3,599,375 83 10 2.21 163,120,232 3636 1916 4,163,426 79 10 2.01 207,260,091 3412 1917 4,826,125 74 11 2.10 232,512,773 3153 11)18 4,329,220 68 11 2.00 221,884,651 2783 1919 5,834,648 66 10 2.10 275,346,378 2776 1920 10,946,423 65 9 2.9 373,670,102 271G l!)21 11,172,491 63 8 4.1 270,738,536 2449 1>)22 14,689,830 62 6 4.6 321.494,403 2098 1923 20,833,053 86 6 4.9 424,582,628 2441 1924 20,994,732 86 (i 5.0 415,779,378 2353 1925 21,324,844 99 6 5.0 423,446,917 2417 1926 21,651,327 95 _ 4.6 459,049,470 2391 * Prom U. R. Geol. Survey prior to 1920. Since 1920 from U. S. Bur. Mines, Min. Res. CLAY RESOURCES AND CERAMIC INDUSTRY 37 Eh <: SdVllOQ JO SNOnilW o o o o iC o — cfddd It) § o o o o ooooo o 9bviioa JO SNioniiw 38 DIVISION OF MINES AND MINING Chapter III. CLAY DEPOSITS AND CERAMIC PLANTS BY COUNTIES. ALAMEDA COUNTY. General Features. Alameda County is on the eastern shore of San Francisco Bay and has a land area of 732 square miles, 500 of which are ricli agricultural bottom lands devoted to farmini>- and fruit growing-. The princijial cities are Oakland, Alameda and Berkeley. The population of the county is 344,177 (1920 census). The county is traversed in a northwesterly and southeasterly direc- tion by several mountain ranges, which together form the eastern grouj) of the Coast Range mountains. These ranges become rugged and reach higher altitudes in the southeastern portion of the county, their con- tinuation into Santa Clara County culminating in the ]Mount Hamilton range. The mountains consist largely of metamorphic sandstones, jaspers and serpentines of the Franciscan formation, together with sandstones and shales of Cretaceous and Tertiary age. The mineral resources of Alameda County include asbestos, brick, chromite, clay, coal, limestone, magnesite, manganese, potash, pyrite, salt, soapstone, and crushed rock, sand and gravel. The principal com- mercial mineral products in the order of their relative importance are : miscellaneous stone, salt, brick and hollow tile. Clay Resources. There are excellent deposits of common clay suitable for the manu- facture of common brick, hollow tile, and roofing tile at various places in the county, and a number of i)lants for manufacturing these products are in operation. The best and most extensive common clay deposits occur in the Livermore and Niles valleys. High-grade clays were at one time mined near Tesla, on the eastern edge of the county, but there is no present production. On account of favorable manufacturing and marketing conditions, a number of important ceramic plants have been established in the county, especially in Oakland, Alameda, Berkeley, Niles and Livermore, and a wide diversity of ceramic ware is produced. California Bisque Doll Companii. Mrs. H. T. Epperson, manager. Office and plant at 1175 San Pablo Avenue, Berkeley. Formerly the California China Company. This plant was built in 1906 for the manufacture of bisque doll heads, but there was no commercial output until 1919. It is said to be the only plant in the TTnited States produc- ing bisque doll heads on a commercial scale. A number of other ceramic products are made, such as salt and pepper shakers, art vases and bowls, and novelties. California raw materials are used whenever possible. The use of Clark and IMarsh kaolin from near Cali.stoga (samples No. ] 90-192, pp. 261, 280) is of special interest. The clays are prepared by small scale apparatus, and most of the shapes are made by casting. CLAY RESOURCES AND CERAMIC INDUSTRY 39 Fii"iii^' is (lone in safrgors in a small np-di'ai't kiln, firetl to cone 12 for biscuit ware, and to cone 7 to [) for the g:lost firin clays used are Lincoln No. 1-6 (sami)le No. 146. p. 303), lone sand (Shepard) (sample No. 128, p. 261), Valley Springs clay (samples No. 202-204, pp. 299, 337), a surface clay from Niles, similar 1o that used by the Niles plant of the W. S. Dickey Clay Manufacturing <'(). (sam])le No. 265, p. 343), and some Nigger Ilill clav from Calaveras County (sample No. 236, p. 263). The sewer pipe, chimney pipe, flue lining and garden pottery and 1 ile mixtures are prepared by dry-pan grinding, followed by wet-pan pugging. Sewer pipe is made in the usual presses. Chimney pipe, flue lining, and roofing tile are also made in a sewer-pipe press. Some of the roofing tile are hand finished, giving the appearance of hand- made tile. Floor tile, wall tile, and garden pottery are hand molded. Single-fire glazes are used. The clay mixture for stoneware is prepared by blunging, filter press- ing and pugging, followed by ageing for a suitable period. Most of the stoneware is jiggered. 40 DIVISION OF MINES AND MINING Diying is done iii a steam rack for the tile and stoueware, and other ware is dried on floors heated with waste heat from the kilns. Eight round down-draft kilns are used, fired with oil, atomized with steam. Two or three are 30-ft., four are 28-ft. and two are 25-ft. in diameter. Stoneware is fired to cone 8 (2400° F. on pyrometer) and other ware is fired to 2100° F. The average firing time is four days, making the total cycle 8 to 9 days per kibi. Sixty men are employed. In 1927, this company purchased the property formerly operated by the California Pressed Brick Company, and the plant was overhauled and newly equipped for the manufacture of brick and tile.^ Bibl : Cal. State Min. Bur., Bull. No. 38, p. 202 ; Prel. Kept. No. 7, p. 36. N. Clark and Sons. A. V. Clark, president and general manager ; G. D. Clark, secretary. Main office at 112-116 Natoma Street, San Fran- cisco. Plant at Pacific Avenue and Fourth Street, Alameda. This plant has been in operation since 1889. The principal products are architectural terra cotta, sewer pipe, fire brick and face brick. The company owns or controls deposits of all raw materials used in the body mixes at the plant. Sand and clay from lone (see under Amador County) and a calcareous shale from a deposit at Walnut Creek (see under Contra Costa County) are the principal materials used. The fire brick and face brick are made by the stiff-mud process, without repressing. Sewer pipe and terra cotta are made by the usual processes. Sixteen oil-fired round down-draft and muffle kilns are in use. Part of the plant was destroyed by fire in July, 1917, but was rebuilt in 1919. Another fire occurred on September 16, 1927, which caused a shut-down during reconstruction. Bibl : State Min. Bur. Bull. 38, p. 202 ; Prel. Kept. 7, p. 36. W. S. Dickey Clay Manufacturing Company: N. A. Dickey, manager. Office, 604 Mission Street, San Francisco. Plant No. 18 is one mile west of Niles, and was formerly known as the California Brick Company. Hollow tile and paving brick are manufactured. A Haigh continu- ous kiln is used for firing. Plant No. 19 is at Livermore, and was for- merly known as the Livermore Firebrick Works. Fire brick, fireclay refractories, face brick and sewer brick are manufactured. The management refused permission to publish data on the two plants, and as much of the data previously published by the Bureau is obsolete, there is no need for repeating it here. Bibl: Cal. State Min. Bur. Prel. Kept. No. 7. p. 35 (California Brick Company), and p. 37 (Livermore Firebrick Works). ElectHcal Porcelain Works. Levi S. Baker, proprietor; Joseph Baker and Chas. Ball, officials. Office and plant at 2414-16 Sixth Street, Berkeley. Electrical porcelain insulating products are manufactured, using English china and ball clays, Florida kaolin, San Diego County feldspar and silica, and lone and Lincoln fireclays. The ware is shaped by dry pressing, throwing, turning, machine-pressing, or cast- ing, according to the nature of the shapes to be made. Two oil-fired ' Clay -Worker, July, 1927, p. 36. CLAY RESOURCES AND CERAMIC INDUSTRY 41 kiln.s are used. One is 14 feet in diameter, and tlie other is 8 by 8 feet square. Hidecker Tile Company. G. C. liidecker, manager. The plant is at Twenty-fourth and Union streets, Oaldand, and manufactures roof- ing tile only. Local clay from excavations in Oakland and vicinity is mixed with Lincoln chiy (samjile No. 147, p. ;]03) and Natoma clay (samples No. 210 and 212, p. 337). A Williams hammer pulverizer is u.sed to disintegrate the clay, which is then screened through an 8-mesh screen, passed to a pug-mill, and finally to an auger machine, which is equipped Avith a hand-operated wire-cutter. The tile are dried on pallets in the open air. Two up-draft oil-fired kilns are used. The larger of these holds 25,000 eighteen-inch tile, and the smaller holds 12,000 tile. The water smoking is done with wood-shavings and requires 24 hours. This is followed by four days firing with oil, to a finishing temperature ranging from 875° to 980° C. Plight to ten men are employed during the operating season of five to eight months. Kraft Tile Company. A. Clay Myers, in-esident; J. L. Kraft, C. H. Kraft, E. Ridgeway, and II. E. Leash, directors and officers. General office, 55 New ^Montgomery Street, San Francisco. Plant at Pabrico, two miles west of Niles. This plant was built in 1926 to manufacture high-fired faience tile, using Lincoln fireclay and lone sand. Augers are used for shaping the tile. Hot-air driers of the deliydrator tyi)e are used for drying. After drying, the tile are carefully trimmed to size in a special machine before applying the glazes. This produces a finished tile that falls within closer limits of size than is customary in most plants. The product is fired in round down-draft kilns. The output of the plant in July, 1927, was 1000 square feet of tile daily. Miller's OaMand Art Pottery. ]\Irs. Isabelle Miller Burress, owner. Albert Van Cleve, manager, 2237 East Twelfth Street, Oakland. Sewer pipe, patent chimney pipe, flue lining, and drain tile are made at this ])lant. Yarn and Harvey clays (sam]>les No. 124 and 133, pp. 298, 302) from M. J. Bacon, lone, are used, together with excavation debris from Oakland and vicinity. The clays are prepared in dry and wet pans, and the ware is shaped in steam presses. Drying is done on the floors of the building, without special provision for heating by waste kiln gases. The firing equipment consists of five oil-fired round doAvn-draft kilns, the largest of which are 22-ft. in diameter and hold 35 tons of ware. The firing schedule varies from 48 to 72 hours, depending on the ware, and the finishinc- temperature averages 2000° P. (1093° C.) with a maximum of 2100° F. (1149° C). Twenty-five men are employed. Bibl: Cal. State Min. Bur., Bull. No. 38, p. 204 (Oakland Art Pottery). M & S Tile Company. Owned by F. J. Thomas, G. L. Smith and J. ]\I. Bettencourt. The plant is near the Oakland-Niles highway at Decoto. This plant was established in February, 1926, for the manu- facture of hand-made roofing tile. A local surface clay (sample No, 42 DIVISION OF MINES AND MINING 264, ]x 848) is used. Tlie clay is similar to that used in the W. S. Dickey Company's hollow tile i)lant at Xiles (sample Xo. 265, j). 843). The clay is mined -with the aid of a team and scraper. A small power- driven pug-mill prepares the clay for hand-molding. Drying is done on pallets under a shed. A rectangular oil-fired down-draft kiln, having a capacity of 5700 roofing tile, is used for firing. The firing schedule occupies 55 to 60 hours, and the finishing temperature is cone 06 (1005° C). Five men were employed at the time of visit, in September, 1926. Muresque Tiles, Inc. Wm. P. Muir, president and manager; Chas. Orpin, secretary; 1001 Twenty-second Avenue, Oakland. This is a small plant for making hand-pressed floor, wall and mantel tile, and decorative inserts. Lincoln and lone clays are used, which produce a buff or cream body. Matt glazes are used, which are buffed on a wheel after firing, producing effects similar to the well-known Batchelder tile, made in Los Angeles (see page 97). An oil-fired muffle kiln is used. No further details would be furnished by the company. RemiJUird Bn'cJi Company. C. Remillard, president; R. C. Giroux, secretary. Office, 332 Phelan Building, San Francisco. The plant is one and one-half miles northeast of Pleasanton, on the main line of the Southern Pacific Railroad. The plant was established in 1889 and has been oi)erate(l continuously since then. Common red brick are manu- factured. The clay deposit consists of a sandy loam, 25 feet thick, and is mined from a pit one-(iuarter mile from the plant by a drag-line scra])er oper- ated by an electric hoist. The clay is loaded into cars and hauled by motor to the i)lant. The soft-mud process is used. The brick are dried under sheds in the yard, and are fired in two 16-compartment Hoffman kilns, of 20. 000 daily capacity each. Fifty men are employed during the season. Bibl: Cal. State Min. Bur. Repts. XII. p. 381; XIII. p. 613; Bull. 38, p. 242 ; and Prel. Rept. No. 7, p. 37. Teclinkal Porcelain and China Ware Company. J. Pagliero, owner. Office and plant 420 Kains Avenue, Albany, via Berkeley. This is a small plant manufacturing porcelain bath-room fixtures by the cast- ing process from a mixture of California clays. One square up-draft kiln is used for both biscuit and glost firing. Four men are employed. Tesla: The coal and clay deposits of Eocene (Tejon) age in Corral Hollow, near Telsa, and extending for a short distance eastward into San Joaquin County, have been known since 1862. These deposits have been worked at various times in the past, notably during the ])eriod from 1897 to 1907. The coal was inferior in quality, and was costly to extract on account of steep dij) and swelling ground. As late as 1919 an attempt was made to reopen the coal mine, at which time the property was purchased by the Beckman-Linden Engineering Corpora- tion of San Francisco, and considerable sums of money were expended on equipment and development before it was clearly demonstrated that commercial success could not be expected under prevailing conditions. The principal activities in the past have centered around the Tesla CLAY RESOURCES AND CERAMIC INDUSTRY 43 M'ttii^ \ f 1 I i \ s * \ _ 'xV © ® } ® ' ® 9 ///" /a ^ t i ill 1 ] % 1 ]f\ p ■s.^ /-"' ^ s. 1 n ^ \ 2^ 4 \ •n !■? / I \ \ © ® 1 S 3 // In ® ""-- R ! /^ ill IL . II ^fi ii J f //' 1 1 .'-..,;/ \h /'" If Mh 'J7 ^-"-"'X^ >S ,en^ ^ '^ffMu^ crf/si" a o o U) c o o c ■5 H c 0) -a c ft '5 SI (U E^ a s 3 o u a o bo o o lioto Xo. '■^. Before usin, and "reuerally contains enough iron oxide to cause it to fire to a lifrht-ci-i'am coloi-, althoujih in ])laces it is sufficiently pure to tire to a satisfactory white coioi' for use in white-ware bodies. Several factors adversely affect the establishment of a financially-sound washing operation in the district, among which may be mentioned the c()m])aratively high freight rate to i)roducing centers, the low cost of IJelgiau saiul, which is delivered to California jjorts at a price of about $5 per ton, the low content of high-grade kaolin in most of the sands, and the fact that few important plants now using English or Florida kaolin would be willing to change to the use of local material unless as.sured of aji ample supply of uniformly high-grade kaolin over a long period of years. A new use for lone sand is in making white cement. One large company has recently bought a sand property, and it is anticipated that others will follow. The clays occur as a part of the lone formation and are distributed over a length of 12 miles and a wadth of 4^ miles in the county, with extensions into Sacramento County on the northwest and into Cala- veras County on the southeast. In most places the clays are covered by an overburden of soil, sand, tuff, volcanic breccia, and sandstone, varying from a few inches to a maximum of 20 feet over most of the depo.sits now being worked. The clay beds have a slight westerly dip. Lignite coal, interbedded with clay, is found at depths of 40 to 125 feet. The clay beds are not continuous, and the extreme limits of the i)robable boundaries of the deposits have not been determined, but enough mining and drill prospecting has been done to demonstrate the fact that there is an ample supply of clay for many years. The contemporary theory of the origin of the clays has been well summarized by Logan. ^ "The white clay apparently came from the rhyolite ash flow.s, which have been found directly over the older series of gold-bearing gravel channel.s in the Sierra Nevada. Probably a long enough i)eriod of erosion ensued after these initial ash outljursts to ])ermit the carrying of the finer sized and lighter particles down the streams into the shore waters of the inland sea which then filled the Sacramento and San .Toaquin vallejs. P.efore the white ash was covered and jircserved by later flows of darker colored lireccia and ash, a large i)art of it was thus swept away. "That the clay is of rhyolitic origin, possibly mixed with the quartz sand from those mysterious earlier rivers whose remaining sections now show such a remarkalile amount of quartz cobbles, with scarcely any other rock, is substantiated by the analyses. The sandy clay carries about 70% silica, 20% alumina. 1.25% iron oxides, 0.3% CaO, and 0.2% MgO. Other samples where the p<»rcentage of silica is less, contain 32% to 34% dry weight of alumina. The amount of calcium is typically low and it is erratically distributed, sometime.s as gypsum seams. As the percentage of iron increases the clay becomes mottled red and yellow, but the usual color is white, cream or light lilue." Arroyo Seco Grant. Introduction. The greater part of the lone clay deposits lie within the boundaries of the Rancho Arroyo Seco, which was formerly owned by the McKis- sick Cattle Company, who leased many of the clay deposits to Bacon & Bacon (see post) and other operators in the district. In 1926 the grant was purchased by S. E. Kieffer, 57 Post Street, San Francisco, ' Op. cit., p. 135. 52 DIVISION OF MINES AND MINING who then leased the clay j^roperties to G. A. Starkweather. ]\Ir. Stark- weather is operating some of the properties, but has subleased a num- ber of them to various ojierators. A map of tlie prant, and of the surrounding pro])erty, sliowiufj- the location of tlie i)rincipal clay deposits, is sliown on plate VI. Core Drilling. Durin riiiles by road south of Wallon siding, on the Amador Central Railroad. Photo No. 10-A is a view of this pit, taken on August 8, 1925. The strip])iiig of loose sandy and gravelly soil attains a maximum thickness of 2U feet in the present pit, but will gradually increase as mining operations advance northward. Two varieties of clay are differentiated. The upper bed (sample No. 141), six to ten feet thick, is a yellowish fireclay, containing occasional iron stained boulders. This is underlain by at least 15 feet of hard blue-gray plastic clay (sample No. 142), which at the time of visit was not in use. The results of tests on these varieties are given on i)age 280. The method of mining ])revious to 1927 is clearly illustrated in the pliotograph. Hand picking and light blasting was used to loosen tlie clay from tlie bank, wliere it was picked up by a tractor-drawn scraper, dragged up an incline, and dumped into a hopper over the tunnel, Photo No. 10-A. Fancher clay pit, Jackson Valley, near lone, leased by W. S. Dickey Clay Mfg. Co., facing northwest. (In 1925.) (Samples No. 141 and 142.) from which it was delivered to an auto truck. A one-ton Ford truck is used for hauling the clay to Wallon siding. Beginning in 1927, the thickness of overburden has been such that the mining method was changed to tunneling. Eckland Property. Mrs. C. Eckland, 1743 N. Hunter Street, Stock- ton, owner. This property consists of 80 acres, lying to the south of the lone-Jackson highway at the point where it crosses the railroad, 1.5 miles ea.st of lone. The property is at present (1927) idle, but was at one time worked by Mr. Dennison of lone. Yellow, i)ink, and red-mottled plastic clays are exposed in the walls of the abandoned pit, from which sample No. 213 was taken (see page 299). \Vm. Haver- stick of lone supplied a .sample (No. 209, p. 263) of white sandy clay from a 16-foot drill hole on the southwestern portion of the property. Almost the entire property is covered with an overburden of volcanic 60 DIVISION OF MINES AND MINING breccia, and insufficient i)ros|)ecting has been done to determine tlie extent and character of the underlying clay beds. lone Fire Brick Co., J. T. Roberts, president and general manager, 12 Russ Building, San Francisco ; Wm. Brown, superintendent at lone. The lone Fire Brick Co., a subsidiary of the Stockton Fire Brick Company, is located about two miles southeast of the town of lone, on a spur track of the Amador Central Railroad. JNIachine-made fire brick are made, using a mixture of Lincoln clay, now secured from the pit of the Clay Corporation of California at Lincoln (sample No. 280, p. 305), and lone clay, sand (sam])le No. 140, p. 280), and grog from pits near the plant. Photo No. 10-B. Brick machinery in plant of lone Fire Brick Company. (Photo by courtesy of the company.) The mixture is prepared in a dry pan and pug mill, shaped in an auger machine, wire cut (side), and repressed. Drying is accomplished in air under sheds and in the open. Only such standard shapes as can be made on the auger machine are manufactured at this plant, there being no hand molding. Photo No. 10-B is an interior view of the plant, showing an auger machine and two re])resses, with off-beai'ing con- veyors. The firing equipment consists of five oil-fired round down-draft kilns, having a total capacity of 11,000 brick per day. The auger machine capacity is 20,000 brick ])er day, which makes it possible to prepare a sur])lus for storage to be fired during the winter months, when clay mining can not be economically carried on. CLAY RESOURCES AND CERAMIC INDUSTRY 61 Groc: Groo; for use in llic phiiil of llic lone Fife liriek Company is mined fi"om a small i)i1 adjoining- the Uacon I'ed day i)i1. A six to twelve foot bank is exposed, over a len«rtli of 100 fi'et. 'Phe material consists maiidy of i)artly-rounded (piarl/ <>ravel, most of Aviiieh is under two inches in diameter. The interstices are partly filled with fine sand, with a small amount of clay, li'on stainin«>' is a ])rominent macroscopic feature, but the total iron content is not too high to permit the production of .second-j>rade fire brick when used as the sole grog constituent. Sand: The sand ])it of the lone Fire Brick Com])any is lu'ar the grog pit and is shown on photo No. 10-C. May E. Xewnum Estate. "Slain otYice, 980 lUish Street, San Fran- cisco. The pit is on a 150-acre proi)erty in Sees. 20, 80, and .'U, T. 6 N., I\. 10 E., M. D. M., on the Amador Central Railroad, one mile south- west from lone, and less than a half mile northeast from the plant of the lone Fire Brick Co. The bulk of the output from this property up to date has been lone sand, but plastic red clay beds have been found, and a small amount has been shii)])ed. The main sand pit abuts the railroad tracks on its eastern boundary. The sand occurs in two separate beds each 10 to 15 feet thick and separated by a bed of carbonaceous sand from 6 to 30 feet thick. Volcanic breccia of variable thickness overlies tha deposit. Open-pit mining was used at first, but practically all of the sand not covered by volcanic breccia has by this time been removed, and ])resent mining is by underground methods, using the room and pillar method. The general plan of mining, M'henever a systematic lay-out is possible, is to drive rooms in the bottom of the upper bed approximately 10 by 10 feet in cross-section on 25 foot centers to the limit of the block of ground being mined, usually about 250 feet, then retreat by excavating to the roof, and by cutting across to adjacent rooms, finally reducing the j^illars to a])])roximately six feet in diameter. The sand is loaded by liand into small cars, which are dumped into a loading chute at the entrance of the mine. The loading chute delivers to mine cars which are in turn hauled up an incline and out of the pit by a car hoist, finally delivering the sand to a loading bin on the railroad siding. Some of the lower sand bed has been mined and shipped from places where it has been exposed by open-pit mining. The present underground method does not leave the mine in a satisfactory condi- tion for the recovery of the low^er bed in the future, unless the capping of volcaiiie breccia can be utilized as grog, and the bed of carbonaceous sand is strip]ied. Seven or eight men are employed during the dry months, when an average of 9 cars per week is ship])ed. The annual output varies with demand, and is normally in excess of 6000 tons. Since the above was written, the property was visited in 1927 by Mr. Logan, from whose report' the following additional notes are taken : "The old pits, operated for years south of the track, have been worked up to the property line. A new i)it has recently been started on the north side of the track. In vertical section, so far as opened, it shows from top to bottom 2.5 feet of over- burden 10 feet of red mottled clay, and 15 feet of white sand. The red mottled clay now being shipped for testing (April 13) is said to carry a little more sand than the iAcon mottled clay. Nine men were employed on that date. Clay is mined by hand m an open pit and hauled in a small truck to the railroad cars, a few hundred feet away. It is thought this clay will prove suitable for tile. The white sand is stated to run 71% silica. If regular production starts, drifts will be .run to avoid handling the overburden." 1 State Mineralogist's Rep. XXIII, p. 141. 62 DIVISION OF MINES AND MINING CLAY RESOURCES AND CERAMIC INDUSTRY 63 Three samples were taken from tliis property. No. 129 is sand from the upper sand bed, taken from the nnderjifround -workings at the Avorking face when visited on August 8, 192,"). The test results are given on page 2()1. Sample Xo. ].'}() is representative of the carbonaceous sand, and was taken with the object of studying possible uses. The test results, page 2!H), on tlie untreated sand were nnfavoi-abh'. and is unlikely that beneficiation, even if proved possible, would be of com- mercial importance in the immediate future. Sample No. 131 is from the deposit of red clay from the new pit, and is seen (p. 329) to be quite similar in its jiroperties to the Bacon red (sample No. 127. p. 335). Yosemite Portland Cement Company.^ Main office. Pacific Building, San Francisco. This is known as the Harvey ])it and is part of over 100 acres of land recently purchased from Fred Harvey. The pit is just east of the old Ilarvev coal mine, and one mile north of Carbondale. The land is in Sees. 32, 33 et al., T. 7 N., R. 9 E., M. D. M. Bluish fireclay occurs with an overburden of from two to three feet of soil in which are found concretionary boulders of red iron oxide. The pit was formerly operated by hand methods, but in 1927 a jViow and scraper, drawn by a tractor, were used for removing the over- burden, and the clay was mined by a small steam shovel. The pit is now about 12 feet deep, and it is stated that borings have indicated a depth of 65 feet of clay, over an extensive area. Auto trucks are used to deliver the clay to the railroad. The clay contains about 32% alumina, dry basis, and is used in the manufacture of white cement. It is also a useful sewer pipe and terra cotta clay. Sample No. 133 Avas taken for test. The results are given on page 298. Changes Since Former Reports. The following important changes have occurred in the Amador County clay industry since the publication of Preliminary Report 7, and the Nineteenth Report of the State Mineralogist : Amador Kaolin Company. Extinct. W. D. Amirk Property (formerly operated by the Philadelphia Quartz Co.). A white sand deposit containing from 20% to 30% of kaolin. A washing plant was built and operated during the World War. Now dismantled and idle. McKissick Cattle Company. Former owner of Rancho Arroyo Seco, now ow^ned by S. E. Kieffer and leased by U. A. Starkweather, as noted, ante. Newman Clay Company. Now ]\Iay E. Newman Estate. Philadelphia Quartz Company. No longer operating in the county Bibl. of lone district : Cal. State Min. Bur. Report XIV, pp. 5-11 ; XXIII, pp. 134-144. Bull. No. 38, p. 206. Prel. Rept. No. 7, p. 38. ' Logan, C. A., op. cit., p. 138. (Under Pacific Poi-tland Cement Company, Con- solidated.) 64 DIVISIOX OF MINES AND MINING BUTTE COUNTY. General Features. Butte County is in the north-central jiortion of the state, lar Lindgren, Waldemar. The Tertiary Gravels of the Sierra Nevada of California : Prof. Paper 73, U. S. Geol. Survey, p. 86, and Plate XV, 1911. CLAY RESOURCES AND CERA^MIC IXDTTSTRY 65 l*lacer County, but the new (■iit('r])i'isc of the Natonia Clay Co., at Xatonia. Sacramento County (see path 100 ft." Also, "* * * a deposit of light-colored clay, more plastic than above in XEj, Sec. 13." This would lie one mile north of Pentz. A recon- naissance of this section was made, without finding any material of value. Most of the section is covered with Tuscan tuff. The lone for- mation outcrops to the south, and disappears under the Tuscan tuff. Garden Ranch. SWj Sec. 22. T. 19 N., R. 3 E., 3 miles southeast of Oroville. "Extensive deposits exposed in road building." No material of value could be found on this area. Snow Ranch, Lovelocks. SWj Sec. 31, T. 24 N., R. 4 E., "Light- colored clays of medium plasticity." A reconnaissance of this locality was made, and nothing of interest was found. Some partly kaolinized diabase ( ?) occurs in ])laces, but is badly contaminated with iron. The region is too inaccessible to be of economic importance as a producer of any but the finest grades of clay. CALAVERAS COUNTY. General Features.' Calaveras County lies on the west slope of the Sierra Nevada Moun- tains, the elevation ranging from 400 feet above sea level, where it joins San Joaquin County on the west, to 8000 feet where the eastern bound- ary rests on the summits of the Sierras adjoining Alpine County. Bounded on the north by Amador County and on the south by Tuolumne, it shares with them the advantage of a climate where snow seldom falls and practically never lies below 2500 feet elevation, and where mining may be carried on throughout the j'ear under ideal weather conditions. Water, power, and timber resources are plentiful. Several railroad branches connect the main towns with points in the San Joaquin Valley. Most points in the county at elevations under 2500 feet can be reached by automobile during the greater part of the year. The principal mineral .products of the county are gold and copper. Other minerals that have been produced are silver, produced as a by-product of gold and copper mining, limestone, mineral paint, clay, mineral water, asbestos, rock crystal (quartz), chromite, and miscel- laneous stone. 'Prom Logan, C A., Calaveras County: State Mineralogist's Report XXI, p. 135, 1925. 68 DIVISION OF MINES AND MINING Geology. The geoloyy of the county is similar to that of Amador County and others in the Mother Lode belt. The lone formation (Eocene) is found at numerous places, but is not so extensively developed, nor so well pre- served as in Amador County. The following is a portion of the geological summary of the county as given by Logan :^ "The Neocene shore-line, as Indicated by the lone formation, covered the county from Lancha Plana through Valley Spring to .Jenny Lind, and southward to Milton. The most westerly of the lode mining districts are the Hog Mountain-Gopher Range cojiper mining district, where copper ores occur in diabase and allied rocks, near the southwest corner of the county, and the Campo Seco copper district, where similar ores occur in amphibolite schist. In a depression called Salt Spring Valley, between the older crystalline rocks of Gopher Ridge and Bear Mountains, lies a belt of black Mariposa slate with interbedded lenses of ami)hibolite, with important copper deposits, which conform in strike with the direction of schistosity of the enclos- ing rocks. The Mother Lode belt of black Mariposa slate enters the county at Middle Bar, but aside from the Gwin Mine, which had reached a depth of 2Sr)0 feet before it was closed several years ago, little deep mining has been done in this district, though numerous quartz mines have been opened to depths of less than 1000 feet. There are many ijrominent veins in the granodiorite area of Mokelumne Hill, but the main belt passes southeast, a line of Assuring having passed into the amphib- olite schist, in which rock were found the deep mines of Angels Camp and Carson Hill. "The East Belt is a general name given to the gold-quartz mining districts in the great body of Calaveras (Carboniferous) rocks, lying east of the younger Mother Lode slate and east of the amphibolite schists accompanying the Mariposa slate. The Calaveras rocks are chiefly hard blocky siliceous and micaceous schists, quartzite, curly black slates and accompanying intrusive dikes, usually of basic character." Clay Resources. Various clay deposits in the lone formation near Valley Springs and Helisma have been operated in the past. Some work has been done recently on a deposit of kaolinized talc schist in the Calaveras (?) formation. The California Pottery Co.y of Oakland and IMerced, own two deposits in Calaveras County, one at Nigger Hill, and the other at Valley Springs. Henry Ward of Vallej^ Springs is superintendent. Nigger Hill : Near Nigger Hill, about three miles north of Valley Springs, a good deposit of white-burning kaolinized sericite schist has been discovered. A tunnel has been driven for 250 feet. The kaolin- ized zone is from 15 to 25 feet thick. The material has low plasticity, but is of use as a filler in white tile bodies. Sample No. 236 (p. 263) was taken at the face of the tunnel, and Sample No. 237 (p. 263) was taken at the portal. Valley Springs Clay Pit : This pit is ^ mile northwest from Valley Springs on a spur track from the Valley Springs branch of the Southern Pacific Railroad. The property comprises 17 acres. Fireclay from the lone formation is mined from an open pit, shown in photo No. 11. Two distinct varieties of clay are mined and shipped to the Merced plant of the companj'. One of the.se is classed as 'pink mottled,' (sample No. 202. ]). 337), and the other is 'yellow' (sample No. 203, p. 337). The two varieties are somewhat intermingled, but can be separated by hand as mined. In the southern end of the pit, northward to the break in the face shown in the photo, the pink mottled predominates, and in the northern end of the pit, the yellow variety is more important. Some yellow sandy streaks traverse the clay, and in places small quantities of white claj^ are found. ' Ov. fit., p. 140. CLAY RESOURCES AND CERA:MIC INDUSTRY 69 The floor of the pit is approximately 200 ft. square, and the face varies from 10 to 30 feet high. The clay is loosened by hand drillinp; and light blasting, and is loaded by hand shoveling into ■wlicolbarrows, "which are dumped into a hopper. An inclined belt conveyor trans- ports the clay from the hopper to a railroad car. In a test pit five feet deep, just east of the track, ])ink mottled clay is exposed. Fifty feet farther east another test-]iit was snnlc, Avitli the aid of a Avindlass, to a doptli of 25 feet. Uoth i)iidv-mottled and yellow clay were found to the bottom of the shaft. From the debris surround- ing the collar of the test-pit it was estimated that the pink-mottled variety comjirised about one-third of the material excavated. A third 25-ft. test pit was dug 100 feet north of the second one, and similar material was encountered, in addition to a bluish-white plastic clay, not entirely free fioin liiiionitie stains (sample No. 204, p. 299). This Photo No. 11. Valley Springs clay pit (California Pottery Co.), facing west. The track runs S. 25° E. The 5-ft. test-pit appears in the center foregi-ound. (Samples No. 202-204.) test-pit was bottomed in a yellowish sandy bed. From the evidence on the dump, the bluish-white variety of clay predominates at this point. It is evident that the total thickness of useful clay is in excess of 50 feet, and the structural and topographic features are such as to warrant the expectation that these beds underlie an area of many acres. Three men are employed during the operating season. In 1925, nearly 200 cars were shipped, at the rate of approximately four cars per week. Helis'tna Fireclay Depo.'iif. One-quarter mile north of Helisma (formerly Burson) station on the Valley Springs branch of the Southern Pacific Railroad is an abandoned fireclay pit formerly controlled by W. A. Houts, 202 Balboa Building, San Francisco. The present ownership of the property was not determined. The deposit is in the lone formation. The total thickness of clay exposed in the pit varies from 8 to 15 ft. The upper part of the clay bed is a bluish-white clay with good plasticity, and the lower part is a 70 DIVISION OF MINES AND MINING greenish-white clay, with less plasticity. Both varieties of clay are traversed by thin limonitie seams a foot or more apart. The main pit is 150 ft. lonp:, 50 ft. wide and from 8 to 15 feet deep. The overburden, of volcanic breccia, increases from a few inches at the lower edge of the pit to 10 ft. at the upper edge. Two hundred feet to the west is a smaller pit 80 ft. long by 30 ft. wide, and a maximum of 10 ft. deep. The clay is similar to that in the larger pit, but contains more iron, and is more sandy. The clay was formerly worked by hand loading into cars which were hauled up a gentle incline to a loading chute overlooking a railroad siding. All equipment has been removed from the property. The probable extent of the clay bed beyond the existing exposures could not be determined without boring, on account of the overburden. Structural features are favorable to a continuance of the clay under the low hill on which the pit is located, but the overburden covering the top of the hill may be 20 ft, or more in thickness. Sample No. 201. page 305, includes both types of clay from the main pit. Bibl : Cal. State Miu. Bur. Prel. Kept. No. 7, p. 43. Pcnn Mining Co. During the operation of the copper smelter at Campo Seco, a kaolinized sericite schist overlying the copper beds was used in the smelter as a refractory. Since the smelter was closed down this material has not been utilized. The locality was visited on Septem- ber 22, 1926, and a sample was taken from the abandoned open cut from which it was formerly obtained. The sample is Xo. 238 and the tests demonstrate that the plasticity and strength are low, and that the content of fluxes is high, causing fusion to begin at cone 9 (1285° C). See page 316. Bibl: State Min. Bur. Bull. 38, p. 211 ; Prel. Kept. 7. p. 43. Texas Mining Compan}/. J. P. Hoskinson, Valley Springs. This is an undeveloped property about two miles north of Valley Springs. Small exposures of sandy fireclay belonging to the lone formation have been found, and some prospecting has also been done on an outcrop of kaolinized sericite schist of Calaveras (?) (Carboniferous) age. Sample Xo. 233 was taken of the fireclay, but was not tested, as the quality was obviously poor, and the continuity of the deposit is doubtful. Sample No. 234 and 235 were taken from two different exposures of the kaolin- ized schist. The test results of X"o. 235 are given on page 263. It is a white-burning refractory material of low plasticity, that would be useful as a filler in white ceramic bodies. X'^o. 234 wa.s not tested, as it is similar to No. 235. COLUSA COUNTY. General Features. Colusa County lies on the west side of the Sacramento Valley. The west side of the county is in the foothills of the Coast Range, and the east side is in the basin of the Sacramento Valley. The area of the county is 1140 square miles, and the population is 9920 (1920 census). Colusa is the county .seat and principal town. The mineral resources of (^olusa County are largely undeveloped. Occurrences of coal, chromite, copper, gypsum, manganese, mineral CLAY RESOURCES AND CERAMIC INDUSTRY 71 •water, ])yrite. ciincksilver, sandstoni', iiiiseellaneous stone, sulplnir. and in some places, di-y i)ressing, following dry-pan preparation of the clays. Photo Ko. 13. Richmond I'lessed Urick Co. plant, with clay pit in background, Richmond, Contra Costa County. (Sample No. 11 'J.) (From State Miner- alogist's Report XXITI, p. 8, 1927.) The firing equipment consists of six 36-ft. round down-draft kilns, using oil, atomized by compressed air. The red-burned ware is fired for nine days to finishing temperatures corresponding to cones 09 to 07 (930° to 975° C), and the buff face brick and fire brick are fired to cones 7 to 9 (1210° to 1250° C.) in seven days. The kilns are equipped with pyrometers. Electric power is used to operate the plant. Fifty-five men are employed. See sample No. 119, page 325. Standard Sanitary Manufacturing Company. The Standard Sani- tary Manufacturing Company of Pittsburgh, Pennsylvania, purchased the plants of the Pacific Sanitary ^Manufacturing Company in 1926, and have since constructed a new sanitary porcelain plant, known as Pacific Pottery, to replace two smaller plants formerly operated by the Pacific company. The Standard company is also continuing the operation of 76 DIVISION OF MINES AND MINING the enameling plant, now known as the Pacific Enamel Works, formerly owned by the Pacific company. These plants are in Richmond and San Pablo. F. A. Kales, Box W, Richmond, is general manager. The two plants manufacture a complete line of porcelain and enameled sanitary ware, except porcelain bath tubs. Both plants are modern in every respect, and are designed for economy of production and close control of manufacturing methods to ensure uniformity of quality. Two tunnel kilns were installed in the new porcelain ])lant. It is against the policy of the company to permit ])ublicati()n of details regarding the plant equipment and operation. Bibl : State Min. Bur. Prel. Rept. 7, p. 44, 1920. Extinct Companies. Among the former brick companies that have ceased operations in the county are : Mt. Diablo Pottery and Paving Brick Co. Carquinez Brick and Tile Co. Coast Firebrick Co. Holland Sandstone Brick Co. Diamond Brick Co. Golden Gate Sandstone Brick Co. Richmond Brick Co. Gerlack Brick Co. DEL NORTE COUNTY. General Features. Del Norte County, in the northwest corner of the state, is without rail connections, and is dependent upon light-draft vessels docking at Crescent City, auto stages, trucks, wagon and pack trains for trans- portation. Lumbering is the principal industry. ITnder such condi- tions, and with a population of less than 3000 (1920 census), the demand for clay products is so small that practically no clay industry has been developed, and no deposits of high-grade clay have yet been found that will warrant mining and shipment to outside points. The geology and the physiographic features of the county have been well summarized by Laizure : ^ "A low costal plain, three to five miles in width, extends from the vicinity of Smith River to a point a few miles south of Crescent City. East of and surrounding this area of Quaternary formations and extending- from the Oregon line through Del Norte and south into Humboldt is a belt of Franciscan rocks, mainly sandstones and shales. The eastern boundary of this belt crosses Smith River just west of South Fork, and its contact with the succeeding zone of metamorphic and eruptive rocks marks the line between the Coast Range and the Klamath Mountains. This succeeding zone of metamorphics also extends through the county from north to south, widening out toward the north, where its width is about 15 miles. It is composed mainly of serpentine with unaltered masses of peridotite and many inclusions of 'diorite,' more or less altered. This belt is mineralized and most of the deposits of gold, copper, chromite, and platinum are associated v\ith it. Between here and the eastern bound- ary there is another narrow belt made up largely of Franciscan schist and slate, intruded by deep-seated igneous and volcanic rocks. Serpentine again predominates along the boundary and extends over into western Siskiyou County." Clay Resources. Deposits of common clay suitable for brick manufacture occur at several points within a short distance of Crescent City, especially in ^Laizure, C. McK., Del Norte County: State Mineralogist's Report XXI, p. 282, July, 1925. CLAY RESOURCES AND CERAMIC INDUSTRY 77 Elk Valley and along the Smith River. A small brick yard, ^vitll a wood-tired kiln, was at one time ojx'rated by licnjmnin llowbind, wlio used clay from the ]Musiek i)roperty. in P]lk Valley, 4.8 miles from Crescent City.' There is said to l)e a deposit of good pottery clay in Elk Valley,- hut this could not be verified in the course of the present investigation. Musick Properixj. This proi)efty lies ().:{ nule north of the Elk Valley road, from a point 4.5 miles from the center of Crescent City. The pit, now abandoned, is 25 feet in diameter, and three to four feet deep. A laj-er of black soil, less than one foot deep, overlies a yellow plastic clay, of unknown thickness and lateral extent. Sample No. 180 was taken from this deposit. The test results are on page '-Vl^. FRESNO COUNTY. General Features.' Fresno is one of the southern counties of the San Joaquin Valley. Madera and Pierced counties are on the north, Mono and Inyo on the east, Tulare and Kings on the south, and San Benito, Monterey and San Luis Obispo on the west. The area of the county is 5977 square miles, or nearly three times that of the State of Delaware. The population is 128,779 (1920 census). The San Joaquin River separates Fresno from ]\Iadera County, and the eastern boundary runs along the summit of the Sierra Nevada Mountains. Along this line are nnmemus peaks exceeding 1:^,000 feet in elevation above sea level. Adequate transportation is provided throughout the populous sec- tion of the county by two railroads — the Southern Pacific and the Santa Fe — each of which has many branches to important points. Power and water facilities are well provided for mining, industrial, and agricul- tural i)urposes. The ])rincipal wealth of the county is in agricultural products, and the greater i)art of that portion of the county lying in the San Joaquin Valley is under cultivation. The most important mineral i)roduct is petroleum, the bulk of which is produced from the Coalinga field, and is responsible for placing Fresno County sixth in importance as a mineral i)roducer among the counties of California. Miscellaneous stone is of secondary importance. Other commercial products are nat- ural gas, granite, brick and hollow tile, gold and silver, and mineral water. Comparatively little mineral development has been done in the mountainous portion of the county, but occurrences of many useful minerals other than those noted above are known, among which are asbestos, barytes, chromite, copper, gems, graphite, gypsum, limestone, magnesite, marble, quicksilver, and tungsten. Clay Resources. No commercial deposits of high-grade clays have been discovered in the county. The alluvial silts of the San Joaquin Valley have been utilized for numy years for the manufacture of common brick and hollow tile. There is, however, a scarcity of common clay of suitable plasticity for this purpose, and it has often been necessary to ship in ' State Mineralogist's Report XIV, p. 379, 1913-14. - Idem. = See State Mineralogist's Rept. XIV, pp. 429-432, 1914. 78 DIVISION OF MINES AND MINING small (|iiantities of this material to the brick yards from distant points. Two brick plants are at present (1927) in operation, one of which makes hollow tile and face brick in addition to common brick. Craycroft-HcroJd Brick Co. F. J. Craycroft, president, 407 GrifSth- McKnig"ht Building-, Fresno; Wm. Turner, vice president and superin- tendent. The plant is located at Crayold siding three miles west of Fresno. The products are common brick, ruffled and plain face brick, and hollow tile. Some of the clay used in the plant is from a superficial valley deposit of plastic clay 6 miles south of Merced. The deposit is mined to a depth of 14 feet, and one car (50 tons) per day is used to mix with a local clay from a pit near the plant. The local clay is mined to a depth of five feet with a horse scraper. It is a valley silt, with insufficient plasticity to be used alone. The plant is equipped with a 9-ft. dry i)an and revolving screen for preparing the tile mixture, and a No. 4 Williams pulverizer for the brick mixture. The ground mixture is elevated to bins from which it is fed to the pug-mills by automatic feeders. An American No. 2 auger is used foi" tile, and an American No. 4 auger with a Freese cutter shapes the brick. Drying is generally under sheds, as under the pre- vailing conditions the waste heat drier with which the plant is equipped has insuf^cient capacity, and o]ierating costs are higher than open-air drying. In the summer, when the atmosphere is hot and dry, the ware is dried in about seven days. The face brick are fired in three 38-ft. round down-draft kilns. Common brick and hollow tile are fired in field kilns, having a capacity of 950,000 common brick each. The fuel is oil, atomized wuth steam. The firing period is 7 days, to a temperature of 1900° F., followed by 7 days cooling. Pja-ometers are used to control the temperature of the down-draft kilns. The capacity of the plant is 56,000 brick and 6,000 hollow tile per day. Electric power is used throughout the plant. Bibl: State Mineralogist's Report XIV, pp. 433-434; Bull. 38, p. 242. Pioneer BricTc and Tile Company. T. W. Hasty, president and manager; Arthur Bentley, superintendent. Address P. 0. Box 614, Fresno. The plant is at California and Peach avenues, south of Fresno. Common red brick is the only product. A local valley clay is used, and it is mined to a depth of five feet with a Bay City gasoline shovel. Hardpan underlies the clay. The clay is delivered to a Potts disintegrator, from which it is carried by a belt conveyer to a pug-mill, followed by a Bonnett auger, equipped with a Freese cutter. The brick are dried in sheds, requiring from seven to ten days. Three open kilns are in use, fired with oil, atomized with steam. The kilns have a capacity of 1,060,000 brick each. The firing period is 5^ to 6 days, to a maximum temperature of 1550 to 1600° F., and cooling requires 4 to 5 days. One and one-half barrels of oil are used per thousand brick. The capacity of the plant is 40,000 brick per day. Electric power is used for all machinery. CLAY RESOURCES AND CERAMIC INDUSTRY t)f GLENN COUNTY. General Features. Glenn County lies on the west side of Sacramento Valley, north of Colusa, and south of Tehama. Its area is 1259 scpiare miles, and the population is 11,8;53 (1920 census). Willows is the i)rincipal town. The western portion of the county is in the foothills of the Coast Range, and the eastern portion is in the basin of Sacramento Valley. In tlie foothills, deposits of chromite, coi)per, mang-anese, sandstone, and soap- stone have been found. The only couuucrcial mineral production in recent j^ears is of sand and lii-avel. Clay Deposits. Brick clays are abundant, especially in T. 19 and 22, R. 8 W., M. D. M. The clays are chiefly sandy loam. No brick have been made since about 1895, but several yards Avere operated near Willows previous to that time. Bibl : State Min. Bur. Bull. 38, p. 243. HUMBOLDT COUNTY. General Features. Humboldt County, of which Eureka is the county seat and principal town, is on the north coast, between Del Norte and Mendocino counties. Althoup^h the harbor facilities at Eureka are excellent, the progress of the county was slow completed through to Eureka from the south. The greater part of the country is rugged and mountainous. The ridges and spurs of the Coast Range traverse the county in a north- westerly direction, roughly paralleling the coast line. The coastal plain is narrow and along the greater part of the coast line is practically nonexistent. The area of the county is 1259 square miles and its i)opulation is 11,853 (1920 census). Geology. The geology of the county has been summarized by Laizure^ as follows : "Sedimentary formations extend from the Mendocino County line north along the coast to a point about five miles north of Areata. They cover a strip about 12 miles wide at the south end. "Where the belt crosses the Humboldt Base Line, the forma- tions have a width of 30 miles, gradually running out to a point at the north. In the southern part the rocks consist of massive marine sandstones, with some shale and limestone beds, all of Cretaceous ago. The northern part is composed of clay shales and sandstone of Tertiary age, with small areas of Quaternary sands, gravels and clays, notably along the lower reaches of Eel Ri%-er. The eastern boundary of these sediments runs a little west of north. The contact on the east and covering all the southeastern portion of the county, and extending northwest to Rocky Point above Trinidad there is a belt of Franciscan sandstone, chert, and serpentine, about 12 miles in width. A long, narrow strip of Cretaceous shales, with lenses of sandstone three to four miles wide, borders the Franciscan on the east. It enters the county on the southeast at Humboldt Base Line, trends northwest and passes out at Stone Lagoon, near Orick. "All that portion of the county lying north and east of this belt is composed of Jurassic, Paleozoic, and pre-Cambrian metamorphic and intrusive rocks, including limestones, schists, slates, extensive masses of serpentine, diorite and other crystalline rocks. Most of the gold and copper deposits occur in this area." • Laizure, C. McK., Humboldt Countv : State Mineralogist's Report XXI, p. 29.5, July, 1925. 80 DIVISION OF MINES AND MINING Clay Resources. Common clay suital)l<' for the maiuifricturc of i'e(l-biirnin' is done with wood, for a period of To honrs. The burn is finished Avitli oil, atomized with steam, reqniring 75 hours additional. The finishing- temperature is 1850° F. The machinery is operated by steam ])ower. generated in oil-fired boilers. From five to eight men are employed during the season. The capacity of the plant is 1,000,000 brick or its equivalent per year, and the output is usually about half that amount. The selling price of brick, f.o.b. \ard. is $20 to $22 per thousand. I'lioto Xo. 14 is a view of the plant. Bibl: State Mineralogist's Report XXI, p. 301, 1925; Prel. Kept. No 7. p. 46, 1920. Photo Xo. 14. Plant (^f Thomp.son Brick Co., Eureka, Cal. (Photo by C. McK. Liaizure, State Mineralogist's Kept. XXI, p. 301.) Weatherhy Ranch Deposit. "There is a deposit of clay of unknown extent on property of the Hanify Lumber Company, four miles south of Elk River, under lease to Clarence Weatherhy, Eel River, via Eureka. The strata exposed in a cut on a ridge through the property show clay underlain with two feet of fine volcanic ash. Underneath the ash is six feet of yellow clay, then two feet of lignite coal, with clay again below the coal. Some production of volcanic ash has been made, but the coal and clay liave not been developed. The Hanify Lumber Company's railroad runs within { mile of the deposit."^ ' state Mineralogist's Report XXI, p. 302, 1925. CIjAY resources and CERAl^riC INDI^STRY 83 IMPERIAL COUNTY. ( Hy W. liiiti.iXf; TrcKKK, .Milling; lOiiKincrr.) ' General Features. The priiieii)al industries of Imperial County are agriculture, stock raising' and dairying. its mineral resources are vai'ied and extensive and the rajjid and continued growtli of the towns of Im})erial Valley and the manufacturing industries of tlie Pacific coast have h»d to the (U'velopment of deposits of slnicliiral and industrial materials llii-ough- out the county. Jm{)erial County is bounded on the east by the state of Arizona, noi'th by Riverside County, west by San Diego County and south by ]\Iexico. Its area is 4089 square miles, with a po])ulation of 43,388 (1920 census). The county is served by two railroads, the Southern Pacific and the San Diego and Ai-izona, each of which has several branches to important points. Two main paved highways afford easy access to the county from the north. The highway between San Diego and El Centro forms ])art of the coast route from Tjos Angeles to Imperial Valley, Yuma and Phoenix. The other route from Los Angeles is over the Valley Boulevard by way of Beaumont and Banning to Brawley and El Centro. The Blythe-Glamis route to Yuma and Imperial Valley is one of the main desei-t roads, which enters the county from the north- east at Palo Verde and runs southwest to Glamis, from which point the road follows the railroad north to Niland. Physiography. The most important feature of Imperial County is the broad and nearly level expanse of the Colorado River delta, which separates the Gulf of California from the Salton Basin and is known as Imperial Valley. The Salton Sea region is one of the interesting topogra])hicnl features of the county. Diagonally across the region, from southeast to northwest, it extends as a great trough whose lowest ])oint is nearly 300 feet below sea level. On the west side of this deep trough rise the Peninsular Mountains, whose culminating points are 1 0,000 feet above sea level. On the east side is a desert containing irreguhir ranges and undrained basins ranging in altitude from a few hundred feet to 5000 feet or more. The eastern border of the territory is formed by the Colorado River, whose waters flow through a low valley and Anally spread out over a huge delta as they enter the Gulf of California. The surface of the central portion of the Salton Basin is very even and nearly flat ; about its borders are alluvial slopes. In a number of l)laces rocky masses protrude above the even surface of the basin as rocky islands project out of the sea. Such island-like features are formed by Borego, Superstition and Carrizo mountains, the Cargo ]\Iuchacho iMountains, Pilot Knob and a number of volcanic buttes 100 to 200 feet high south of Salton Sea. The Sand Hills constitute an important feature of the physiography of Salton Basin. The sand hills east of Imperial Valley constitute the largest belt of dunes in this region and also one of the largest in the United States. They extend southeastward from the vicitity of Amos ' state Mineralogist's Report XXII, pp. 248-285, 1926. Such portions of this report were used, with a few sHght alterations, as have a bearing on the clay resources of the county. 84 DIVISION OF MINES AND MINING and ttM-iuinate a few miles beyond tlie ^lexican boundary, beinji,' about 40 miles in len Blake, TV. P., Pacific Railroad Reports, Vol. V. 1853. = Mendenhall, W. C, Ground waters of the Indio Region, Calif., with a sketch of the Colorado Desert: U. S. Geol. Surv.. Water Supply Paper No. 225, 1909. ' Fairbanks, Harold W.. Geologv of San Diego, Orange and San Bernardino Coun- ties: State Mineralogist's Report XI, pp. 76-120, 1892. CLAY RESOURCES AND CEKA:MIC IXUUSTKY 85 Verde mountains. The Palo Verde Mountains are entirely volcanic, beinment were to be installed, at a cost of $18,000. Further details are lacking at the time of going to press. Balicrsfidd Sandstone Brick Compayiy. James Curran, manager. Office and plant at 501 Sonora Street, Bakersfield. The company owns 40 acres of land. Common red brick are manufactured from an alluvial silt which is mined to a depth of ten to twelve feet Avith a clam-shell excavator. The soft-mud process is used. The plant is equipped with a pug-mill and a Martin press. Drying is done on steel trucks, either in the open, or under sheds. As the plant is only operated during the dry season, drying is usually completed in seven days. Firing is done in field kilns, whieli are started with gas and finished with oil, atomized with steam. Thermo-electric pyrometers are used for recording tempera- tures. At the fire-holes, the finishing femj)erature is 2100° F., two feet above the arch it is 1840° F., and two feet below the top it is 1750° F. The eajiacity of the i)lant is 40,000 brick a day, and 14 men are (■iu])l()yed dui'ing the operating season. Bibl : State Mineralogist's Kept. XIV, p. 477; and Prel. Kept. No. 7, p. 48. Kern County Brick Co. Owned by King Lumber Co., Elmer King, l)resident, Bakersfield. This property comprises 12 acres in Sec. 21, T. 29 S., R. 28 E., M. D. M., on the eastern outskirts of Bakersfield. The deposit is a sandy loam 25 feet thick, and has been used for the ])roduction of common brick since about 1900. The soft mud process is used, the equipment consisting of a disintegrator, pug-mill, and 6 mold press. Cable haulage is used to transjiort the brick from the l)resses to the drying sheds. Firing is done in oil-fired field kilns. The capacity of tlie plant is 37,000 brick per day, the annual produc- tion depending upon local demand. Ten men are employed. Titus Chn/ Deposit. H. E. Titus of Kosamond owns two ])lacer claims totaling 40 acres, comjirising the K\W \ of the SE] of See. 11, T. 9 N., R. 1-') W., S. B. M., covering a deposit of pottery clay of good ■ Clay-Workor, May, 1927, p. 486. 90 DIVISION OF MINES AND MINING quality. Tlie (listaiice by road i'l'oiu Ivosaiuond is 4.8 miles in a direc- tion slightly north of due Avest. The clay has been developed by an open pit, and by a 200-foot tunnel, noAv inaccessible. The clay is enclosed in felsite porphyry, and is apparently a local alteration and docoiiii)Osition in ])lace, of a phase of this rock. Inclu- sions of porphyry in various stages of alteration are intermingled with the clay. The deposit has no definite stratification, but appears to lie in a nearly Hal bed, overlain by a red-c<)h)i'ed porphyry capping. Tlie known dimensions of the deposit is 800 feet wide, 700 feet long, and 50 feet dee]i, with unknown possibilities for extension in any of these dimensions. The ])roperty was formerly known as the Hamilton deposit. At various times during a period of over 10 years, clay has been mined from an o]ien pit, and shi])ped to ceramic plants in the Los Angeles district, notably the Los Angeles Pottery Company and the Pacific Sewer Pipe Company both of whicli are now non-existent under their original names or ownership, and more recently to the Tropico plant of Gladding, ^McRean & Co. Tlie clay has been used in stoneware and sewer-pijie mixtures, and a commercial test run has been made for terra cotta mixtures. It is likely that the property will eventually be acquired by one of the manufacturing companies, although at present develojuuent work has not progressed far enough to permit a prediction as to the probable tonnage and quality that can be expected beyond the known limits of present knowledge. Sample Xo. 114 was taken from this dei)osit, and the test results are given on page 312. IT'. ^'. Wehh of Rosamond owns a ])roperty one mile west of the Titus claims, on what is a supposed extension of the same clay bed. This property was not visited. Merry Widow Mine. Mrs. ]Mary Y. Smith of Kosamond is the prin- cipal owner of the ]\Ierrv Widow mine comprising two lode claims in the SWi of Sec. 8, T. 9 5j., R. 12 W., S. B. M., 2.8 miles by road north of Rosamond, of which 1.6 miles is on the highway to ]\Iojave. This is in the Rosamond gold mining district, uoav idle, but at one time a small jiroducer of gold from narrow veins in granite porphyry and slate. Two samples were taken from an 800-foot tunnel on the ]\Ierry Widow property. One of these, No. 115, is footwall gouge from a drift on a vein encountered at a point 200 feet from the portal of the tunnel. The gouge is over five feet in thickness, and lies at an angle of 45 to 50°, dipping south. About 40 feet of this material, measured along the strike of the vein, is exposed in the drift. The test results, page 349. slioAV that the clay has little value for ceramic purposes, on account of jioor plasticity, red color, high shrinkage, fire splitting, and low fusion point. The other sami)l(', Xo. 116, was taken of the decomposed rock that occurs near the portal of the tunnel. It is evidently an altered granite porphyry. Test results, ])age 349, were even less favorable than those obtained on sample Xo. 115. KINGS COUNTY. General Features. Kings County is in the south-central portion of the state, soutli of Fresno County. Its ai'ea is 1559 sfpuire miles, and tlie po])ulation is 22,031 (1920 census). The principal town is Ilanford. The western CLAY RESOURCES AND CERAMIC INDUSTRY 01 edjfe of the county is in the foothills of the Coast Range. The rest of the county is in the basin of the San Joaquin Valley. The mineral resources of tlie county are jiractically undeveloped. Dejiosits of fuller's earth, gypsum, mineral paint, natui'al gas, and ([uit-ksilver have been noted. The commercial production is almost negligible. Clay Resources. Common brick clays are rcasonabl\' abuudaut in llic vicinity of Han- ford and elsewhere in the county. Two former brickyards, the Clinker Brick Company and Trewhitt Brickyard, both near Ilanford, were abandoned prior to 1911. Bibl: State .Alineralouist's Kept. XIV. p. 527, 1913-14; State :\Iin. Bur. Bull. ;J8, p. 24:3 ; Prel. Kept. 7, ]). 49. LAKE COUNTY. General Features. Lake is one of the counties north of San Francisco Bay. It is bounded on the north by ^Meiidoeino aiul (Tlenn counties, on the east by Glenn, Colusa and Yolo, on the south by Napa, and on the west by Sonoma and Mendocino. It has an area of 1328 square miles, and its ])oj)ulation is 5542 (1920 census). The outstanding physiogra])hic feature of tlie county is Clear Lake, which has been a prominent resort area for many years. Clear Lake is surrounded by rolling hills in which are many interesting geological features. The prevailing rocks in the county are the Franciscan (Jurassic) serpentines and slates and Tertiary volcanics. There is a small area of Pliocene, and an area of Quaternary near Clear Lake, besides some undifferentiated Tertiary formations at the southern extremity of Clear Lake.^ ^Mineral ]n-oduction in the i)ast has beeji comjiai'atively small, and has been largely confined to quicksilver and mineral water. Some of the leading minerals found in this section, in part as yet undevelo])ed, are borax, clay, copper, gems, gold, gypsum, mineral water, quicksilver, silver, and sulphur. The entire county is but sparsely settled, and is without rail connec- tions. Besides the production of minerals, the population is engaged in farming, stock raising, and the operation of summer resorts at the numerous mineral springs in tlie county, and on the shores of Clear Lake. Clay Resources. The county was visited by the author in September, 1925, and attempts were made to examine clay occurrences that had been repoi'ted previously by the Bureau,- in which had been mentioned a line of kaolin deposits near the Mount Sam Quicksilver Mine, and undeveloped deposits at Glenbrook, Kelseyville, Soda Bay, and Sul])hur Bank. Tmpiiry was made among local inhabitants, and a number of localities were visited, but no evidence of tiicsc dei)osits could be discovered. As 1 Smith. .T. P.. The geologic formation.s of California: Gal. State Min. Bur. Bull. 72. and geologic map. = Bull. 38, IX 361. Rept. IX, p. 303 ; XIV, 204. Prel. Kept. 7, p. 49. 92 DIVISION OP MINES AND MINING time was not available for prospecting, the search was abandoned. It is obvious that only a deposit of exceptionally high-yrade clay would have commercial value in this region, on account of the cost of trans- portation to market, and while the possibility that such a deposit may be found can not be entirely eliminated, it is unlikely. Common brick clay is not abundant in this region, but there is little likelihood that a brick yard will ever be established on account of lack of market. A few samples of common clays were taken from deposits near Kelseyville, but only one of these, No. 188, was tested. This is a clay shale from an undeveloped exposure 1.4 miles southeast of Kelseyville on the Lower Lake road. The test results are on page 336. General Features. LASSEN COUNTY. Lassen County is in the northeast portion of the state, south of Modoc, which is the northeasternmost county. Its area is 4531 square miles, and the po])ulation is 8507 (1920 census). It is a succession of mountain ranges and high-altitude plateaus, and is only partly devel- oped. Almost the entire area of the county is covered with Tertiary and Quaternary lavas. In the vallej's and around the shores of lakes are Quaternary sediments. Occurrences of cop])er, gems, gypsum, gold, silver, and sulphur are known. There is a small annual produc- tion of gold, silver and miscellaneous stone. Clay Resources. The county was not visited in the course of the ])resent investigation. It is obvious that only clays having exceptional unit value could be commercially produced in the region. A deposit of clay is reported on the Anderson Kanch, at Hayden Hill, owned by H. P. Anderson, but details are lacking. Hayden Hill is a gold mining district. It is pos- sible that kaolinization of some of the rhyolite tuffs, especially those high in alumina, that are known to occur in this district, may have resulted in the development of high-grade clays. In Preliminary Report 7, ]). 49 (1920), the following notes are given: "J. E. Pardee, Susanville. Common brick clay. No recent pro- duction. "A. E. P>uchler, Susanville. Formerly operated a clay deposit, but no recent production." No recent data are available. LOS ANGELES COUNTY.' General Features. Los Angeles County is bounded on the north by Kern County, on the east by San Bernardino County, on the south by Orange County, and on the west by Ventura County and the Pacific Ocean. The ocean shore line extends for about ninety miles. The county comprises 4067 square miles, a large part of which is mountainous. The population, according to the 1920 census, is 936,438. The chief topographic features of the county are the mountain ranges, the valle\s, and the great Los Angeles Plain which stretches 1 Tiu-ker. W. B.. I^os Aiife'elt-s County. Slati- Mineralngi.'^f.s Report XXIII. p. 287. et sen. No data on the ceramic industry are given in thi.s reference, but Mr. Tucker's general description of the county was freely drawn upon. CLAY RESOURCES AND CERAMIC INDUSTRY 93 Iroiii the footliills t employed. Angulo Tile Cotnpanif. riant No. 2; R. F. Anfrulo and Sons, owners. Tliis company lias two plants en^a^cd in the mannfactui-e of hand-made Mission roof and terrace tile. Plant No. 2 is at Reseda, Los Anyeles County, and Plant Xo. 1 is in Santa Barbara (see nnder Santa I^>arbara County). The Reseda i^lant is llie larm'r operation. Clay is obtained from a surface de])osit adjoininji' the plant. A tile maeliine ha.s recently (November, 1927) been added to the ecpiipment. The company has a V. S. i)atent on a s])ecial method of making- hand-made rooting tile. The ])lant is eqnii)ped willi three kilns, fired with gas and oil. Atlas Fire Brick Comimmi. M. I. Power, president; C. J. Walters, vice i)resident ; Stuart Findley, secretary; Clifford Tillotson, manager. Office and plant at P>oyle and Slauson avenues, Los Angeles. This comi)any specializes in the manufacture of silica brick and high- grade fireclay brick. In addition to standard straight fire brick and silica-brick shapes, the company is prepared to make all key and arch shapes, glass-tank l)locks, and special shapes. The raw materials in use include the Emsco white pla.stic fireclay (sample No. 70, p. 272) from Riverside County, German fireclay (sam- ple No. 56, p. 297) and ganister from the coiii])any's deposit near Hicks, San Bernardino County. From 6000 to 12,000 'tons of clay and :5000 to -lOOO tons of ganister are used each year. The mixtures are prepared by dry-pan grinding, followed by pugging. All ela,y brick mixtures are repugged, and then aged in a moist room for a period ai)i)roximating two weeks. The silica brick are all hand molded. Special care must be taken with the large glass-tank blocks, to ensure thorough tamping during molding. Fire brick are made by either the dry i)i-ess or wet process, the latter being by hand molding, followed by repressing. All shapes are air dried, then fired in gas-fired round down-draft kilns. Fire brick are fired to cone 12 (1310° C.) and to cone 14 (1390° C.) ; glass-tank refractories to cone 12; and silica brick up to cone 18 (148o° C). Seven kilns are in operation, and 40 men are employed. Batchelder-Wilson Co. E. A. Batchelder and L. H. Wilson, owners. Office and plant at 2633 Artesian Street, Los Angeles. This company, formerly known as the Batchelder Tile Comjiany, specializes in decor- ative tile for homes, and their arti.stic products have become well-known throughout the region west of the Rocky JMountains. The ])rincipal products are facing and paving tile for interior decorating. Some architectural terra cotta is i)roduced for entrance ways and interiors. The clays used are Hill blue (samjjle No. 9, p. 287), extra select main tunnel (sample No. 18, p. 321) and some pink mottled (sample No. 7, p. 328), supplied by the Alberhill Coal and Clay Company in River- side County ; Lincoln No. 1-6 (sample No. 146, p. 303), from the Lincoln Clay Products Company in Placer County; Bacon red (sample No. 127, p. 335), and Harvey (sami)le No. 133, p. 298), from lone, Amador County, and a small quantity of Santa IMonica clay (represented by sample No. 61, p. 341). Some bentonite from a deposit near Araboy, San Bernardino County, is used in the nnderglazing slip. 7—54979 98 DIVISION OF MINES AND MINING Six standard mixtures are used, jTrading in fired-body color from red to cream. The mixtures are i)rei>ared by jaw erushiiiK, roller-mill .grind- ing, and final png-mill mixinf; and tempering. The batches are seasoned in moist rooms before pressing, a i)eriod of at least two weeks being preferred. All of the jn-oducts are hand moulded in plaster molds, which are made in the plant. The drying is in air, followed by automatic drying ovens. The total drying time is about 48 hours. After drying, an underglaze slip is sprayed on, followed by the color decorations, Avhich are ])ainted by hand. The kiln equipment includes two 7 x 12 foot rectangular kilns, two 20-foot round down-draft kilns, and one 200-foot tunnel kiln, all gas fired. A great variety of colors from the same body and glaze is produced by varying the temperature and atmospheric conditions dur- ing firing. Pyrometers and cones are used on all kilns for controlling temperatures. After firing, some of the tile are buffed on emery wheels to remove a part of the glaze. This is followed by several sprays of raw lin.seed oil, thus producing a pleasing mottled effect. Monorail transportation is used throughout the plant. A small testing laboratory, in charge of a ceramic graduate, is maintained. J. A. Bauer Pottery Co. W. E. Bachman, president, 415 West Avenue Thirty-three, Los Angeles. This is a four-kiln pottery making a complete line of red flower pots, white stoneware, yellow bowls, crocks, vases, and olla.s. Santa ]\Ionica clay (sam])le Xo. 61, p. 341) is used for flower pots and ollas, while Alberhill and Lincoln clays are used for the light-colored, vitrified stoneware bodies. Approximately 4000 tons of clay are consumed per year. The clays are spray-washed to remove surface contamination, then pugged. Flower pots and some of the other ware are machine molded. For other products turning (' jiggering') or hand moulding are used. All of the smaller ware is dried in 24 hours, natural gas auxiliary heating being used in the drying room. White, yellow or cream glazes, where used, are applied by dipping before firing. A single firing matures both the body and the glaze. The four kilns are of the round down-draft type, fired with gas, but equipped to burn oil if necessary or desirable. The red ware is burned to a temperature of 1850° F. in three to four days, and the cream body ware is fired to 2250° F. in about the same time. One of the kilns is ordinarily operating on the light colored body, and is equipped witli pyrometric control. At present this is the only plant in Los Angeles manufacturing floAver pots. Not over half of the company's business is in flower pots, but this constitutes the largest single item. In order to permit the full time operation of the plant on a systematized plan, a stock of ware aggregating over $100,000 in value is constantly kept on hand. Fifty men are employed. Bibl : Cal. State Min. Bur. Prel. Kept. Xo. 7, p. 50. California Brick and Tile Company.^ (Formerly the Owens Brick Data supplied by W. B. Tucker, district mining engineer, December, 1927. CLAY RESOURCES AND CERAMIC TKDTTSTRY 99 Company.) K. A. Miller. ])resi(l(iit ; 11. W. Urou^hton, secretary. Office and i)iant at (}1.')9 Kcstcr Street, Van Nuys. The company owns *J(t aeres of land, and mannl'actni'es cojnnion bi-ick only. TIk' de[)osit consists of red and yellow clay, 20 to .']() feet tliick, nnderlyinji: an overhnrden of soil Jroni one to two I'eet tliick. The clay is excavated from an open pit by a uilding, 321 West Third Street, Los Angeles. The plant is in South Gate. This factory manufactures an extensive line of glazed wall tile and ceramic floor tile. English china and ball clays are used in the white-burning bodies, but Lincoln clay (sample Xo. 146, p. 303) from Placer County and Cardiff fire clay (sample No. 36, p. 311) from the company's property in San Diego county are used in the cream, buff and darker- colored bodies. The finer cla\s to be used in the manufacture of white bodies and other high grade ware, are ])repared by blunging and filter pressing the ground material. Plastic clay mixtures are prepared in ])ug mills, and ai'e well seasoned before use. Dry-pressed floor and wall tile are made in hand-operated ])resses. PMoor and wall tile with an undulating surface are produced by hand l)ressing of pugged clay in ])laster molds. The latter are highly prized by architects to secure certain artistic effects, as the undulating sur- face gives the impression of wear resulting from long use. Drying is done Avith hot air, in-oduced by waste heat. The drying time varies from 24 to 36 hours depending upon the size of tile. ^lonochrome glazes are api)lied by hand dipping in the glaze slip. Polychrome work is done with a glaze bulb. Some brush work is done in special cases. All of the glazed tile are given a double firing. There are three biscuit kilns with a firing cycle of 72 to 90 hours to attain a maximum temperature of 2400" F. Three glost kilns are in use, with a firing cycle of 36 hours to 1800" F. The apparent discrepancy in the capacities of the biscuit and glost kilns is explained by noting that the tile are packed in sand in the biscuit kiln saggers, but must be supported on 100 DIVISION OF MINES AND MiNI^fG pins in the glost sagjj:ers, hence requiring- more space per nnit of tile area in the latter case. ]\Inch of the work in the factory, sucli as api)lyin«? glazes, removing loose dust from tile after dry pressing, packing and unpacking of saggers, etc., is of such a nature that Avomen employees are used, men being employed only for the heavier duties, such as operating the presses, trucking, kiln setting or drawing, and firing. City B)'ick Co. The plant is at 1900 West Manchester Avenue, (Eighty-sixth Street) and Western Street. This company makes common red brick only. The clay in use is a surface deposit of loose sandy loam, with just sufficient bonding ])ower to ^lermit the manu- facture of a satisfactory building brick by the soft-mud process. The clay is mined in a shallow pit by horse scrapers, wliich deliver the material to an incline tram whicli dumps into a hopper feeding a disintegrator and pug mill, followed by a 6-brick press. The brick are carried to the drying sheds by rope conveyors. The dried brick are fired in gas-fired open kilns. Handling losses are apparently higher than in most i^lants, on account of the low strength of the brick in the plastic and dry state. Claycraft Potteries, Inc. Gus Larsen, president; F. H. Koberts, vice president; W. C. Reordan, treasurer; Henry Prussiing, secretary. Office and plant at 3101 South Fernando Road, Los Angeles. This company manufactures faience art tile, using an Alberhill clay body that matures at cone 5 (1180° C.) and applving glazes that mature at cone 4 (1050° C). The plant is equipped with two 8-ft. wet pans, two tile augers, a sagger press and three tile presses, one of which is power-driven and has a capacity of 900 tile per hour. All fancy i)ieces are hand-molded in plaster molds. The ware is dried in three 6-ft. by 7-ft. by 25-ft. tunnel driers. The biscuit firing is done in three '220-ft. round down-draft kilns, gas fired. Three muffle kilns are used for the giost firing. Twenty-five men are employed. H. F. Coors Co., Inc., H. F. Coors, manager. P. 0. Box 517, Ingle- wood. This plant is at 419 South Judah Street, Inglewood. It was established in December, 1925, for the manufacture of porcelain plumb- ing accessories and electrical specialties. English china clay and Coors ball clay (sample No. 57, p. 264), Campo or Kingman feldspar, and various grades of silica are used in the ])()dy mixture, which is prepared by ball-mill grinding. Some of the ware is dry -pressed, and some is cast. A hot-air drier is used. An 8-foot gas-fired round down-draft kiln is used for both the biscuit and the glost firing. A small muffle kiln is used for decorat- ing, which consists principally of labeling faucet handles. Davidson Brick Co. Nathan Davidson, owner, 5301 Chicago Avenue, Los Angeles. This is a well-equipped and Avell-arranged plant for manufacturing (Common red brick. The clay varies from an adobe to a soft clay shale. Mining operations have exposed a bank 60 to 70 feet high, and 300 feet long. The pit extends into a gentlj^-sloping hill- side above the plant. An electric shovel is used for mining and loading into dump cars, which are hauled to the i)lant by a gasoline locomotive. CLAY RESOURCES AND CERAMIC INDUSTRY 101 Brick are made by the stiff-mud, side-cut process. A rope conveyor is used to deliver the brick to the drying sheds. Oil fired field kilns are used. A sam])le (No. 60) of the more shaly variety of clay was taken as i-epresentative of the class of material to be expected in this district. The tests (p. o-tO) indicate that the drying and firing jjroperties of the clay are not greatly different from those of the Santa Monica clay (sample No. 61, p. 841), which is widely used in Los Angeles County as an ingredient of sewer pipe, conduit, flower pot, and olla mixtures. Empire China Compunj). Office and plant at Burbank. ]\Ir. ]\Ior- gan, superintendent. This is a well-equipped plant, containing seven round down-draft kilns that operated for a number of years for the manufacture of semi-porcelain hotel and dinner china. Experiments have been in ])rogress for a number of monllis on tlie manufacture of vitreous dinnerware, and the management expects to start production of this ware during the si)ring of 1928, using a California feldspar and silica, Nevada china clay, and a certain amount of Florida clay.^ I'J)nsro Rrfractorics Conipanij. E. M. Smith, president. Office and plant in Southgate, at Manchester Avenue and Atlantic Boulevard. This company was established in 1927, and was not visited by the author, such data as are included here having been supplied by the com{)any. The company manufactures fire brick, silica brick and glass- tank refractories. The clays are obtained from El Toro, Orange County. (Hunter Ranch ?, see samples No. 63, 64 and 268, p. 260), and from the Emsco pit in the Alberhill district, Riverside County. Eight gas-fired kilns are in use. Gladding, McBean and Companij. Southern Division. Atholl ^McBean, ])resident; Fred B. Ortman, vice president. Los Angeles office at 621 South Hope Street. In 1926 this com])any merged with the Los Angeles Pressed Brick Company. The Southern Division of the com])any includes the following ])lants : the Alberhill (see under River- side County), Santa ]\Ionica and Los Angeles plants, all formerly owned by the Los Angeles Pressed Brick Company ; and the Tropico plant. The company also owns the Goat Ranch clay deposit in Orange County (see under Orange County). Los Angeles Plant. 952 Date Street, Los Angeles. This is the largest of the plants formerly owned by the Los Angeles Pressed Brick Com])any, and has perhaps the greatest manufacturing resources of the southern California plants of Gladding, McBean and Company. The ])roducts made at this plant are terra cotta, face brick, 'quarry' tile, and roofing tile. The plant is in the heart of the Los Angeles com- mercial district and all clay must be shipped in. The terra cotta mixtures are the same as tho.se in use at the Tropico plant, described below, and are prepared in the same manner by dry pans and pug-mills, followed by a variable period of seasoning in waste- heat humidifiers. The face brick mixtures consist of varying proportions of Santa IMonica red-burning clay and a number of varieties of Alberhill clay. The face brick production of this plant is the second largest in the * G. Ray Boggs, private communication, December S, 19".7. 102 DIVISION OF MINES AND MINING Gladding, McBean organization. A wide range of colors and textures are ])rodnced. Quarry tile are Jiaiul made from mixes similar to those used for face brick, and are produced in a wide range of red colors. The product is knoAvn as 'Palacio' tile. Practically all of the roofing tile produced by the Southern division and approxinuitely 60% of that manufactured by all of tlie comi)any's l)lants is made at the Los Angeles plant. Both machine and hand made tile are produced. The laboratory is constantly experimenting on new glazes and body mixes, and many distinctive effects have been produced. The jilant is well equipped. Practically all labor is ])erformed mechanically and all moving of material is done by motor. There are 25 kilns, divided as follows : thirteen round down-draft kilns, four terra cotta muffle kilns, and eight rectangular mufflle kilns for enamel work.. Santa ^Monica Plant: Colorado Avenue and Twenty-fifth Street, Santa Monica. Formerly owned by the Los Angeles Pressed P)riek Company. The products are roofing tile, hollow tile, flue lining, chim- ney pipe, quarry tile, and brick. Most of the clay used is mined at the plant, which also supplies a large quantity of clay for the Los Angeles ])lant. The ])roi)erty includes 45 acres of clay land. The deposit is similar to that in use by other manufacturers in this area, including the Western Brick Co., the Simons Brick Co., and the Santa Monica Brick Co. On the Gladding, McBean jiroperty the clay is from 10 to 36 feet thick, dii)ping north- westward, and increasing in depth in that direction, presunuibly under- lain by gravel. Sample No. 61 was taken from the stock ])ile in the ])lant, and is an index of the type of material mined by this company and others in the district. The test results are on page 341. All products are made by the stiff-mud process, on auger machines. The quarry tile, known as 'Promenade' tile, is made in a wide variety of red tones, with here and there a purplish to greenish hue. Twelve round down-draft kilns are operated. Bibl: Bull. 88, ]). 214 (L. A. P. B. Co.), and p. 217 (Western Art Tile Works (now the Tropico plant). Prel. Rejit. 7, i)p. 53-56 (Los Angeles Pressed Brick Co.), and pp. 56-57 (Pacific Minerals and Chemical Co., now the Tropico plant). Tropico Plant : Located in Glendale. This plant was started in 1902 as the Pacific Art Tile Company, the first factory of its kind west of the Rocky Mountains. After several reorganizations, the plant was eventually ac(|uired by Gladding, McBean & Com])any and in 1922 the name was changed to its present form. The ]irincipal products of the plant are sewer pipe, flue lining, architectural terra cotta, and faience tile. Sewer Pipe: Tlie sewer pipe mixture contains red-burning common clay from Santa Monica (sam])le No. 61, p. 341), Emsco red (sample No. 72, p. 328), and one or more other clays from various sources. The clay is prejmred by dry pan and inig-mill, shaped in power-driven ('steam) ])resses, dried on slatted floors, and fired in down-draft bee- hive kilns, fired with gas up to 1100-1300° P., and finished to cone 03, 1980^ F., with oil. The smaller pipe is set two lengths high, and requires a firing schedule of 88 to 100 hours.' The larger pipe is set three high, CLAY RESOURCES AND CERAMIC INDUSTRY 103 and r('(|uiiv.s a 12()-lionr firiii": schedule. The total kiln turnover is 10 to 11 days. Thirty-two kilns are in u.se for sewer pipe and flue lining, each with a capacity of approximately 40 tons. Flue Lininrindinsr followed by a puij-mill. After sufficient seasouinp-, the pieces are shaped by hand pressing in plaster molds and air dried before firing. A gas-fired round down-draft kiln is used for firing, the heating schedule ranging from 68 to 72 hours. ]\Iany of the models are imported from Spain and Italy. The market for the products is not confined to the Los Angeles district, as the artistic value of the ware has often imi)ressed visitors from other sections of the United States, and many pieces have been shipped to the eastern and middle western states. Bibl: Cal. State Miu. Bur. Prel. Kept. Xo. 7. ]). 51. K. & 31. Pottery. M. C. Myers, president. Oi^ice and plant at 2318 East Fifty-second Street, Los Angeles.. This pottery makes stoneware from Alberhill clays, using the E-101, and the hill blue (sample X^o. 11, p. 257, and 9, p. 2S7) varieties. Ollas are also made from the pink-mottled clav from Alberhill (sample No. 7. p. 328). The stoneware is made by turning and the glaze is applied to the dried ware before firing. The plant is equipped with three round down-draft gas-fired kilns, 25 feet, 22 feet, and 15 feet in diameter, res]iectively. The annual wholesale value of the product is nearly $60,000. Bibl : Cal State Min. Bur. Prel. Kept. Xo. 7, p. 51. K and K Brick Company.^ 0. J. Cubach, president; II. D. Simons, secretary. Office. 801 ^Merchants X'ational Bank Building. Los Angeles. This company owns a 38-acre property in Bishop Canyon, Los Angeles, and manufactures common brick. The deposit consists of blue and gray plastic shale, 10 to 20 feet thick, underlying from two to five feet of adobe soil and gravel. The clay is mined by hand methods in an open cut, and is transported to the plant in small cars. The stiff-mud process is used. The plant is equipped with a dry pan, screens, pug-mill, and a Kaymond auger machine, with a wire cutter. The brick are dried in open drying sheds, and are fired in six open field kilns. Both natural gas and oil are used as fuel. The plant o]>erates throughout the year and 35 men are employed. Power is suii]ilied by a 250-h.p. boiler. The rated capacity of the plant is 75,000 brick per day. Bibl : State Min. Bur. Prel. Kept. 7, p. 51. La Cal Tile Company. Val Alden and Kittridge streets. Van X'uys. A recent report- states that this company was building a plant on the above site, at a cost of $70,000. Further details are lacking at this writing. Lindennan tf- Decker Company.'^ Address, Lomita. This is a firm ^ Data .supplied by W. B. Tucker, district mining engineer, November, 1927. = Clay-W' orker, March, 1926, p. 207. CLAY RESOURCES AND CERAMIC INDUSTRY 105 of general eontractoris who o\vii a lO-aere proi)erty at Harbor City that is now under lease to Mexicans, who are manufacturing hand-made i-oofing tile. The deposit consists of 10 to 15 foot of rod clay, overlain by one to to two feet of gravel. Hand methods of mining are used, and the clay is delivered to the tile plant bj^ a horso-drawn dump-cart. The clay is l)repared and the tile shaped by hand. Drying is done in tlie open aii-. A round gas-fired kiln is used for firing. Long Beach Brick Companji.^ H. A. Ilavnor, president; H. C. Arm- strong, secretary. Office at 154 Elm Street, Long Beach. The co)npany owns a 10-acre property at Harbor City, and manufactures common brick. The deposit consists of rod clay, 10 to 20 feet thick, covered by a maximum of two feet of gravel. The clay is mined b.y scrapers, and is transported to the plant by belt conveyors and Ford trucks. The equipment includes a dry pan, elevators, screens, American anger machine, and wire cutter. Drying is done in o]ion-air drying sheds. Rope conveyors are used to transport the brick to and from the drying ,vard. Six oi)en field kilns, firod with natural gas, are used. The ])lant usually operated during ton months of the year, employing 25 men. Electric power is used, the installed cai)acity being 200 h.p. The rated capacity of the plant is 45,000 brick per 8-hr. day. Bibl : Cal. State :\[in. Bur. Prcl. Kept. 7, p. 51. Los Angeles Brick Co. A. A. Conger, president; E. W. ]\Iurphy, vice president ; Henry Prussing, secretary ; Gustav Larsen, director in charge of operations; W. C. Roordan, director in charge of sales. Home office, 1078 ^Mission Road, Los Angeles. This company owns and operates three common-brick and hollow- tile yards in the Los Angeles district, and has recently built a plant at Alberhill to manufacture tile, fire brick, and other ])roducts (see under Riverside County, p. 174) from clays mined on their own pro]i- erties, acquired through the purchase of the holding.s of the California Clay IManufacturing Company. The Los Angeles brick yards are the ^lission Road ]ilant, at the corner of ^Mission and jMarengo streets, near the County Hospital; the Chavez Canon plant, in Chavez Cafion, west of Adobe street; and the Seventh Street plant, at East Seventh Street, on the corner of Utah Street. ^IrssTOX Road Yard: This property comprises 15 acres. The clay is a surface material from 25 to 30 feet thick, underlain by five or six feet of sand. Common brick only are made at this plant, using the soft-mud, sand-mold process. The brick are air-dried, then fired in ojien field kilns, using gas as fuel. The average daily capacity of the yard is 80,000 brick. A Hoffman continuous kiln, fired with coal screenings was formerly in use, but has been dismantled. Rope conveyors are used to deliver tlie brick pallets from the ]U'esses to the drying yard. Chavez Caxon Yard: This is a 26-acre property. The clay is a thin-bedded Puente (Lower Miocene) shale, forming a bank over 100 'Data supplied by W. B, Tucker, district mining engineer, November, 1927. 106 DIVISION OP MINES AND MINING 'J 0/ r5 a o O o O O o o W CM CLAY RESOURCES AND CERAMIC INDUSTRY 107 feet lii^li, and dipping: southward into the hill. Tiie individual beds of shale vary from a very fine-.trrained plastic clay, to a sand, the different phases being ])resent in such jn-oportions as to make an excellent material for brick and hollow tile. The clay is mined by a team and scra])er, dumped into a hoi)per, delivered to a ear, which is hauled up into the ])lant by an electric hoist. The clay is ground in a dry pan, and fed by belt conveyors to ])Ug-mills and auucr machines. The bricks are dried in driers heated with steam from auxiliary boilers. Firing is done in open field kilns, with gas fuel. The capacity of the plant is 80,0()() brick and 100 tons of hollow building tile per day. Seventh Street Yard: This yard is 12 acres in area. The clay belongs to the upper ])ortion of the Boyles Heights Terrace formation. The soft-mud ])roeess was used, followed by air drying, and firing in open field kilns. It is i)robable that this i)roperty Avill be sold, as it has become too valuable for industrial i)roi)erty to Avarrant its continuance as a brick yard. IJibl: Cal. State Min. Bur. Prel. Kept. No. 7, p. 52. Malihu P(jfttries. Owned and operated by the ]\Iarblehead Land Co. ; R. B. Keeler, plant manager, P. O. Box, 518, Santa Monica. The plant is on the Coast highway, north of Santa Monica. The products of the plant are plain and decorated wall tile, made from a terra cotta body. A vieAV of the plant is given on ])hoto No. 16. A variety of clays are used, including a number of clays from the ]\Ialibu Ranch, some Alberhill clays, and Engli.sh ball clay. The mixes are prepared by grinding in a 4-ft. dry pan, elevating to a bin, screen- ing, and ]iug-milling. followed by six weeks ageing. ]Most of the tile are shai)ed in a ^fuller tile auger, but some are liand-i)ressed in plaster molds. Saggers and tile setters are made at the plant, by hand. A Carrier drier, oi>erating on an 18-hour cycle, is used for drying the tile. The saggers and setters are dried in the open. Three up-draft kilns are in use. On biscuit firing, 10,000 sq. ft. of tile can be loaded per kiln, and the entire firing cycle takes one week. The finishing tem])erature is 2300'' F., which is reached in 96 hours fi-om the start of firing. On glost firing, each kiln holds 5000 sq. ft. of tile, the finishing temperature is 1600° F., the firing occupies 48 hours, and the entire cycle takes four days. Normally, one kiln is on biscuit firing, one is on glost firing, and the third is used for either, according to conditions. The kilns are fired with oil, atomized by air. Mission Brick Companij.^ ]Mrs. A. E. L. Anderson, 755^ Santa ]\Ionica Boulevard, Los Angeles, owner. Joseph F. Reutera, manager. Office and plant at 6140 Scpulveda Boulevard, Van Nuys. The product of the plant is common red brick. The i)roperty consists of five acres of land, containing a bed of red clay from 5 to 20 feet thick, overlain b\- from one to two feet of soil. Mining is done in an open pit, using scrapers which are hauled by a Fordson tractor to a hopper which feeds a belt conveyor delivering to a bin at the plant. The soft-mud process is used. The plant is equipped Avith a pug-mill and a Quaker brick ]:>ress, Avhich has a capacity of 20,000 brick ])er day. The brick are dried under sheds, to which they are transported in hand trucks. ' Data supplied by W. B. Tucker, district mining engineer, December, 1927. 108 DIVISION OP MINES AND MINING o O m CD I— t 0) C CO o o 1-1 So So ^^ Cm o- a u o o be .s o z o o a CLAf RESOURCES AND CERAlSflC INDUSTRY 109 Two ji:a.s-fired field kilns arc used. liavin<;' a eai)ac-ily of 50,()()() bricks each. Electric power is used in llic j>lant, the installed capacity being 60 h.p. Twenty men are employed (luring llic operatinjr season, whicli is usually four months. Mission China Conijxinn. Victor Ki'enior, i)residcnt ; Jas. Tiffany, manager. General offices at .3121 W. Third Street, Los Angeles. Plant at 652 S. Griffin Avenue. Tiiis ])lant has been manufacturing semi- jiorcelain hotel and dinner ware for a number of years. The raw materials in use are P]uglisli china and ball clay, Edgar (Florida) kaolin, and California feldspar and silica. The body mix is prepared by screening through 150-mesh, blunging, filter-pressing, and pugging. ]Most of the ware is shaped by jiggering, but casting is used on the more complicated shapes. Steam drivers are used, operating on a 12-hour cycle. Saggers arc molded by hand at the plant. The biscuit ware is fired in two 17-ft. 6-in. up-draft kilns, to a finish- ing temperature of cone S (1225° C), requiring 55 to 60 hours. The ware is then dipped in glaze, and fired in two 16-ft. glost kilns to cone 5 (1180° C), in 30 to 35 hours. Two days are required for cooling both tyi^es of kilns. The paper transfer process of decorating is used, and the decoration is fired on at cone 016 (735° C). Two decorating kilns are in use, which are fired in 12 to 14 hours, the entire cycle requiring 30 hours. All kilns are fired with natural gas. Fifty men and women are employed in the plant. IMost of the work is i)aid by piece rates, which are the same as those established in eastern potteries. Pacific Clinj Ptuducts Co.^ William I^acy, president; Robert Linton, vice president and general manager; W. R. Faw^eett, secretary- treasurer; Wm. McClintock, general superintendent. Main office, 1151 South Broadway, Los Angeles. This company owns and operates three factories in Los Angeles district and several clay proi)crties in River- side and San Diego counties. The present company supersedes the Pacific Seiver Pipe Company whicli was formed some years ago by consolidating several smaller companies situated in Los Angeles, Corona, and Elsinore, these smaller companies having started business around 1880 to 1885. Clay Properties : The company owns and operates the following clay mines : Name Shipping point Douglas.s Alberhill, Riverside County McKnight Corona, Riverside County Wildomar Wildomar, Riverside County 'Hoist Pit KIsinore, Riverside County Kelly No. 1 Farr, San Diego County ' The company owns a one-half interest in this property. In addition the company operates under lease several properties in Orange and San Diego counties ; also owns and holds in reserve for future operations five additional tracts in Riverside and San Diego counties. The total clay lands owned outright total 625 acres. The bulk of the clays used in the company's plants come from its own mines, although some are purchased from the Alberhill Coal and Clay ' Description prepared by the company. 110 DIVISION OP MINES AND MINING ft o 3 O o >. o o be O o O CO ■o O O o £ o ft .5? 'S w o o H O W CLAY RESOURCES AXD CERAMIC INDUSTRY 1 1 1 Comp.iny, the Enisco Chiy ('oiiii);my, and llie Lincoln Clay Products Company. Many difforont clays cntci- into tlic manufacture of the various products nuide, wliicli include s(>\ver pipe, electrical conduit, face brick, enameled brick and tile, fire brick and refractory shapes, firechiy. flue lininji' and ^as flues, drain tile, stoneware, earthenware water coolers and other articles. Plants: Three factories are operated at ])resent, viz, the Lincoln TIeifrhts plant. Avenue TAventy-six and ILunboldt Avenue, Los Ang-eles; the Slauson plant. Slauson and McKinley avenues, Los Anii'eles, and the Los Xietos plant on the eastern edg'e of the Santa Fe Sprinfi's oil field. The plants have a combined cai)acity of over 90,000 tons of clay ]n'oducts per year. A ])lant at Terra Cotta, near Elsinore, and two l)lants at Corona Avere also formerly 0])erated. GeiU'ral views of the Lincoln Heights and the Los Nietos i)lants are shown on photos No. 18 and 19. Lincoln Heights Plant .- J. L. Davies, sui)erintendent. This factory was built about 1890 and was equi]>ped to manufacture sewer pipe, brick and stoneware. At ]iresent it com])rises a brick department in-oducinji' face brick, enamel brick and tile, fire brick and refractory shapes and roofin<]: tile ; and a stoneware department making' a com- ])i-ehensive line of grey earthenware, ollas, mixing bowls, etc. Clays for the stoneware are selected with esjiecial reference to producing a body as dense and impervious as possible; for ollas, or self-cooling water jars, the body should be slightly porous, since the cooling comes from evaporation of water which percolates through the jar to the outer surface. The mixes are finely ground in a Raymond hammer i)ulverizer, the dust being lifted by a suction fan a height of 10 feet to the pug-mill feeder. The pugged clay is allowed to soak in the 'sweating room' for 24 hours or more, then goes to the jig rooms where there are 9 potters' wheels suitable for making all kinds of turned ])ottery up to a 12-gallon jar. The ware is dried in steam- heated dryers, then dipped in the proper glaze. Some of the stone- ware is given a biscuit firing before glazing, but most of it is made at a single bui'ning. using a slip glaze wliich niatures at the same tem])era- ture as the body. The stoneware bodies mature at about cone 8, and are a cream or light yellow color. Saggers made at the plant are used for some of the ware, chiefly for sup])ort. but as much ware as possible^ is open fired. There are o kilns 20 to 24 feet diameter used for stoneware. The brick department equipment consists of 3 dry pans. Hummer screens, 2 pug-mills, 2 auger machines, tAvo 14-brick American cutters, 2 rejiresses, 2 humidity di-yers holding 40,000 brick each, an ovei'head traveling crane Avith clam shell for clay unloading, 2 electric lift trucks Avith i)allets for handling brick, and 11 kilns 80 feet diameter. The cai)acity is 40.000 brick per day. A AucAv of the clay bins and unloading crane is shoAvn on photo No. 20, and a pug-mill, auger machine and cutter is shown on photo No. 21. The stiff-mud brick — comprising the rough and smooth texture wire cut face brick and re-pressed Avire cut fire brick — are dried in the humidity dryers in 42 hours. About 6 days are required for the firing, the finishing temperature being about 2100^. Dry press brick go directly to the kilns Avithout preliminarA^ drying, and are burned to 112 DIVISION OF MINES AND MINING n >, m 3 o o >, o o c <; CO o o O o 3 ■a p >. d O o '3 c (0 o O 0) 0) p. o z; o o 0^ CLAY RESOURCES AND CERAMIC INDUSTRY 113 about 2050^. Enaincl brick are made on biscuit, or bui'iied ])ressed brick, whicli are coated with enamel slips and buiMied a second time to mature the glaze. A variety of very attractive shades of red, tan, g'rey and other colors is made in the wire-cut brick. Present architectural practice favors eombininji- ditferent shades and colors, following the impressionistic idea, and tliese combinations are ])roved very effective in lending distinction to face-brick buildings. The Pacific enamel brick is in wide deiiiaiid and is ship|)ed to all tlie Pacific Coast states as well as abroad. A comph'te line of fire bi'ick and i-clVactorics is also inanufactui'ed. Three grades of standard fire-brick are made, with softening points of Photo No. 20. Clay bins and unloading crane, Lincoln Heights plant, Pacific Clay Products Co., Los Angeles. (Photo by courtesy of the company.) about 3200° F., 3100° P. and 3000° F., respectively. The highest grade brick is hand molded, the others made on the auger machine and repressed. They are burned to about 2500" F. Roofing tile are also made, using a combination Hummer machine. They are dried on waste heat drying floors and burned in the brick kilns. Over 20 different clays are used at this jilant, coming from Riverside, Orange, San Diego, Los Angeles, and Placer counties. The plant site comprises over six acres, and lies between main lines of the Santa Fe and Union Pacific railroads, having sidings from each. The plant is 8 — 54979 114 DIVISION OP MINES AND MINING equipped to use either natural gas or fuel oil. Machinery is all motor- driven. About 130 men are employed. The company's laboratories are located at tliis plant and are fully equipped for chemical and testing- work. A high temperature testing kiln capable of heating up to 3400'' F., is used for testing fire brick. Routine testing for color and shrinkage is regularly carried on. All kilns are equipped with pyrometers which are used for control in connection with Orton standard cones. Los NiETOS Plant : Cecil V. McClintock, superintendent. The Los Nietos factory is the largest and newest of the plants, and is situated I'HOTO No. 21. Pug-mill, auger machine and cutter, Lincoln Heights plant, Pacifle Clay Products Co., Los Angeles. (Photo by courtesy of the company.) on a 46-acre tract on the edge of the Santa Fe Springs oil field. It is a thoroughly modern, well-arranged plant. Sewer pipe is the principal product, but electric conduit segmental sewer blocks and lining blocks, drain tile and flue lining are also made. The plant makes sewer pipe, electric conduit, roofing tile, drain tile, flue lining and gas flues. Clays are shipped in from Riverside and San Diego counties and some clay mined on the premises is also used. The equipment comprises three 9-ft. American dry pans, 2 pulver- izers, gravity screens, four 8-ft. American wet pans, one 14-ft. pug-mill. CLAY RESOURCES AND CERAMIC INDUSTRY 115 3 sewer-pipe presses, 1 aiip-er machine, and .'}() riituhu- down-draft kilns 30 and 34 feet dianietei-. Some of the dry and wet pans are sliown on ])hoto No. '22, and one of llie s(>wei'-pipe presses is sliown on i)hoto No. 23. The dryinji' Hoor is 220 x !t20 ft. and is shown on photo No. 17. There is a \vell-equi|)i)('d machine shoj) and testing ])laii1 foi- sewer i)ipe. Steam is fni'nislied from two 250-h.p. IJaheock and Wik'ox boilers, with three 150-h.p. luhuhir hoik^rs as stand-by. Excepting tlie steam-driven sewer-pipe presses all e(inipment is driven by electric motors. Natural gas and oil are both used for fuel. Clays are shipped in from Riverside and San Diego counties and used in connection with red shale mined on the i)remiscs. The clay track is elevated above the storage bins so that the clays are dumped Photo No. 22. Dry pans and twin wet pans, T^os Nietos plant, Pacific Clay Products Co., I^os Angeles Couiily. (Photo by courtesy of the company.) directly from the ears at minimum cost. Some of them require fine grinding which is done by regrinding the oversize from the screens in pulverizers of the squirrel-cage type. The drying room is equipped with steam-heating pipes overhead and underneath the floor, affording very satisfactory control. From 2 to 15 days is required to dry the ware, depending upon the size. Firing time varies likewise from 3 to 8 days. The bodies mature at 2100° F. to 2200° F. The salt glazing is done during the last two hours of the firing, i. e., when the kiln is at maximum heat, by throwing a shovelful of salt into each fire-box every fifteen minutes. The salt volatilizes, is carried through and around the hot pipe, and as the vapor comes in 116 DIVISION OP MINES AND MINING contact with the clay the alkali in the salt combines with the silica of Ihe clay to form the ^laze on the surface. All sizes of sewer pipe up to aiul including 80-inch are made. Seg- mental blocks for making sewers of larger size are also among the products. The plant emi)loys 150 men. The i)lant is served by both Santa Fe and Southern Pacific railroads, having sidings connecting directly with each. Slauson Avenue Plant : Roy Lacy, superintendent. The Slauson Avenue plant was built about 1885. It is located on a tract of six acres on McKinley Avenue from Slauson Avenue to Fifty-third Street. It is served by the Santa Fe Railroad, the plant sidings connecting Photo No. 23. Sewer-pipe press, Los Nietos plant, Pacific Clay Products Co., Los Angeles County. (Photo by courtesy of the company.) with the tracks on Slauson Avenue. Equipment consists of a conveyor unloader for clay, 2 dry pans, pug-mill, double-shaft auger machine, and sewer-pipe press. There are seven 30-foot kilns and one 28-foot. Pomona Brick Company.'' E. G. Stahlman, president; H. F. Stahl- man, secretary. Address, Pomona. This company owns a 10-acre property on West Ninth Street, Pomona, and manufactures common brick. The dei)osit consists of red sandy clay, 8 to 20 feet thick, without over- burden. The clay is loaded by a small steam shovel into trucks. The plant equipment includes a dry ])an, screens, pug-mills, and a ' Data supplied by W. B. Tucker, district mining engineer, November, 1927. CLAY RESOURCES AND CERAMIC INDUSTRY 117 Potts brick pi'ess. Tlie brick are conveyed to a (lryiii«i' yard on rope conveyors. Five field kilns, fired with natural ^as, are in use. The plant operates during about six months of the year, and employs 14 men during that jieriod. About IK^ h.p. of steam ))ower are required. The rated capacity of the jilant is ;W,0()() brick i)er 8-hi-. day. Bibl: Cal. State Min. Bur. Prel. Kept. 7. j). 58. Puinona Tile Manufacturini, Tliird and Reservoir streets, Pomona. R. J. Scliroeder, j^residt-nt and treasurer; C. V. Svendsen, superintendent. This company manufactures ceramic floor and wall tile, using Edgar clay from Florida, English china clay, California and Arizona feldspar, California silica, and some Santa ^Monica clay where red-burning bodies are re(iuired. Albci-hiii and Lincoln clays are used for saggers. The tile are shaped in hand-operated dry presses. At the time of visit. July, 1925, two down-draft kilns were in opei'ation, and a third kiln for increasing the capacity by HO'^f was under construction. Gas is used for fuel, with oil in reserve. The kilns are fired to cone 11. The plant emj^loys from 40 to 45 employees, mostly women and girls, Avho do the Avork of packing and un])ackinu- the saggers, cleaning the tile after firing, and pasting them on paper. Poxon Pottery. G. J. Poxon, president ; Earl Lincoln, foreman. Offices 2300 East Fifty-second Street, Los Angeles. This pottery makes a complete line of plain and decorated table ware. All of the clays used are imported from England. The im])orts amount to about 1000 tons per year of ball and china clay. Feldspar and silica of the best quality are obtained from various sources in southern California, mainly from Riverside County. After coarse-crushing to about Y' size, the silica and feldspar are mixed in the proper ]n'0]iortion with the clays, and the grinding is finished in a wet ])uli). The mix is tlien passed to filter presses for the removal of excess moisture, and the filter cake is then ready for shaping. Power-driven wheels are used tliroughout for all shapes that can be made mechanically. After shaping, the ware is dried for about three hours in gas-heated drying rooms, or for a longer time in the factory atmosphere. The biscuit firing is done in gas-fired kilns at a temperature of 2300° F., for 70 hours. After cooling, the ware is dipped in the glazing material, and fired for 30 hours at 1800" F. Some of the decorating is done by the paper-transferring ])rocess, while the higher-])riced ware is hand-decorated. After decorating, the ware is fired for 12 hours at about 1100= F. Seven gas-fired kilns are in use. The factory produces about 1500 dozen pieces per day, and employs 70 men and women. Some ten years ago this plant used California clays, but found that the English clays gave better results. Kaolin from Hart, San Ber- nardino County, has been used recently, but is said to be too variable. Clay from Amador County has been tested with good results. In 1926, the company built a new plant at Slauson and Miles ave- nues, in Vernon. It is understood that both i)lants will be operated, but further details are lacking at this writing. 118 DIVISION OF MINES AND MINING St. Louis Fire Brick and Clay Co. Joseph Mesmer, president ; A. J. Mesmer, superintendent. Office and plant at 2464 E. Ninth Street. Los Angeles. This eompanj^ manufactures fire brick. Practically all of the clays in use at present are purchased from various sources, but the company owns a deposit near Corona that has been worked at various times in the past. The principal clays in use are the select main tunnel (sample No. 15, p. 264) and west blue (sample No. 23, ]). 277) from Alberliill ; the Emsco pink mottled (sample No. 71, p. 278) and the Lin- coln, No. 1-6 (sam])le No. 146. ]). 308). Some experiments were made with the Weiss clay from Glen Ellen, Sonoma County (samples No. 194 and 195, p. 262), but difficulties were encountered in securing satis- factory stnength. Both the auger and hand-pressing processes are in use, and the brick are fired in three down-draft bee-hive kilns, and two rectangular kilns, using oil as fuel. "^o Bibl: Cal. State Min. Bur. Prel. Kept. 7, p. 58. Santa Monica Brick Company.'^ E. A. Douglas, president; F. ^M. Taylor, vice president and treasurer. Office and plant at Twenty-third and Michigan streets, Santa Monica. The company owns 10 acres of clay land and manufactures common brick, red face brick, roofing tile, and red floor tile. The clay is a plastic, red-burning clay, underlying an extensive area from which numerous other manufacturers in the Los Angeles district secure clay for brick, hollow tile, roofing tile, and sewer pipe manufac- ture. There is no overburden. The deposit is now (1927) being worked by a power shovel against a 45-ft. bank, but the height of the bank may be increased in the future to 75 feet. The clay is trans- l)orted to the plant in cars operated by an endless cable hoist. Tlie plant is equipped with a 60-h.p. 24-in. by 24-in. American dis- integrator, a 150-li.p. American auger machine, having a rated capacity of 75.000 brick per day, an American automatic brick cutter, a 40-h.p. Pate-Koot-Heath roofing-tile auger, having a rated capacity of 10,000 tile per day, and a hand-operated roofing-tile cutter, in addition to the necessary elevating and conveying equipment. A hot-air tunnel drier is used, which operates on a schedule of 36 hours. Ten up-draft field kilns with permanent walls are used for firing. Both natural gas and steam-atomized oil are used. Normally, four kilns each with a capacity of 500,000, are used for firing brick, five kilns of 15,000 capacity each are used for roofing tile, and one kiln of 1000 sq. ft. capacity is used for floor tile. The brick are water smoked for three days, fired for four days, and allowed to cool for three (lays. Drawing and setting require about seven days. The finishing temi)erature at the end of the firing period is approximately cone 07 (975° C, or 1787° F.). The tile are water smoked for one day, fired for three days, and cooled in two days. One day is sufficient for setting and drawing. The company also makes liand-made ]\Iission roofing tile, which are dried in the open air. The plant is operated throughout the year, employing 60 men. A total of 350 h.p. of electric power is installed in the plant. The rated ' Data supplied through the courtesy of the company. CLAY RESOURCES AND CERAMIC INDUSTRY 119 c'aj)aeity of tl\e plant is T.l.OOU l)riek and 40 .s(iuares (lUU square ieet each) of roofin«r tile per day. Simona Brick Co. Walter R. Simons, president ; Robt. P. Isitt, vice president ; H. B. Howeth, secretary ; J. T. Crampton, treasurer. Office at 125 West Third Street, Los Angeles. Boyle Plant: The r>oylo i)lajit of the Simons company occupies a .^O-aere ])roperty at 1117 South IJoyk' Avenue, on the east bank of the Los Angeles River, a few blocks south of the Seventh Street yard of the Los Angeles Brick Co. Tliis plant is now engaged in the manu- facture of roofing tile exclusively. The claj' deposits on the property have been worked out by past operations, at least to such an extent that it is more economical to ship clay to this plant from the company's large pit at Santa ]\Iouica. Tn order to produce the wide variety of colors demanded by the trade of today, varying amounts of Emsco white i)lastic (sample No. 70. \). 272) and other clays fi-oin the Alberhill district are mixed with the Santa Monica material. Most of the ware is red, and the mixture for this ])ro(luet contains 75% Santa Monica clay and 25% of a pink burning fire clay, such as Emsco pink mottled (sam])I(' Xo. 71, p. 278). Liglit i)i]ik, cream, and buff tile are produced by adding \\\) to 90% of a light burning fire clay. The tile are formed by the stiff-mud process, with Mueller machines. Drying under .sheds requires nearly a Aveek. Firing is done in 12 down-draft bee-hive kilns. The lighter-colored tile, containing more refi-actory clay than the i-ed burned variety, are fired in one compart- ment of a double rectangular kiln, the dimensions of each compartment being 6 ft. by 20 ft. by 8 ft. A temperature of 2500° F. is required, and the heating period occupies three days. Kiln slabs, for supporting the tile during firing, are made of a mixture high in refractory clays, and are fired in the other compartment of the double rectangular kiln. Saxta Monica Plant: This plant is at Colorado Avenue and Twentj'-sixth .street, Santa jMonica. The property consists of 24 acres. The clay is similar to that on other properties in the same area ; see under Gladding, McBean and Company, Santa Monica Brick Company, and others. The soft-mud process is u.sed and the brick are fired in oil-fired field kilns. Simons Plant : The Simons ]ilant is advertised as being the largest plant in the world exclusively devoted to the manufacture of common brick. It is situated on a 400-acre tract at Simons, on the main line of the Santa Fe Railroad, 1 1 miles northeast of Montebello on the Southern Pacific Railroad. The clay is of excellent quality for the manufacture of common brick, and occurs in a superficial bed averaging 16 to 18 feet in thickness, underlain by fine sand. The clay is mined by steam shovel, and hauled to the ])lant in 6-yard cars by gasoline locomotives. Sixteen soft-mud ])ug mills and Potts presses are arranged in units of two machines each at such positions in the yard as to provide ample room for drying sheds l)laced so as to secure the mo.st economical trans])ortation of the brick from the presses, and to the kilns. The brick are dried in from 7 to 10 days, depending upon the weather, and are fired in gas-fired field kilns. An 18-arch kiln will hold 756,000 brick, and a 30-arch kiln hold'" 120 DIVISION OF MINES AND MINING 1,250,000. Both sizes are in use, tlie choice depending on requirements at the time of setting. The total capacity of the yard is 650.000 brick per day. The company has jHirchased a townsite, and has built homes for renting at a nominal rate to its 650 employees. Recreational facilities are provided, and every attempt is made to secure a permanent force of satisfied employees. Sta7idard Bricl' Co. J. V. Simons, president ; R. G. Simons, vice president ; H. W. Simons, secretary. OtBce at 102 Stimson Building, 129 West Third Street, Los Angeles. This company manufactures common red brick, and sewer brick, which are semi-vitrified common brick. Two yards are operated, one at Soto and Lugo streets, on the southern end of Boyle Heights, the other on Eucalyptus Street, in Ingle wood. Boyle Heights Plant : This property covers 8 acres. The material is a clay loam, 15 to 18 feet thick, underlain by sand. A steam shovel is used to mine the clay and load it into dump wayons, which are hauled to the di\y pans. The brick are made in Potts soft-mud brick machines, and are dried in air under sheds, requiring from three to four days. Three or four gas-fired field kilns are maintained, depending upon the demand. The brick in the arches are carried to the semi-vitrification point, Avith less than 10 /V absorption, are sorted out after firing, and sold as .sewer brick. The firing cycle is usually five and one-half days firing, and an equal time cooling. Mr. Welldon is foreman. Ingle\vood : At Inglewood the clay is of much the same character as at the Boyle Heights plant, containing lenses of sand and fine gravel, underlain by coarse gravel. The same brick-making ])rocess is used here as in the Los Angeles yard. Mr. Paye is foreman. Bibl : Cal. State Min. Bur. Prel. Kept. No. 7, p. 62. Torrance Bricl' Contpanij.^ T. H. Reed, president ; V. T. Pullman, secretary. Office address, Torrance. This company operates two jilants. Plant No. 1 : This plant is on the Plaza del Almo Boulevard, Tor- rance, and produces common red brick only. The property comprises 15 acres, consisting of a 30-ft. bed of red and yellow plastic clay, over- lain by about one foot of soil. The clay is mined by scrapers, which deliver to a hopper in the ])lant. From the hopper, the clay is elevated by a bucket elevator to rolls. Tlie roll jiroduct is elevated by a bucket elevator to wire screens, which return oversize to the rolls for regrind- ing and deliver undersize to a pug-mill. Tlie pugged clay passes to an auger machine, ecpiipiied with a wire cutter. The capacity of the auger is 60,000 brick per day. The brick are transported to drying sheds' in hand-trucks. Four open field kilns, fired with natural gas. are in use. The kilns have a capacity of 750,000 brick each. The plant operates throughout the year. Electric ])ower is used, the installed capacity being 105 h.p. Thirty men are employed. Plant No. 2. This plant is at Graves Avenue and Jackson Street, ^lonterey Park. Common brick, hollow tile, and red face brick are ' Data supplied by W. B. Tiiokcr. cli.vtrict mining: engineer, December, 1927. (LAY RESOURCES AND CERAMIC INDUSTRY 121 produced. The proi)erty consists of 20 acres of clay shale, from 20 to 30 feet thick. Tlie ca))acity of the plant is 60,000 brick ])er day, or its equivalent in other ware. Electric power is used, the installed capacity bein^r 120 li.p. Forty men are employed. Tudor Art Tile Company. H. C. Hill, C. J. Biddle, T. P. Cook, and Geo. Skee, owners, deo. Skee, suj)erintendent. Office address, 1204 Lane iIort<>a,ue Building, Los Anjieles. Plant at 5848.2 I^anta Pe Ave- nue, Los Antjeles. This company manufactures faience tile and inserts, usino- Alberhill clay. All special shapes are hand-molded in plaster molds, and an au' mill and auger machine, e(iui])ped with a wire cutter. Drying is done under sheds, and reiiuires 15 days (average) in summer, and a longer time in winter. Firing is done in Photo No. 26. Clay and shale deposit of McNear Brick Company, showing loading hopper. Marin County. (From State Mineralogist's Report XXll, p. 318, 1927.) two Hoffman continuous kilns, fired with coal screenings or oil coke. The kiln turnover i)eriod is 15 days, and actual firing requires from five to .six days. The finishing temi)erature is 2000° F. The capacity of the plant is 60,000 common brick i)er day. From 45 to 50 men are employed. Sample No. 198 was taken from the dry-pan feed. The superintend- ent stated that the sample was somewhat leaner than the normal feed to the plant as it had rained the previous night, and only the more sandy clay can be handled wlien the ground is wet. The test results are on page 329. Occasional seams containing calcite are encountered in the pit. These can be included in the mix if they are well distributed in the feed to the plant. Bibl : State Mineralogist's Reports VIII, p. 342 ; XII, p. 382 ; XIII, p. 615 ; XIV, p. 244 ; XXII, p. 317. Bull. No. 38, p. 249. Prel. Kept. No. 7, p. 64. 126 DIVISION OF MINES AND MINING Louis Sharhori^ 554 Broadway, San Francisco, has recently (1926) leased tlie Keiiiillard j)i'opei-ty (see posi) and was exi)ected to begin the manufacture of floor tile dui-inu 1927. No further data are available. Earlier Kkports. The status of operations or clay deposits noted in previous reports- is as follows : Maillard Ranch. Lagunitas. Now owned by the Lagunitas Develop- ment Company, 833 Market Street, San Francisco. "Clay deposit on Spring Creek, about eight miles nortliAvest of San Kafael." Tlie deposit is still undeveloped, and is ])robably common clay. Patent Brick Companij. Galliiias Station. This ])lant has been dis- mantled, and the company is out of business. The liidecker Tile Co., Twenty-fourth and Union streets, Oakland (see under Alameda County), occasionally crushes some of the old brick from this place for use in the manufacture of roofing tile. RemiUard Brick (U)mpanij. Greenbrae. "Shale and sandstone, ])rac- tically inexhaustible." Tliis plant was dismantled about 1911. The company operates plants at Pleasanton, Alameda County, and at San Jose, Santa Clara County (9 v.). Bibl (On ]\Iarin Countv clav resources) : State ^Mineralogist 's Reports V, p. lOS ; VllI, p. 342; XI, p. 253; XII, pp. 329. 382; XIII, pp. 506, 615; XIV, pp. 24-1-248; XX 11. ])p. 317-319. Bull. 38, p. 362 ; Prel. Kept. 7, p. 64. MENDOCINO COUNTY. General Features. Mendocino County joins Humboldt County on the south and is bounded by the Pacific Ocean on the west. Its area is 3453 square miles, and the population is 24,116 (1920 census). Lying in the Coast Range, the greater part of the county is mountainous and heavily tim- bered, except in the southeastern portion, through which flows the Russian River. Lumbering is an important industry. The rocks of the Coast Range within the limits of the county consist mainly of Franciscan (Jurassic), Chico (Upper Cretaceous), and various Tertiary sedimentary and metamorphic formations. The min- eral resources are largely undeveloped. Occurrences of asbestos, chromite, coal, copper, graphite, magnesite, and mineral water are known, as well as traces of gold, platinum, and silver. j\Iiscellaneous stone, coal and natural gas are produced in small amounts. Clay Resources. Common brick clays are available near the coast at the town of ]\Iendocino, and also at Ukiah. Brickyards were at one time operated in these places, and at Talmage, near LHviah, but there has been no pro- duction in recent years. The brickyard of U. N. Briggs, at Ukiah, has been out of business since 1922. The most recent production of com- mon brick was at the Mendocino State Hospital, at Talmage. See below. ' Laizure, op. cif., p. ?.19. = Especially in Prel. Rept. 7, p. 64. CLAY RESOURCES AND CERAMIC INDUSTRY 127 Mendocino State Hospital. Talmaj^^e.' A brickyard was operated here for a few yeai's to iiiajuifai'turc l)riek for use in eonstruetion work at the liospital. The elay eousisted ol' a hx-al (lei)osit of gravelly silt, about 10 feet deep, and covering an ai'ea of al)out one-half acre. It was mined with a ])low and sci-aper. The plant is eciuipped with a disintegrator, conveyor, pug-mill, and auger machine, with a wire cutter. The lack of screening equipment reduced the capacity of the machinery to 8000 brick per day instead of 30,000, on account of gravel in the clay. Firing was done in open field kilns. The ])roduction cost of the brick was stated to be $11.50 per thousand. There has been no production since 1924, as it was found tiuit concrete construction is cheaper, with cement at $2.28 per barrel, delivered. l'>ibl: State Mineralogist's Kept. XIV. p. 415; State Min. Bur. Prel. Kept. 7. p. 04. MERCED COUNTY. General Features." ^Merced County is situatetl lU'ar the geographical center of the state. It is bounded on the north by Stanislaus County, on the east by ]\Iari- posa, on the south by Madera and Fresno, on the west by Santa Clara and San Benito counties. It has an area of 1995 scjuare miles and sup- ports a population of 24,579 (1!)20 census), ^lost of the land is culti- vated, and much of it is irrigated, there being extensive irrigation systems covering the valh'y lands. ]\Ierced is essentially an agricultural county. The greater part of the county lies within the San Joacjuin Valley, and is comi)osed of unconsolidated sands, gravels, and clays of (^uateinary age. Along the eastern edge of the county there is a narrow belt of Tertiary formations, represented mainly by clays, shale and massive sandstone. On the western side of the county ('retaceous sand- stones and shales appear, and as the western boundary of the county, near the summit of the Coast Kange, is ap])roache(l, Franciscan rocks of •Jurassic age are exclusively in evidence. These consist mainly of slates, cherts, sandstones, schists, and serpentine. Both metallic and nonmetallic minerals have been found and pro- duced in Merced County. Among the former are gold, platinum, silver, cop])er, and a few ])ounds of lead. Crushed rock, gravel, sand, clay, and clay products are the chief nonmetallics. In addition to these the occurrence of a few other minerals has been noted, such as cinnabar (quicksilver), stibnite (antimony), barite, calcite, diatomaceous earth, magnesite, asbestos, manganese, coal, and soda niter, but for the most part these are entirely undeveloped and probably most of them do not occur in marketable quantities. Miscellaneous stone, including crushed rock, gravel, and sand, cement, brick and tile, are at the present time the principal mineral products. Structural materials of this nature will contribute almost exclusively to the future mineral output of the county. Clay Resources. No commercial deposits of high-grade clay have been found in the county, notwithstanding intensive investigations on the part of the ' Information secured through the courtesy of Dr. Donald R. Smith. 2 From Laizure, C. Mc-K.. Merced County: State Mineralogist's Report XXI. p. 173, et seq., 1925. 128 DIVISION OP MINES AND MINING I'alifornia Pottery romi)any and the Yosemite Portland Cement Com- pany. The hitter company recently built a cement plant near ]\Ierced and conducted an elaborate search for high-alumina clay, low in iron, but were finally forced to import this material from the lone district. There are a few remnants of the lone formation in the foothills of Merced County. These have not been thoroughly prospected, but there seems little reason to hope for commercial clay dejiosits in them. Clay suitable for the manufacture of common brick and hollow tile is available in the vicinity of Merced. A brickyard operated in Pierced from 1905 to 1910. The clays from various i)laces are now being used by the California Pottery Company (see post), the Yosemite Portland Cement Company, and the Craj'croft-Herold Brick Company of Fresno. The latter company mines clay from a deposit six miles south of Merced, and shii)s to its jilant in Fresno. California Pottery Co. F. A. Co.stello, president. General of^ce. Mills Building, San Francisco. Plant at Merced. The company also operates a plant in Oakland, Alameda County. The Merced plant is in the southern outskirts of Pierced, between the state highway and the Southern Pacific railroad. The ])roducts of the plant are roofing tile, hollow tile, and some 3-in. to 6-in. drain tile. Red, buif, and pink ruffled face brick were formerly made. The local clav is mixed with clav from the company's pit near Valley Springs, Calaveras County (samples Xo. 202-204. pp.' 299 and 337), and with red-burning clay from the Xatoma Clay Company in Sacramento C^ounty (.samples No. 210 and 212, p. 337). The local clay is a valley silt, and is mined to a depth of 10 feet with team and scrajier from a ])it adjoining the plant. It has in.sufficient bonding strength and plasticity to be used alone, and at least 359c of the Valley Si)rings clay, or an e(|uivalent amount of Natoma clay mu.st be mixed with it. The plant is equipped with a 10-ft. Raymond dry pan, one American number 290 auger machine for hollow tile and face brick, one American No. 233 auger for roofing tile, a 20-tunnel American waste-heat drier, and eight 30-ft., oil-fired, steam-atomized, round down-draft kilns. The dryer cycle is 36 hours. When there is insufficient dryer capacity, .some ware is dried on the drier floor. Each of the kilns has a capacity of 125 tons of hollow tile. 100 tons of Sierra roofing tile, or 90 tons of Spanish roofing tile. Firing requires 72 hours, to a maximum tempera- ture of cone 4—5 (1170° C.) for buff -colored ware, and to cone 2 (1135° C.) for red-colored ware. Seventy-five per cent of the output of the plant during 1925 was roofing tile. The output of drain tile is very .small. The plant is handicapped by the fact that clay must be brought in from the north, and at the same time, the principal market for the ])roducts are to the north. Forty -three men are emploj'ed. M. Goldman^ of Merced is the owner of large land holdings in the eastern ])art of the county, and it has been reported in the past that white clay, .suitable for the manufacture of pottery, occurs on this prop- erty in the vicinity of Merced Falls. The holdings have not been thor- oughly prospected, but the investigations that were made failed in find- ^ Laizure, C. McK., op. cit., p. 179. CLAY RESOURCES AND CERAMIC INDUSTRY 1 29 iii^' any liij^li-^'j'adc clay; llic malciial hriiii;- apparently a silt (h^jMtsit of iiKJcfinito coiiiposil ion, i-atlisits liav(> bocii i-t']»()i-1('(l from 'W o S., 11. 14 10. 'riicir char- acter and value have not been determined. J5ibl (Merced Countv clav resources) : State iMineralogist's Keports, XIV, p. 605; XXl, pp. 175, 177-179. Bull. 38, pp. 217, 250; Prel. Kept. 7, p. 64. MONTEREY COUNTY. General Features.' Montere.y is one of the central coast counties, extending from the Pajaro River, MJiicli emi)ties into Monterey Bay, south to the sixth Standard ParaUel. It i.s bounded on the north by Santa Cruz County. San Benito, Fresno and Kings counties adjoin it on the east, and San Luis Obispo County bounds it on the south. Its area is 3330 square miles and its population 27,980 (1920 census). The main line of the Southern Pacific railroad, coast division, runs through the count}^ con- necting it with San Francisco and Los Angeles, as also does the state highway, a concrete paved road. Connecting county roads are kept in good condition, and it is only in the more remote mountainous sections that economic transportation becomes a problem. Tlie completion of the ])roposed road along the coast, connecting Monterey and San Luis Obispo, now open from the north to a point 18 miles beyond Big Sur and from the southern end as far norlli as Salmon Creek, will open up a lai'ge area which has heretofore been accessible only by water or steep trails, and one whose mineral resoui'ces are scarcely known. Among the principal topographic features is the great central Salinas Valley, the largest of the intermountain valleys of the coast region, being about 100 miles long by 6 to 10 miles in width, and lying parallel to th(> coast. P>etween the valley and the coast rises the Santa Lucia ]Mou)itain Range, which culminates in a number of peaks, some reacliing nearly 6000 feet above sea level. Along the eastern side of the valley, and with their crests forming the eastern boundary of the county, are the Gavilan and Diablo ranges. Among the smaller valleys are the San Lorenzo, San Antojiio, Cholame, Carmel, and Nacimiento. In each of these the ])rincipal axis extends noi'tli westerly, parallel witli the general structure of the mountain ranges. Geology. The geology of most of Monterey County is described and ma])ped in Bulletin No. 69 of the State Mining Bureau, 'Petroleum Resources of California,' and the folio accompanying it. It is also shown in lesser detail on the Geological Maj) of California (1916). The Santa Lucia Range has a core of granitic rock. This is exposed in Santa Lucia Peak at an elevation of 5967 feet, and throughout the territory between Carmel River and Sur River, either along the coast or in the river cuts. Limestone and gneiss overlie the granite in places, and make up Pico Blanco, Ventana Cone, Marble Peak, Twin Peak, and Cone Peak. Most of the area from Mill Creek southward to Three Peaks and bounded on the northeast bj" Nacimiento River is made up of Fran- » Laizure, C. McK., Monterey County: State Mineralogist's Report XXI, p. 23, 1925. 9 — 54979 130 DIVISION OP MINES AND MINING ciscau sandstone and shale, witli intrusions of serpentine. It is in the region of these serpentine intrusions and the later intrusive acid dikes that tlie important mineral deposits of the Los l>urros district are found. The geology of tlie Los Burros district has been described in considerable detail by Ilill.^ There is evidence throughout of much faulting, and the precipitous coast follows a fault line. Monte- rey sandstone and conglomerate flank the mountains on the soutliwest side of Nacimiento River, and dip towards the valley. Most of the older sediments exposed east of the Nacimiento consist of Monterey shale, which is considerably folded east of Jolon. Along the coast, resting unconformabl}^ on the granite and Franciscan rocks, are raised beach deposits. The settlement of Gorda is located on the most recent of these terraces. This terrace is noticeable in Willow Creek, one-half mile back from its mouth, and also along the coast north of Gorda. These terraces are important in relation to placer gold. It is thought that the placer deposits near Jolon originated in a similar manner. In the northeastern part of the county, in the Gavilan Range, granite occurs associated with gneisses and schists. In places these rocks con- tact with massive beds of metamorphosed limestone, and dolomite is commonly associated with them. Feldspathic segregations give rise to commercial deposits of feldspar along the range as far south as the Pinnacles. In the vicinity of the Pinnacles there is a small area wdiere volcanic activity has taken place and extrusive volcanic rocks are in evidence. Farther south Tertiary sandstone and shales predominate. A long, narrow belt of the Franciscan rocks, including slates, sand- stones, and much schist and serpentine, extends from Priests Valley southeastward beyond Parkfield. AVorkable coal beds are exposed in the vicinity of Priests Valley and the principal quicksilver deposits occur in the Franciscan, not far from Parkfield. The following commercial minerals are of record as occurring in Monterey County: Arsenopyrite, barite, bitumen (asphaltnm), calcite (limestone and marble), ehromite, cinnabar (quicksilver), clay, coal, copper, diatomaceous earth, dolomite, galena, garnet, gold, graphite, gypsum, magnesite, magnetite, malachite, metacinnabarite, molybdenite, orthoclase (feldspar), psilomelane (manganese), quartz, salt, serpen- tine (asbestos), and stibnite. Not all of these have been produced in commercial quantities, however, nor is it known that all occur in suf^- cient quantity to be of value. About ten other species of miiieralogical interest only have also been noted. Clay Resources. No commercial deposits of high-grade clays have been discovered in the county. Common brick clays are not abundant, but there is little doubt that suitable deposits can be found if needed for local purposes. A clay pit and brickyard were at one time operated on a small scale at the south end of Salinas. The only clay-working operations in the county at present (1927) are two hand-made roofing tile plants, which are described below. Area Hoofing Tile Plant. Joe Area of Castroville owns and operates a small hand-made roofing-tile plant one mile east of Castroville on the 1 Hill, J. M.. The Los Burros District, Monterey County, California : U. S. Geol. Survey Bull. No. 735-J, 1923. CLAY RESOURCES AND CERAI^tlC; INDUSTRY lol Salinas road. The property covers one acre. The clay deposit consists of 18 ft. of yellow plastic clay, underlying one foot or less of black adobe. See sample No. 117, ])age ;i24, for test data on the clay. Tlie clay is mined ])y hand and is fed to a horse-driven ]ing-mill. After the l)uyged clay is aged for a few days, the tile arc shaped by hand over wooden forms, and are then dried in air under sheds. The clay is excessively plastic, and in the cool moist climate of the region, drying is very slow. The tile are fired in an oil-fired rectangular u])-draft kiln. The capacity of the plant is 500 tile per day, and three or four men are employed. Mr. Area reports that good roofing tile clay occurs on the Martin ranch near the Carmel mission. It was u.sed by the Indians in making roofing tile for the IMission. ]\Ir. Area attempted to establish his plant there but found that the land was too valuable. Monterey Mission Tile Co. II. L. Watson, i)resident; T. II. Bane, secretary treasurer. The new plant of the jMonterc}- ]\Iission Tile Com- pany is near Seaside, and about two miles north of Del Monte. The property covers thi-ee acres. The products are red-burned roof tile, floor tile, and step tile, all of which are hand-made. The clay is mined by hand methods from the Thomas Field ranch on the Laguna Seco grant, at a point 5.5 miles toward Salinas from the junction of the Salinas road and the Santa Cruz road just north of Del IMonte. The total haul to the plant is seven miles. The clay is a black adobe, 10 feet deep, covered with 2 feet of sandy soil. Sample No. 214 was taken from the clay in storage at the plant. See page 327. At the plant, the clay is mixed with approximately 20% of grog con- sisting of ground rejects from the kiln, pugged in a Patterson vertical pug-mill, and aged for at least three days before molding. A 5-hp. motor drives the grog crusher and the pug mill. The tile are shaped by hand with Mexican labor, and are dried under sheds. The drying time varies widely Avith climatic conditions, but usually requires at least two Aveeks, on account of the cool, humid atmosphere generall.v prevailing in this region. The tile are fired in a cylindrical up-draft kiln, 13^ feet in diameter in the lower 6-ft. section, tapering to six feet in diameter in the upper 5-ft. section, and finally tapering to four feet in diameter at the throat. The kiln will hold ai)iU'oxinuitely (iOO roofing tile. Tt is fired with four oil burners, placed in pairs at opposite sides of the kiln. The oil is preheated to 120° F. in electric heaters placed in the pipe line, and is atomized with air from motor-driven blowers. Four base-metal thermo- couplos. with a multiple rccordci-, are used to control the firing, in addi- tion to Orton standard cones. The niaxinnnn temperatures recorded at the end of firing are 1830° F. on the bottom, and 1470° F. on the top of the kiln. Firing requires 32 to 38 hours. The product is distinctly different in appearance from machine-made tile, and from most of the hand-made tile produced in the state, on account of the irregular texture and the play of colors to be seen on each individual tile. The owners of the plant were formerly builders in the district, and the tile plant is the outgrowth of a local desire for more artistic effects than could be obtained with the tile previously on the market. Since the tile are made by an expensive process, they are 132 DIVISION OF MINES AND MINING only to be seen on some of the finest residences in Carmel and Pebble Beach. From 8 to 10 men are emploj'cd when the plant is in fnll operation. Bibl: State Mineralogist's Report XXI, p. 57, Jan. 1925. Miscellaneous Deposits. Echstine Deposit. Mrs. G. P. Echstine, Pleyto. In T. 24 S., R. 8 E., M. D. M. An ocenrrence of white plastic clay had been reported to the Burean. The deposit was investigated in September, 1926, and was found to consist of a plastic clay that is graj'ish white when dry, but darkens considerably when wet, and fires to a red color. The property is difficult of access, and is some 18 miles from the railroad, hence the clay has no possible commercial value. Heins Lal-e Deposit. Owner, Martha E. Bardin, Salinas. Tlie bot- tom of Heins Lake, now dry, situated about two miles southeast of Salinas, is reported to be composed of blue clay. There is about 300 acres in the deposit, and it is said to average four feet in depth. ^ No investigation was made by the author. Jens Deposit. Chualar. A supposed deposit of clay from wliieli it was reported that several thousand tons had been shii)pe(l. An investi- gation showed that the material is low-grade feldspar. Bibl (Clav resources of Monterey County) : Cal. State Min. Bur. Bull. 38, p. 250; Prel. Kept. 7, "p. 65; Kept. XXI, pp. 29 and 57. NAPA COUNTY. General Features. Xapa County, witli a hind area of 783 square miles, runs nearly to a point at both extremities. It is bounded on the east by Solano and Yolo counties and on the west by Lake and Sonoma counties. Its southerly end touches San Francisco Bay. The main drainage system of the county is that of the Napa Valley, which is a rich agricultural section, and is served by a branch line of the Southern Pacific railroad, extending from San Francisco Bay to Calistoga, in the northwestern corner of the county. Mt. St. Helena, a prominent landmark, is in the northwest corner, at the junction with Lake and Sonoma counties. The principal geological formations in the county, in addition to Recent sediments in the valleys, are Franciscan (Jurassic) slates, sand- stones and serpentine, Miocene sandstones and shales, and Tertiary voloanics.- The in-incipal mineral resources include quicksilver, inineral water, miscellaneous stone, and magnesite. Occurrences of diatomite, lime- stone, copper, iron, chromite, gold, silver, and mineral paint have been noted. A cement i)lant at one time operated at Napa Junction. Clay Resources. Common clays .suitable for brick manufacture occur in the Napa Valley. Previous to 1890 there was a plant in operation near Napa, 1 Laizure. C. McK., op. cit., p. 29. - Smith, J. P., The geological formations of California : Cal. State Min. Bur. Bull. 72, and Geological Map. CLAY RESOURCES AND CERAMIC INDUSTRY 133 where brick and drain tile were made. The cement plant at Napa Jnnction used local clay in cement manufacture. An interesting occurrence oi" kaolin is described at considerable length below, not so much for its present value, which is doubtful in the pres- ent state of development, but because of its significance in encouraging further prospecting for commercial deposits in tliis region. Clark and Mai\'ih Kaolin Mine. This property, referred to in a previous report ^ as a 'china clay' deposit, owned by W. R. Teale, has been acquired by J. R. Clark and C. L. Marsh of Calistoga. The propertv includes the following areas: S.^?, SEj, Sec. 12, and Ni NE^, Sec. 13," T. 8 N., R. 7 W.. and the Si SW], Sec. 7, NW^ NWj, Sec. 18, and the diagonal (NW.-SE.) NEJ 5sE\ NW-1 Sec. 18, in T. 8 N., R. 6 W., M. D. M., a total of 300 acres. The principal workings lie near the top of a hill, 3.5 miles by road south of Calistoga. Some road grad- ing is necessarv before trucks can be run to the mine. Photo No. 27. Clark and Marsh Kaolin Mine. Main workings, facing west. Note scrub brush over deposit, and timber in left background on other formations. Calistoga, Napa County. The deposit is a residual kaolin formed by the alteration of a rhyolitic rock that has a wide distribution in the region. This rock forms the crest of certain of the low hills south of Calistoga, and is distinguishable by its white color, and its hardness at the surface, where silicification has taken place. The debris covering the formation is very thin, and is composed of irregular grains and fragments of the silicified rock itself, with only enough soil to support a scattering growth of shrubs, principally manzanita, w^hereas the soil resulting from the decomposi- tion of most of the other formations in the region is adequate to support a growth of hea^7- brush and trees. This characteristic is illustrated in photo No. 27, wliicli is a view of tlie main workings. Plate VII is a sketch map of the main workings, from which over 200 tons of kaolin have been removed, some of which has been shipped to 'Cal. State Min. Bur. Prel. Kept. No. 7, p. 65, 1920. 134 DIVISION OP MINES AND MINING various clay products manufacturers for testing. An examination of the -workings shows that the progress of kaolinization has been very erratic. The hard, silicified zone at the surface is from one to three feet thick. Below this, the kaolin varies from a non-plastic aggregate of partly-altered feldspathic grains, to a fine-grained mass that has fair plasticity. In places, following lines of fracture, the kaolin is heavily stained bj' iron-bearing minerals, but between these discolored areas, the mass of the material is practically w'hite in color. The most discouraging feature of the workings is that most of the headings end in material that is badly iron-stained. It is estimated that 20% of the material exposed in the underground workings is contaminated with iron. The iron-stained portions are distributed in such a manner as Plate VII ^/KETCH MAP or CLAR/K-^'^'^ MARSH KAOL/N M/NE CAL.'STOOA, CAL/F. 5 Xo. 6;") was taken for testing. See page 322. Garhn- Brick and Tile Co. II. Garber, president, Olive. The com- pany controls 6 acres, one-half mile east of Olive, on the Orange County Park road. Common brick, hand-made roofing tile, floor tile, roof dressing and a dust product for molding sand are manufactured. All of the clay used is mined from a pit on the property. Material is transported from the clay pit by a drag scraper to the plant, where it passes through rolls, is elevated to storage bins. The brick are made by the soft mud process. A pug-mill prepares the clay for the brick press as well as for the tile plant. The brick are conveyed by a cable convej-or to drying racks. After drj'ing, the brick are burned in field kilns, using natural gas as fuel. Both roof and floor tile are hand molded, air dried under sheds, and fired in two down-draft kilns. The rated output of the plant is 2000 roof tile and 25,000 brick per day. The ecpiipment includes a 30-h.p. boiler, Ingersoll-Rand compressor, Blake type crusher, screens and elevators. From 25 to 30 men are employed. Bibl: State Mineralogist's Report XXI, p. 65. Gladding, McBean and Company. Office of Southern Division at 621 South Hope Street, Los Angeles. This company, through its merger with the Los Angeles Pressed Brick Com))any, now owns the Goat Ranch, noted in previous reports^ as containing an important deposit of flint fireclay. The location of tiie property is shown on Plate X, under Riverside County. The property consists of 1700 acres, and lies in an extremely rugged portion of the Santa Ana ^Mountains, south of Gypsum station on the Santa Pe i-ailroad. The deposit lay idle for many years, but since 1925 considerable development work has been done, which has demonstrated the presence of large deposits of flint fireclay and red-burning shale in the Upper Chico (Upper Cretaceous) formation. A view of one of the fireclay exposures is shown on ])hoto Xo. 28, and one of the red shale prospect pits is illustrated on photo No. 29. The flint fireclay, when dry, is gray to black in color, and has a conelioidal fraetur(\ The lighter-colored varieties have very much the appearance of chert, but can easily be scratched with a knife, and when ground with water, develop moderate plasticity.- It contains from 34% to 40% of alumina, and is highly refractory. Sample No. 282 was taken for testing, but should not be considered as representative of the deposit, as it is a grab sample from development workings. The results are on page 282. Sample No. 221 (page 330) of similar material, 1 Prel. Rept. 7, p. 66, and Rept. XXI, p. 66. Listed under "Los Angeles Pressed Brick Companv." - In this connection, see Walker, T. C, The Effect of Pine Grinding on an Indurated Clay: Jour. Amer. Cer. Soc, Vol. 10, pp. 449-450, June, 1927. 142 DIVISION OP MINES AND MININO but of much poorer quality and containing a high percentage of iron, was also tevSted. The red-burning shale has been prospected at a number of points on the property. It is of value in the manufacture of red-burned vitri- ■•^ * ^"^^ A\ f^. t X I Photo No. 2S. Flint fire clay at iiortal of tunnel, Goat Ranch, Gladding. McBean and Company, Orange County. (Sample No. 282.) tied ware, such as sewer j)ipe and paving brick. ISample Xo. 223 (p. 343) was taken and tested. La Bolsa Tile Company. G. W. Moore, president ; A. W. Griffith, secretary and manager ; E. R. Bradbury, superintendent. Home office, CLAY tTESOURCES AND CERAMIC INDUSTRY 143 Huntington Beach. This company lias been established for twenty years. The j)lant anci clay pit are two miles north of Huntington Beach at Weibling siding on the Soutliern Pacific Railway, adjoining the northern edge of the Huntington Beach oil field. The company r'^ -v' '* ^^W^- ^^m^ljmMXi- ■ r ^^™gi. !U9.Jim^ 'JV^^^^^^^^I^^^^^^^^^^^^^^^I ^^^^^^^^^^^^|Q|7 Jc "" 1 ■Bj^^^^ ' Photo No. 29. M -M 2 pit, Goat Ranch, Gladding, McBean and Company, Orange County. Photo No. .30. Plant of La Bolsa Tile Company, Weililinp, Orange County. (From State Mineralogist's Report XXI, p. 65, 1925.) o^\Tis 31 acres in Sec. 35, T. 5 S., R. 11 W., S. B. M. The products are drain tile from 3 to 20 inches in diameter, hollow building blocks, common brick, and more recently, ruffled face brick. Photo No. 30 is a view of the plant. 144 DIVISION OP MINES AND MINING The cl;i,y is iiiiiicd lo a (l('i)th of five feet by a Pordson tractor, using a harrow for loosening and a scraper to deliver it to a hopper, which feeds a dry pan. An elevator delivers tlie ground material to a hopper which feeds a short inig-niill from which the clay passes to an auger machine. The plant is equipped with two auger machines which are used to shape all products except drain tile of 10 inches diameter or larger, for which purpose a vertical steam press is used. The drying sheds are heated by hot air forced by a blower through flues under the floor. The air is heated either by the exhaust from the kilns or by exhaust steam. Tlie drying sheds have a storage capacity of 60,000 tile. The drying cycle is from 24 to over 60 hours, depending on tlie size of the ware. The plant is equipped with three 28-ft. down-draft kilns, with a capacity of 70 to 80 tons of material each, and one 32-ft. kiln, with a capacity of 100 tons. Natural gas is generally used as fuel, but the plant is equipped for oil firing when needed. The firing cycle is 72 to 80 hours to a maximum of 1650° F. The finished products are dense and hard with a good red color. Ten men are employed. Bibl: State Mineralogist's Report XXI, p. 66; Prel. Rept. No. 7, p. 66. Olive Roofing Tile Co. Ramon Flores, owner. This is a small plant near that of the Garber Brick antl Tile Com})any. Hand-made roofing tile is the only product. Surface clay from the property is utilized. One kiln is in use. The plant is a Mexican operation, and as many as 24 men are employed at times. Orange County Brick and Tile Company} F. C. Krause, president; Charles Page, secretary; W. J. Carmichael, general manager. The company owns nine acres in Sec. 9, T. 4 S., R. 10 W., within the city limits of Anaheim. The company is manufacturing building brick, and also produces sand for building purposes. The material used is unconsolidated sand. The sand is mixed with lime and cement in the following proportions : Common brick: lime 7|%, cement 2%. Face brick: lime 10%, cement 5%. Material from the sand ])it is transported by drag-line scraper to a hopper, from Avhich it goes to a })ucket elevator, elevated and then ])assed through a revolving screen. Here it is sized into three different sizes ; the over-size and the minus 8-mesh going to storage bins, the fine sand to wet-grinding pan, where it is ground and then elevated to two bins, then sent on to the mixer from which it is fed to two American clay brick rotary presses. One press has a capacity of 8000 brick, the other 17,000 brick. The brick then are loaded on to cars and given 10-hour heat treatment under 125 pounds pressure in two Hardinge cylinder driers. Tliese driers are 80 feet long by 6 feet in diameter. Heat for cylinder driers is furnished by 70-h.p. boiler, oil being used as fuel. The other equipment is driven by electric motors. Ten men are employed. ^ By W. B. Tucker, 07;. cit., p. 60. While not a ceramic operation of the type being con-^iidered in this report, this descriiition i.s included here as of general interest, " it is tvnical of similar cjpeT'ations in various parts of the state. CLAY RESOURCES AND CERAMIC INDUSTRY 145 The Vitrefrax Company (O'Neill Ranch Fire Clay Deposit). On the Raiiclio de Santa ^Farj^arita, the <>reater portion of -wliich is now owned by the Jerome O'Neill I'aiiiily, are several excellent showings of high-grade fireclay, one of which has been leased and developed within the last few j^ears through the efforts of the Vitrefrax Company of Los Angeles. This deposit is 10.2 miles by i-oad east of San Juan Capis- trano, in Gabino Canon, close to the San Diego County line. The material consists of a white and blue-gray fireclay high in alumina, and quite free from ii'on stains. It is known locally as a bone clay, and in fact corresponds in analysis to that of typical bone clays, but without the distinctive jiisolitic structure of the type clays. The fire- clay bed is overlain by a thin bed of black carbonaceous ])lastic clay, which separates it from the overlying loosely con.solidated sandstone. Underlying tlie fireclay is a mottled ])lastic clay, similar in general appearance to the Alberhill i)ink-mottled variety. The thickness of the Photo No. ;>1. Vitrefrax Co. Entrance to upper chamber workings, O'Neill Ranch clay depo.sit. Orange County. (Sample No. 62.) fireclay, as exposed in the workings, is from 10 to 15 feet. The bed is flat-lying, with a slight westerly dip. A view of the deposit is shown on plioto No. 31. The clay is recovered by chamber mining, using posts where needed to support the overburden. At the time of visit, in July, 1925, an area of 70 by 25 feet had been mined and a 100-foot tunnel had been driven to the west of the chambers, and at a lower level, with the object of providing for gravity loading of small mine cars, by means of a raise to the clay bed. One of these raises had been driven nearly to the roof of the clay, and demonstrated that the total thickness of clay above the tunnel is nearly 20 feet. At several other localities in the vicinity are exposures of various grades of clay. It is likely that in the future, important clay beds will be developed and mined. 10 — 54979 146 DIVISION OF MINES AND MINING Samjile No. 62 was taken for testing. See page 259. Bibl (Clay resources of Orange County) : Repts. XV, 519; XXI, pp. 65-67. Prel. Kept. 7, j)]). 66-67. PLACER COUNTY. General Features.' Placer County extends from the Sacramento Valley on the west for a distance of 80 miles to the Nevada state line on the eastern slope of the Sierra Nevada, including the larger part of Lake Tahoe. The total area is 1395 square miles. The elevation increases gradually from near sea level on the west to mountain peaks 8000 to 9000 feet high along the summit of the range on the east, then descends to 6225 feet along Lake Tahoe. There is a corresponding variation in climatic conditions. The western part of the count}' below an elevation of 2500 feet supports most of its industries and nearly all of the population of about 20,000. In this region snow seldom falls below 2000 feet elevation and never lies on the ground below that elevation. The county seat, Auburn, is at an elevation of 1360 feet, and the di.strict from there westward through Newcastle, Penryn, Loomis and Rocklin is the most important deciduous fruit producing area in the state, Newcastle being the leading shipping point. The soil is mainly decomposed granite and granodiorite on the west and amphibolite schist and diabase near Auburn and to the east, until the granodiorite of the high mountains is reached. The Ogden route of the Southern Pacific system traverses the county from the Sacramento line to the summit of the Sierra Nevada, passing through the principal towns, and the Oregon branch of the same rail- road, leaving the main line at Roseville, passes northward through Lin- coln, serving the farming and clay Avorking industries there. Two state highways run about parallel to the two lines of railroad, one eastward from Sacramento over the mountains, and the other northward from Roseville along the east side of Sacramento Valley. A third state high- way runs north from Auburn to Grass Valley and Nevada City, in Nevada County. Taking its name from the Spanish, because of the richness of its sur- face gold placers, the county showed a great diversity of mineral resources at an early date, and was distinctly a mining county until about 1890, when fruit raising began on a large scale for eastern ship- ment. Lumbering and the summer grazing of cattle in the higher mountains have been less important industries. Gold has been the principal mineral ]n-oduct of the county, but since 1920 the value of the pottery clay and brick production has exceeded that of the gold production. Since 1922, the value of pottery clay alone has been greater than that of gold. Other mineral products that have been produced commercially in recent years include miscellaneous stone, granite, silica (quartz), chromite and copi)er. Small tonnages of asbestos, manganese ore, magnesite, mineral paint and soapstone have been shipped at various times, and the limestone production of the county was at one time of importance. Clay Resources. A remnant of the lone formation, containing valuable clay deposits, occurs on the edge of the Sacramento Valley at Lincoln. Since 1875, > Logan. C. A., State Mineralogist's Kept. XXIII, pp. 235-237, 1927, CLAY RESOURCES AND CERA:\riC INDUSTRY 147 this area lias been a elay produeiii^' and clay woi'kin*; center. Present prodnction from the district is between 12;"), ()()() and ir)(),0()0 tons annnally. Other remnants of the lone foi-mation occnr at varions ])laees in the county, ami cla\s have been found in other formations, but none of these have led to the discovery of commercial deposits. On account of the fact that the active clay workinji; industry centers about Lincoln, the discussion of the elay resources of the county is divided into two sections: the Lincoln District, and ^liseellancons Deposits. Lincoln District. At Lincoln is one of the three most inipoHant clay dejiosits in the state. The deposits undei-lie a fjroup of low hills that rise to a maxi- mum of 80 feet above the alluvial jilain of the Sacramento Valley. The clays are a remnant of the lone formation which was jirotected from erosion by a capping of andesite-agglomerate. As shown by C. N. Schuette,^ and illustrated in the vertical section through a portion of the jiroperty of the Clay Cor])()i-ation of Califoinia, |)late IX, the upi)er clay beds have been removed by erosion a short distance beyond the limits of the ])resent lava cap. Since the i)eriod of erosion, gravel, sand, and soil from the rivers and flood plains of the Sacramento Valley have raised the floor of the valley to its present level. In some ])laces the recent dej^osits abut against the margin of the lava cap, and in other {)laces they lie against the gently-slo])ing surface of erosion of the uj)])er clay beds, thus affording some exposures of elay which aided in the original discovery and development of the de])0sits. The clay beds lie ])ractically hori;^ontal, and are characterized by remarkable uniformity in thickness and quality- over large areas. Several different beds can be differentiated and are of sufficient thick- ness to permit separate mining. The ceramic ])roperties of the clays may be summarized as follows: The drying and fii-ing shrinkage is high, but shrinkage takes })lace with little danger of cracking. The fusion point lies between cone 28 and cone 33 ; fired colors range from light buff to light red; knife hardness develo])s near cone 1; vitrifica- tion is well advanced (less than 3';> absorption) at cone 13; and fired strengths are good, but with the highly-grogged mixtures necessary to avoid excessive shrinkage, the body strength may not be so high as is desired. The princijial uses are for architectural terra cotta, fire brick and stoneware. Clay Corporation of California, .lolin T. Koberts, ])resident. Home office, Kialto Building, San Francisco. The mining property of the Clay Corporation of California, a subsidiary of the Stockton Fire Brick Company, has recently been described by C. N. Schuette.- The descrip- tion that follows is ])artly based on ^Mr. Schuette 's article, and partly upon notes made by the Avriter when the property was visited on August 13, 1925, and again on June 25, 1926. The property is in Sec. 4 and 9, T. 12 N., R. 6 E., M. D. M. The area is covered by andesite-agglomerate from its southern boundary to ■ Engineering Principles Applied to Exploitation of a Clay Deposit, Eng. and Min. Jour.-Press. Vol. 121, p. 964, June 12, 1926. - Op. cit. 148 DIVISION OF MIXES AND MINING Plate VIII. General arrangement of quarry and plant of the Clay Corporation of California, Lincoln, Placer County. (Reprinted by i)erniission of Engineering and Mining Journal.) I CLAY RESOURCES AND CERAMIC INDUSTRY 14U K2- O o X 150 DIVISION OP MINES AND MINING a line roiij;lily i)ar;illel to and ai)i)roximately 1600 ft. north of the Lineoln-Marysville ]ii<>'hway. Drilliiiji' and test ))ittin^' shows that all of tlio chiy beds exposed in tlie adjoining property of the Lincoln Clay Prodncts Co. on the south ])ersist on an even grade, thickness, and character under the area covered by the lava flow, but that they do not ])ersist northward as they had been removed by erosion before the deposition of the valk\y sediments. This condition is shown in the generalized north-and-south cross-section, plate 9. Over 1,000,000 tons of clay corresponding to the Lincoln Clay Products Co. No. 1-6, have been developed. The general arrangement of the quarry and i)lant is shown on plate VIII. Since the stripping is as thick or thicker than the underlying clay, the trackage was laid out to place the waste dump as near the pit as possible. The quarry starts on the north slope of the hill and is carried parallel to the trend of the hill, thus giving a pit face of sufficient Photo No. 32. End-cut during preparation of pit of Clay Corporation of Cali- fornia, at Lincoln, Placer County. (Samples No. 152 and 153.) length to yield a full season's tonnage at one cut. The pit face is 1700 feet long. , The ])it equi])ment consists of a f-cu. yd. gasoline shovel, an 8-ton gasoline locomotive, ten 8-yd. rocker dump cars, and two flat cars. Thirty-])ound rail and o6-in. track grade is used, with a maximum of 2% grade. Photo No. 32 shows the shovel at work during the prepara- tion of the pit. Tlie clay storage ])lant was designed with the object of .securing a thorough mixing of the clay as received from the pit, and to remove as much water as possible before sliipping. The clay is crushed to 2^ in. in a 21 by 42 in. single-roll crusher. The crusher discharge is carried by an IS-in. belt conveyor to llie top of tlie storage building, where it is spread in a lliin layer over the surface of llie bin by a self-propelled, self-reversing 1rii)])er. Drying by the hot summer air sweej)ing tlirough the building is very etfective. A concrete reclaiming tunnel under the floor of the storage building is equipped with hand-operated gates to I CLAY RESOURCES AND CERAMIC INDUSTRY 151 dischar^^e the clay to an 18-in. belt conveyor, which carries it to a cross- tunnel at one end of the building, where the clay is delivered to an inclined-belt conveyor, 18 in. wide, running up to the top of the three oO-ton storage bins in the mill building. From the end bin the clay can be drawn directly into railroad cars on the spur track. PVoni either or all of the bins, the clay can be fed by apron feeders to a chute leading to a five-roller low-side Raymond mill. The ])ulverized clay is blown to a cyclone collector in the toj) of the mill building, and is delivered to any one of three -lO-ton bins, which are fitted with three sacking spouts each. The sacked clay is stored in the building while awaiting shipment. The pit is o])erated in the dry season between ]\Iay and December. The minimum operating force consists of the superintendent, two men on the shovel, two men on haulage, and two men to operate the plant. Two or three extra men may be required from time to time, and at the beginning of the season a track gang is employed for two weeks to prepare the track for the season's operation. Two men attend to shi|)|nng and pulverizing in the winter. The capacity of the i)lant, from pit to storage, is three 5-car trains ])er hour, or slightly over 540 tons ])er 8-hr. day. The maximum capacity of the storage building is 18,000 tons. The total annual capacity of the plant when operated as described is 50,000 tons. This could be increased without extra equipment by two-shift operation during the summer, with storage of pulverized clay, as well as crushed clay, at the beginning of winter. The storage and pulverizing plant require 192 hp., distributed as follows : Horsepower of Unit driving motor 21 by 42-in. single-roll crusher 40 18-in. conveyor, 366 ft. long 20 18-in. reclaiming conveyor, 265 ft. long 15 18-in. cross conveyor to mill building, 172 ft. long 15 Bin feeders 2 Raymond mill 60 Raymond mill fan 40 Total -- 192 ]\Iiscellaneous electric ])ower used on the property include a com- ))ressor for oi)erating rock drills, a inimji for draining the pit, and a lighting system. ^ Samples : At the time the pit w^as sampled, on August 13, 1925, the cut had not been carried to the bottom of the bed that corresponds to the No. 1-6 clay (sample No. 146, p. 303) on the pit of the Lincoln Clay Products Co. Two samples were taken, however, both of which overlie the No. 1-6 clay. In 1926, a sample of prepared clay was obtained from the company, and was tested under No. 280. No. 152 is a plastic clay lying in a 6-ft. bed beneath the capping. The test results are given on i)age 304. No. 153 (p. 299) is a less ]ilastic clay from a 3 to 4 ft. bed underlying No. 152. It is one of the clays included in the No. (sample No. 145, p. 291) clay of the Lincoln Clay Products Co. No. 280 is more re|)resentative of the material available during the normal operation of the pit. (See page 305.) GJaddhui, McBran and Company. Lincoln Plant. Athnll McP>ean, president; A. L. Gladding, vice president. General offices, 660 Market 152 DIVISION OP MINES AND MINING Street, San Francisco. Chas. Gladdino-, manager at Lincoln. The Lincoln ])lant of Gladding', McBean & Co. was established in 1875, and has operated continuously since that time. The compa):y was incor- porated in 1886, and has steadily expanded the scope oi its operations until at the present time it is the largest clay products manufacturing organization west of the Mississipi)i Valley. The company now owns three large plants, one at Lincoln, one at Glendale, Los Angeles County, and the third at Auburn, Washington. It has recently acquired control of the Los Angeles Pressed Brick Co., operating several large plants in southern California, and of the Denny-Renton Clay and Coal Co. of Seattle, Washington, operating two plants in Washington and one at Portland, Oregon. The Lincoln plant specializes on architectural terra cotta, fire brick, face brick, roofing tile, sewer pipe, chimney pipe, and garden pottery. A fine example of the use of architectural terra cotta manufactured at Photo No. 33. Clay pit of Gladding, McBean & Co., at Lincoln, Placer County. Lincoln is the new Russ Building in San Francisco. Photo No. 1 (frontispiece) is a view of this building. Many other important buildings on the Pacific Coast have been faced with terra cotta from one of the company's plants. Clay Deposit: The company owns 480 acres of clay land in Sec. 9 and 10 of T. 12 N., R. 6 E., M. D. M. The present working pit, shown in photo No. 33, is in the SE]- of Sec. 9. A section through the pit is as follows : Section Through Pit of Gladding, McBean & Co., at Lincoln. Sample Test data Thicknes.s, No. on page Character of material feet Lava: Andesite-agglomerale S 155 325 Pit sand : Iron-stained clay, sand and fine gravel 10 Sand and gravel, not usd 15 156 299 Fire-proofing clay, corresponding in quality and thick- ness to L. C. P. Co., No. 0, sample No. 145 7 157 304 Terra cotta clay, corresponding in quality and thick- ness to L. C. P. Co., No. 1-G, sample No. 146 15 CLAY RESOURCES AND CERAMIC INDUSTRY 153 Data Avere not availablo for definitely determining the correlation with the clay beds exposed on the properties to the north, but it seems ])robable that the fire-proofingr clay, sample No. 156, corresponds to the No. clay of the Lincoln Clay Products Co., sample No. 145, and that the terra cotta clay, sample No. 157, corresponds to the No. 1-6 clay, sample No. 146. The overlyinj? sand and j>ravel beds in the Gladdinj;, IMcBean pit would indicate that the lava cap was laid down on this area before these beds were eroded, whereas to the north most of the material overlyinji- the clay beds had been removed before the deposition of lava, and in some places the ujiper clay beds themselves had been partly encroached upon by erosion. However, the bed underlying the terra cotta clay is of similar material, which indicates either that the No. 7 and No. 8 clays of the Lincoln Clay Products Co. are absent here, or that the correlation does not hold. I\IiNiNG : The clay is mined by steam shovel in benches, as shown on photo No. 33. The pit is over 1100 ft. long:. Waste is carried to the dump, and clay to the plant, on an industrial railroad, with a steam locomotive and 5-ton dump cars. The production of clay is at the rate of approximately 500 tons per day during the dry season. Water that runs into the pit during the winter is pumped out at the beginning of each dry season, and little pumping is ordinarily required during the summer. Plant: The plant occupies a 25-acre tract, on the northern edge of the town of Lincoln, and nearly one mile southeast of the clay pit. An airplane view of the ])lant is shown on photo No. 34. In addition to clays from the local pit, clay and sand from lone, clay from Natoma, quartz from various sources, and grog are used in the body mixtures. In the design and operation of the plant, extreme care is used to ensure uniformit}^ of raw materials, and accuracy of body proportioning. I'pon being delivered to the plant, all materials are stock-piled sepa- rately in a covered shed. A 4-tou traveling crane reclaims the mate- rials and delivers them to one of nine small bins, which feed four dry pans, o])erated to grind through a 14-mesh screen. The ground mate- rials, still se])arate, are then elevated to storage bins. The body mix- tures are proportioned from these bins by means of disc feeders. The terra cotta body mixture contains approximately 50% terra cotta clay, 10.0% non-plastic clay, and 40.0% grog, by volume of minus 14-mesh material.^ The body mixture is prepared by double pugging, and the average water content of the wads is 26%. The wads are aged under damp burlap in cool rooms before being sent to the pressers, but the minimum aiding period is often only two or three hours. The pressing room has no unusual features. All of the terra cotta and garden pottery are shaped by hand pressing in plaster molds. Terra cotta, roofing tile and electrical conduit are dried in Carrier ejector humidity driers, which are designed to give accurate control over the four factors of time, temperature, humidity and velocity during drying. Tlie drying cycle in use at the time of visit on August 14, 1925, was as folloAvs: The drying atmosphere began with five hours at ]20° F. and 60% humidity was increased by steps to 212° and 50% ' Larkln. P. G., and Curry, E. R., Notes on Terra Cotta Body Shrinkage, Jour. Am. Cer. Soc. Vol. 8, p. 113, 1925. 154 DIVISION OP MINES AND MINING a CIS a a o o m 5 o o 5 6 bJ] O 'A o o K CLAY RESOURCES AND CERAMIC INDUSTRY 155 humidity, in a period of five hours, tlien Avas held at 212° F. Avith urailually decreasing; humidity for 12 hours, and the ware was finally drawn about one hour later. The averagre dryinjr cycle thus occupied 23 hours. Waste-heat tunnel driers are u.sed for firebrick and face brick. Eleven down-draft oil-fired muff}e kilns are in use for terra cotta firing. The body and glaze mature together at cone 4 (2000° P.), with a heating schedule of nearly four days. Four days are allowed for cooling, and three days for unloading and setting for the next burn, making the turn-over time 11 days. The average total linear shrinkage, on a plastic basis, is 6.9%. The body color is buff. Fire brick are made from a mixture of terra cotta clay (sample No. 157), ground fire brick grog, and fpiartz. The brick are shaped in a side-cut auger-machine. Three round down-draft kilns are usually in use for firing fire brick. The firing cycle occu])ies five to six days firing, and about an equal time cooling. The finishing temperature corresponds to cone 11 down, or 1285° C. Face brick are made from local materials, using all three of tlie materials mined in the company's pit, proportioned according to colors desired. Practically all the face brick produced in the ])lant is buff or cream color. An angei- machine shapes the brick, which are either end- or side-cut. They are fired to 2200" F. in round down-draft kilns, four of which are usually in use for this class of ware. The sewer ])i])e mixture contains 'fire-proofing clay' (sample No. 156), Tone sand and grog. Electrical conduit is made from the same mixture, with the addition of some Natonia clay (samjjje No. 212, j). 337). ^'P Twelve round doAvn-draft kilns are in service on these two classes of %^ ware, firing to a maximum tem]ierature of 1200" C. in about seven days, including the salt glazing period, then cooling for a nearly equal period. Roofing tile is made from a mixture of local materials and Natoma clay. Drain tile is made from a similar mixture. Both are shaped on an auger machine. The roofing tile is fired in a tunnel kiln, 363 feet long, with a 43 hour cycle to a maximum temperature of cone 3 (1145° F.). Studies made at the plant liave demonstrated a saving of 50% of the fuel consumption of a round down-draft kiln for this class of ware. In addition to the products already mentioned, flue lining is manu- factured. Four round down-draft kilns are in use for firing this product. All the firing is done with oil fuel, atomized by compressed air. A complete pyrometric control of all kilns ensures uniform firing condi- tions, and economy of fuel. Electric i)Ower is used throughout the plant. The plant contains an architectural and sculpturing dej)artment. a drafting department, and a ceramic laboratory. As in most plants specializing in architectural terra cotta, the staff of the ceramic labora- tory spend the greater i)art of their time developing glazes. About 600 men are emi)loyed in the plant, of Avhom a large proportion are on ])iece work. A summary of the kiln equi])ment and the ap])roxi- mate annual ca])acity of various classes of ware are given in the follow- ing table : /. 156 DIVISION OF MINES AND MINING Kiln Data and Approximate Annual Capacity of Gladding, McBean & Co. Plant at Lincoln. Firing' No. of Type of Max. temp., time, Annual Class of ware kilns kiln °F. days capacity Arcliitectural terra cotta- 11 Muffle d.d. 2000 3.75 12,000 tons Sewer pipe and conduit 12 Round d.d. 2190 7 20,000 tons Face brick 4 Round d.d. 2190 6 3,200 M Firebrick 2 Round d.d. 2370 6 1,600 M Chimney pipe 4 Round d.d. 1830 4 3,000 tons Drain tile Set with other ware Roofing tile 1 363 ft. tunnel 1975 43 hrs. 12,000 tons Garden pottery Occasional Lincoln Clay Products Co. M. J. Dillman, president, Lincoln. The Lincoln Clay Products Company has no manufacturing plant, and is exclusively engaged in the mining of clays. ^ The property is located two miles northwest of Lincoln, in "the N| of Sec. 4, T. 12 N., R. 6 E., M. D. M. It has been in operation for over thirty years. Photo No. 35. General view of the pit and plant of the Lincoln Clay Products Co., looking south from the top of the storage building of the Clay Corpora- tion of California. The Clay Corporation's offlce building is in the right foreground. The pit is w^orked in benches by a combination of a spiral a])proacli and an incline as shown in photos Nos. 35, 36 and 37. Benches are established on the bottom of each clay bed, or series of beds, that is to be mined separately. Gasoline locomotives are used to haul train- loads of stripping or clay from the upper beds and an incline hoist is used to remove the clay that is mined near the bottom of the pit. The pit is over 1200 feet long and 600 feet wide and the maximum depth is 60 feet. The clay is loosened by hand di'illing and blasting. A IJ cu. yd. gasoline shovel is used for loading clay from tlie thicker beds, and hand loading is used on the thinner beds. Five gasoline locomotives are in service. Two of these weigh three tons and the others weigh four, six, ' A clay-working plant i.s contemplated in the near future. CLAY RESOURCES AND CERAMIC INDUSTRY 157 Photo No. 36. Eastern end of pit of Lincoln Clay Products Co., near Lincoln. Samples No. 145 to 150 were taken from the pit. Photo No. 37. Western end of pit of Lincoln Clay Products Co. with clay grinding and storage plant of the Clay Corporation of California in the middle background. 158 DIVISION OF MINES AND MINING and eip:ht tons, respectively. A eentrifn^al ])um]) is used to remove run-otf water from the pit. A section tlirougli the pit follows : Average Sample Test data thicknes.s, No. on page Class of material feet Soil and gravel 1- 3 Lava 1- 6 145 291 -Xo. clay: Face brick body 8 146 303 No. 1-6 clay: Terra cotta body 1 .o 147 303 No. 7 clay : Tile, face brick, sewer pipe. High in iron. 12 148 336 No. 8 clay: Higher in iron than No. 7 6 149 298 No. 9 clav : Similar to No. 1-6 8 150 291 No. 10 clay: Similar to No. 9 22 A larjre storage shed, shoAvn in photo No. 35, provides storage of clay during the rainy season, allows for fluctuations in mining and shipping during the season, ensures a certain degree of mixing to mini- mize the effect of local variations in the quality of clay, and permits seasoning of clay for those customers who so desire. In the fall of 1918 a washing plant was built for the purpose of investigating the commercial pos.sibilities of marketing a waslied product. The clay was ground in a Graupner centrifugal mill, mixed with water, and settled in vats. The thickened slip was dipi)ed out by hand and sun-dried in shallow trays. The principal effect of tliis process was to eliminate a certain proportion of the sand that is present in the raw clay, thereby producing a finer grained clay that has a more uniform, but greater, shrinkage. On account of high freight rates on washed clay, compared to crude clay, and because of the fact that the washed clay did not ]iossess sufficient advantages in use, washing was discontinued after a brief period. In order to permit a study of the properties of the washed material, ]\Ir. Dillman kindly gave tlie writer a sack from the warehouse. This is sample No. 151, and the test results are given on page 303. An average of 12 men are employed. The annual output varies with market demands, but is usually in excess of 50,000 tons. The selling price of the clay, f. o. b. cars at the plant, averages $1.75 per ton. Miscellaneous Deposits. Previous publications^ by the State Mining Bureau have reported occurrences of clay at various points along or near the line of the Southern Pacific Railroad, from Alta to Gorge. The most i)romising of these were visited in August, 1925, and were in each case found to be derivatives of the andesitic tuff-breccias, rhyolite tuffs, or volcanic ashes that are remnants of the great Tertiary volcanic deposits that at one time completely covered the basement rocks of tlie west slope of Sierra Nevad? Mountains, before the more recent period of tilting and stream cutting that has resulted in the ])resent topography. Rock decomposition and alteration has i)rogre.ssed to a varying degree in many of these materials, with the result that in places there are exten- sive beds of fine-grained, white, greenish-white, or yellowish-white material having a certain degree of plasticity that are often mi.staken for useful clays. They are, however, of no value for ceramic ])urposes, on account of high drying and firing shrinkage, low cohesion in the partly-dried condition which results in serious cracking during drying, » Prel. Rept. No. 7, p. 67-73. CLAY RESOURCES AND CERAMIC INDUSTRY 159 low fusibility, and dii'ty yollnw or red firiii'old in the sixties, but later developeil into a eojjper pi-operty. In the lower workingis, sphalerite and pyrite increased in quantity and the Photo No. 38. Valley View Mine, Placer County. Portal of lower tunnel. (Sample No. 261 from glory hole that connects with the tunnel.) Photo No. 39. Valley View Mine, Placer County. Upper workings. (Sample No. 262 from bank to left (east) of center of view.) copper minerals decreased. There has been no production since 1918. The ore occurs in part in altered dikes which intrude the amphibolite schist country rock. In the upper workings, still accessible through a tunnel, a glory hole, and an open cut, the dike rock has been kaolinized. CLAY RESOURCES AND CERAMIC INDUSTRY 161 The degree of kaoliiii/fitioii and tlie percentage of iron vary eonsid- eral)ly in different i)arts oi' tlie exposures, but in places the material is well kaolinized, lias fair plasticity, and is comparatively free from iron. Photos No. .'58 and 8i) are views of the property. Three samples were taken. No. 2(il (p. o2S) was taken from an undci-ground cliamber that connects by a chute to the tunnel, the i)ortai of which is shown on photo No. 38. The sample represents a small kidney of kaolinized material, exposed over an area about 10 feet square, and at least 4 feet thick. A ])eculiarity of the sample is that while it is distinctly red-burning, it has a softening point of cone 28 (1615° C). No. 262 (p. 350) was taken from the open cut shown in photo No. 39, and is representative of the material from the bank to the left (east) of the center of view. Tliis material has little or no ceramic value. No. 263 (p. 292) is a sample of white kaolin from the same open cut. It occurs as small isolated pockets, some of which are clearly shown on the right-hand side of photo No 39 as white patches. The material is nearly wiiite- burning. has fair pla.sticity, and a high softening temperature (cone 32-33, about 1720° C). Unfortunately, thei'e is little indiccition that large bodies of equally good material will be found on the property. Bibl (Vallev View Mine) : Cal. State Min. Bur. Bull. 50, p. 174. Kept. XV, pp. 327-330; XXIII, pp. 246-247 and 286. RIVERSIDE COUNTY. General Features. Riverside County lies in the southern portion of the state. It is bounded on the north by San Bernardino County, on the east by the state of Arizona, on the south by Imperial and San Diego counties, and on the west by Orange County. The county has an area of 7420 square miles and a population of 60,297 (1920 census). It is the fourth county in size and the seventh in regard to the total value of mineral output (1925). The surface of Kiverside County, like that of much of southeastern California, is characterized by bare mountain ranges, separated by nearly-level arid belts of varying width. The minor ranges of moun- tains rise abruptly from the desert plains, having the appearance of being the summits of larger ranges whose bases are buried beneath the loose deposits of the desert. The San Bernardino and San Jacinto mountains are the most prominent ranges, the peaks of which rise to more than 10,000 feet above sea level. On the western edge of the county, and sei)arating it from Orange County, is the Santa Ana Range. Geology. A detailed study of the geology of Riverside County has not yet been made. In the desert areas of the eastern portion of the county, the principal formations, besides Quaternary gravels, are pre-Cambrian and Paleozoic metamorphics ; some Tertiary sediments, mostly Pliocene ; and various plutonic and volcanic rocks. In the western portion of the county, near Orange County, are extensive areas of Triassic, Upper Cretaceous, Eocene and Miocene age.^ » Smith, J. p., The geologic formations of California : State Min. Bur. Bull. 72 and Geological Map. See also for bibliography ui- to date of issue in 1916. 11 — 54979 162 DIVISION OF MINES AND MINING The mineral resources of the county incIivJo V^rick, cement, clay, coal, copper, feldspar, gems, gold, gypsum, iron, lead, limestone, manganese, magnesite, marble, mineral paint, mineral water, salt, soapstone, silver, miscellaneous stone, and tin. In 11)25, seventeen dift'erent minerals were commercially produced, the most important being, in the order of their production, cement, miscellaneous stone, brick and hollow building tile, pottery clay, silica (quartz), granite, feldspar, and lead. Clay Resources. The Alberhill-Corona district in western Riverside County is one of the three most important clay producing areas in the state. The clay deposits extend in a belt along the Temescal Valley for fifteen miles from Elsinore on the southeast to Corona on the northwest. The clays were laid down in Eocene time, when the Temescal Valley was an arm of the sea opening northward into the valley of western San Bernardino County and extending southerly to Temecula. The width of the basin is from one to two miles, and the depth in places is over 600 feet. A property map of the district is given on plate X. The general character of the deposits is well described in the follow- ing excerpts from an article by the late J. H. Hill,^ then president of the Alberhill Coal and Clay Company, the largest producer in the district : "At the Alberhill pits, the clays present a wide diversity of color, character, and degree of consolidation. An extraordinary variety is found, including siliceous fire- clays, ball clays, plastic white- and buff-ljurning clays, highly aluminous and very refractory clays, numerous red-burning clays, and an extensive bed of material from which a china clay is obtained by v^ashing. A bed of lignite coal ranging from two to eleven feet in thickness occurs conformably with the clay strata, and adjacent to this the best fireclays are found. The strata are regular and persistent, and dip to the southwest with an average value of 10 degrees, with local variations due to an undulatory or wavy folding. "Minor local disturbances appear to have prevailed at Intervals during deposition of these clays, and coarse sandy beds are interspersed with fine-grained plastic clays. In these sandy beds, the coarse silica sand is often intermixed in a sporadic and irregular fa.shion with the accompanying clay substance. Mottled clays apparently due to simultaneous deposition of different kinds of sediments derived from separate sources are also found. The beds in general seem to indicate that long quiescent periods during which fine-grained clays were laid down were preceded and followed by stormy periods when frequent freshets or strong tidal currents brought in coarse silica sand and granite debris from surrounding highlands. The top soils of the region consist of debris of disintegrated granite, and vary from, a few inches to many feet in thickness. "Owing to the masking of the surface by the layer of disintegrated granite material, the total extent of the Alberhill deposit has not yet been fully determined. However, a large number of bore holes have been put down on widely separated portions of the property, and in every case clays of good quality were found to the full extent of the hole in depth. From this and other evidence, it seems quite probable that the entire mass of the small moimtain. above the valley floor and for an unknown depth, is clay. A few isolated occurrences of shale have been noted. Exploration to date has been sufficient to indicate beyond doubt that the quantity of readily available clay is so vast as to be inexhaustible for all practical purposes. * * * The hill comprising the deposit is about two and one-quarter miles long and one mile in width, with an average elevation of 16S0 feet. The main line tracks of the railway * • * are at an elevation of 1277 feet. * * * The present pits are all somewhat above the level of the railroad tracks." While Mr. Hill's estimate of clay reserves may have been somewhat optimistic, in the light of more recent work which indicates that the deposits lie in the form of a synclinal trough again.st the eroded surface of the mountain ranges on each side of the valley, it is substantially true that the supply of readily available clay is sufficient to last for many years, even at increased rates of production. Considering the district as a whole, the principal deposits lie on the eastern side of the * Clay deposits of the Alberhill Coal and Clay Company : State Mineralogist's Report XIX. pp. 185-210, 1923. CLAY RESOURCES AND CERAMIC INDUSTRY 163 [it deposits in the floor of the vallev and toward the western " ' * '^ "■ '• "•- and Uey e of )OUt ittle ■rial tion eific )elt, 1 or jecn oad low / A ^KM.^A. t Vyj. wC4,XJ. ine. ate uls dts mt nts the s a ed. •er, 3p- oal x^ed to work the coal beds that occur here, and for 13 years previous to 1895 the property was developed solely as a coal mine. The production 162 DIVISION OF MINES AND MINING The mineral resources of the county inelu'Je V^rick, cement, clay, coal, copper, feldspar, gems, gold, gypsum, iron, lead, limestone, manganese, magnesite, marble, mineral paint, mineral water, salt, .s()ai)stone, silver, miscellaneous stone, and tin. In l!)2o, seventeen ditferent minerals were commercially produced, the most important being, in the order of their production, cement, miscellaneous stone, brick and hollow building tile, pottery clay, silica (quartz), granite, feldspar, and lead. Clay Resources. The Alberhill-Corona district in western Riverside County is one of the three most important cla}^ producing areas in the state. The clay deposits extend in a belt along the Temescal Valley for fifteen miles from Elsinore on the southea.st to Corona on the northwest. The clays were laid down in Eocene time, when the Temescal Valley was an arm of the sea opening northward into the valley of western San Bernardino County and extending southerly to Temecula. The width of the basin is from one to two miles, and the depth in places is over 600 feet. A property map of the district is given on plate X. The general character of the deposits is well described in the follow- ing exceri)ts from an article by the late J. H. Hill,^ then president of the Alberhill Coal and Clay Company, the largest producer in the district : "At the Alberhill pits, the clays present a wide diversity of color, character, and degree of consolidation. An extraordinary variety is found, including siliceous fire- clays, ball clays, plastic white- and buff-burning clays, highly aluminous and very refractory clays, numerous red-burning clays, and an extensive bed of material from which a china clay is obtained by washing. A bed of lignite coal ranging from two to eleven feet in thickness occurs conformably with the clay strata, and adjacent to this the best fireclays are found. The strata are regular and persistent, and dip to the southwest with an average value of 10 degrees, with local variations due to an undulatory or wavy folding. "Minor local disturbances appear to have prevailed at intervals during deposition of these clays, and coarse sandy beds are interspersed with fine-grained plastic clays. In these sandy beds, the coarse silica sand is often intermixed in a sporadic and irregular fashion with the accompanying clay substance. Mottled clays apparently due to simultaneous deposition of different kinds of sediments derived from separate sources are also found. The beds in general seem to indicate that long quiescent periods during which fine-grained clays were laid down were preceded and followed by stormy periods when frequent freshets or strong tidal currents brought in coarse silica sand and granite debris from surrounding highlands. The top soils of the region consist of debris of disintegrated granite, and vary from a few inches to many feet in thickness. v "Owing to the masking of the surface by the layer of disintegrated granite material, the total extent of the Alberhill deposit has not yet been fully determined. However, a large number of bore holes have been put down on widely separated ])ortions of the property, and in every case clays of good quality were found to the full extent of the hole in depth. From this and other evidence, it seems quite probable that the entire mass of the small mountain, above the valley floor and for an unknown depth, is clay. A few isolated occurrences of shale have been noted. Exploration to date has been sufficient to indicate beyond doubt that the quantity of readily available clay is so vast as to be inexhaustible for all practical purposes. • * * The hill comprising the deposit is about two and one-quarter miles long and one mile in width, with an average elevation of 16S0 feet. The main line tracks of the railway • * * are at an elevation of 1277 feet. * * * xhe present pits are all somewhat above the level of the railroad tracks." While Mr. Hill's estimate of clay reserves may have been somewhat optimistic, in the light of more recent work which indicates that the deposits lie in the form of a synclinal trough against the eroded surface of the mountain ranges on each side of the valley, it is substantially true that the supply of readily available clay is sufficient to last for many years, even at increased rates of production. Considering the district as a whole, the principal deposits lie on the eastern side of the ' Clav deposits of the Alberhill Coal and Clay Company : State Mineralogist's Report XIX, pp. 185-210, 1923. ri.ATK X, JTupcily riiiii] uf AUji.iliiil-Curiiiiu. diatiiL-t. Riverside Ouiiily. (By courtesy of Uubt. LiiUuii.) OV'J — facing page 1C2 162 DWISION OP MINES AND MINING The mineral resources of the county inclu'le brick, cement, c copper, feldsDar, irems. Qokl. t>-vi)siini imn it.u,i i;,.ioc.+r>.,.^ -^- magnesit miscellan were con of their building Clay Resc The A the three deposits from Els were laid of the sec County a is from c property The ge ing exeer the Albe district : "At the degree of ( clays, ball refractory which a ch to eleven f. this the be the southw undulatory "Minor 1 of these elf In these sj irregular f; due to simi sources art periods dur by stormy silica sand region con; many feet "Owing material, tl However, s portions of full extent probable th an unknow Exploratior readily ava * * * "J" one mile in the railwaj are all som While : optimistic deposits 1 of the m( true that many yeg district af ' Clay deposits of the Alberhill Coal and Clay Company : State Mineralogist's Report XIX, pp. 185-210, 1923. CLAY RESOURCES AND CERAMIC INDUSTRY 163 valley, but (loi)osits in the floor of the valley and toward the western side are of ini|)or1an('(' at a nninber of plaees. Foidinji', faultin^^, and erratic deposition aic most proiionneed on tiie eastei'n side of the valley ill the vicinity of Alhcrhili. The Emsco de])osit, on the same side of the valley, at an elevation of about 200 feet above the Moor, and abont six miles to the nortlnve.st of All)erliill (see maj), plate X), shows little evidence of structural complexity, and the character of the material ill the different beds is uniform over a lar.ue area. This same condition (u-evails at most of the west side pits, except the IMcKni^ht jiit (Pacific (May Products Company), near the northern limit of the clay belt, west of Corona, where the structure is more comi)lex. 'Slant of the pi'omisin^' clay land in the district has been purchased or leased by various companies. The ac(|uisition of ])roperty has been particularly active since 11)24. when it became apparent that a railroad connection was to be made from Alberhill to Corona. This line is now 6ectien Pas.'fs In Rear Of Mam P»t Pit \ \ rautt R.4. Bone Htd. m»tH€ Lignite Coat Pink = ~|m»ttK I'l.ATic XI. ] )iaf;rammjiti(; section of .strata at Alberhill, in a general west-east line. (From Slate Mineralogist's Report XIX, p. 1 90, 1923.) completed, and has not only resulted in a decrease in the freight rate from Alberhill to Los Angeles, but has eliminated long truck hauls throughout the district. Outside of the Alberhill-Corona district, few commercial clay deposits have been found in the county. Common clays are sufficiently abundant near the more populous i)arts of the county to serve all re((uirements for the manufacture of common brick. The desert portions of the county have not been thoroughly prospected for clays, and there is a chance that in the future a few interesting deposits will be discovered. Alberhill Coal and Clay Company. Chas. Biddle, general manager, Alberhill, California. This com])any owns nearly 2000 acres of prop- erty, parts of which are leased to other companies. The principal holdings are shown on plate X. The company was originally organized to work the coal beds that occur here, and for 13 years previous to 1895 the property was developed solely as a coal mine. The production 164 DIVISION OP MINES AND MININO CLAY RESOURCES AND CERAMIC INDUSTRY 165 of clay started in 1S95 and it has been continuous since. The company lias no clay-working plants, but sells clays to many manufacturers throughout California, particularly in the Los Angeles district. More than thirty varieties of clav are mined and marketed. Photo No. 41. Alberhill Coal & Clay Company. Cut connecting main and west pits. 'Die AlVierhill plant of Gladding, McBean & Company (formerly Los Angeles Pressed Brick Company) is in the background. Riverside County. (From State Mineralogist's Report XIX, p. 189, 1923.) Photo No. 42. Alberhill Coal & Clay Company. One of the loading trestles. Riverside County. (From State Mineralogist's Report XIX, p. 191, 1923.) The operations of the company were described by the late J. H. Hill in an earlier report^ by the Bureau. For the sake of completeness, this article is freely used in the present report, with some additional 'Hill, J. H., op. cit. 166 DIVISION OF MINES AND MINING ■>-> m m 3 3 H C " CD M 0) ^ bn ^ T-1 (X < IS . O bo o rt c o > w ti-i C cS ^_> '^ o 5 ^ >> ■i-l >■ c O O 3 r- • O 5 So ^ a> ;- 5 ^ 0; j^ > ■* - J3 o X |1< CLAY RESOURCES AND CERAMIC INDUSTRY 167 Photo No 44. AlberhiU Coal & Clay Company. Riverside County. An exposure of lignite coal. The clay stratum directly below the coal is SH-4 (sample No. 273) ; that directly above is SH-o (sample No. 28). (From State Mineralogist's Report XIX, p. 200, 1923.) 168 DIVISION OP MINES AND MINING details on recent developments. The reader is referred to Mr. Hill's article for further details not covered herein. Geological Section. An idealized geoloj?ical section of the Alberhill pits, as i)repared by Mr. Hill, is shown on plate XL This sketch is broadly generalized, and may be considered as a composite of the various beds, in their normal stratigraphic sequence. There is perhaps no locality on the property Avhere the series is complete, as some of the beds are thicker in one i)lace than in another, and other beds are entirely lacking in places. Burchfiel ' gives the following cross-section as being fairly representative : Kind of strata. Soil Yellow top clay Yellow main tunnel clay No. of feet 3 20 6 34 6 4 4 12 Main tunnel clay Coal Bone clay No. W-105 Clay between bone and blue clays Select west blue clay West tunnel blue clay Shale Plate XII. Handling and storage of clay bv the "glory-hole" method. (From State Mineralogist's Report XIX, p. 193, 1923.) Photos No. 40, 41, 43 and 44, all from Mr. Hill's article, illustrate various topographic and geologic features on the Alberhill property. Mining Methods. Wherever possible, the clays are mined by open- pit methods. The clays stand well in vertical banks up to 40 or 50 feet in height. As operations are scattered, all loading is by hand. Glory-hole mining is used at various places. Underground mining by room-and-pillar methods is used where the overburden is thick, or where it is desired to mine special varieties of clay without removing overlying beds. In 1926, extensive underground operations w^ere started for mining the 'hill blue' clay, and it is expected that most of the production of this important variety will be obtained from these workings in the future, rather than from open pits. Plate XII, by Hill, illustrates the general method of glory-hole min- ing. Photos No. 40, 41, 43 and 44 illustrate various features of the 'Burchfiel, B. M., Refractorv clavs of the Alberhill, California, Deposits: Jour. Amer. Cer. Soc, Vol. 6, p. 1167, 1923. CLAY RESOURCES AND CERAMIC INDUSTRY 169 iiiininfr ojioratinns, and photo No. 42 shows one of the loading trestles and bins Tor doliveriny tlic clay to railroad cars. At many of the pits, AvheelbarroAvs are used to deliver the clay to a loading chute, from which it is delivered by gravity into trucks for hanling to the railroad. At otlier pits, small mine cars are loaded by iiand, and are trammed by horses to the dumping points. In tlie glor\' holes and underground workings, mine cars are used. These are trammed by hand, with liorses, or by electric trolle.y locomotives, depend- ing upon tlie length of haul and average daily ]~»rodiiction nf the woi'kiiig. Tlie total ])rodiiction of clay from the company's property is about 15,000 tons annually, and prices (f.o.b. Alberhill) range from $1.25 ])er ton for the ])oorer varieties, such as yellow stri])ping, to $5.50 ])er ton for some of the selected varieties of white-burning clay. .Most of the varieties sell for $2 to $3.50 per ton. The clays enter into the manufacture of a great diversity of products, ranging from china to lieavy structural wares. The diversity of clays makes it possible to produce many specialized wares. This is particularly true of the refractory and face-brick branches of the clay industry. Samples. Twenty-six samples from this property were tested. For convenience of reference, these are grouped below according to the clay classification adopted in this rejiort, which is fully described in Chapter IV. Sample Record, Alberhill Coal and Clay Company. Clay Clay Fircfl class sample Page Cone color number number reference Local nomenclature fusion White 1 11 257* E-101 china clay 28-29 12 257* E-102 china clay 26-27 2 15 264* Select main tunnel 30-31 28 264* SH-3 30 29 264*t Main tunnel (M.T.) 30-31 3 273 273*t SH-4 (ball clay) 34 Bull 5 17 277*t W-105 bone clay 34 23 277* West blue 29 6 9 287* Hill blue (1925) 29 14 287 A-clay 31 27 287* No. 10 30-31 272 292 Hill blue, M.T. (1926) 29 7 13 296 Extra select M.T. 29-30 271 301 Hill l)lup, lower tunnel 31-32 274 302 Hill l)lue, upper tunnel 30 9 19 311 Diamonrl 23 2.5 .•!ll*t West tunnel blue 16 10 16 314*t Select west blue 18 Red 12 8 321 Red clay No. 2 19-20 18 321 Clark tunnel mottled 19 24 321 West tunnel mottled 18-19 26 321* West yellow not det. 13 7 328* Pink mottled 17 14 10 334* Hill blue green 14-15 21 334 Sagger 23 22 335 Yellow Owl cut 17 * The properties of the.se A-arieties are also given by Hill, op. cit.. E-p2 varieties are discu.ssed under "D.C. clay." t The properties of these varieties are also "given by Burchfiel, o;?. The E-101 and cit. Emsco Clay Co. {Havringion Pit). Location: The Emsco Clay Company of Los Angeles has leased from John Harrington the Har- rington clay pit, in Sec. 35, T. 4 S., R. 6 W., in the Temescal Canon, 10.5 miles by road southeast of the center of Corona, and 7 miles by road southeast of a loading siding on the southeastern side of Corona. 170 DIVISION OF MINES AND MINING o rv O o 5 03 m . «^ c £>. o rt U o ■D'O £5 .i. c .c 53 a o.S U be S'rS H c m .^ 4) o So a ft bBo! i-j " fc. c« o- c 6 -bo o C Li o- o o m s o o f-> o K CLAY RESOURCES AND CERAMIC INDUSTRY 171 Tho uowly compU'tetl raili'oad connection I'l'oui Alberhill to Corona passes Avithin It] miles of the property. The property under lease comprises 80 acres, and lies on the east side of the valley, 300 feet above its floor. It lias been operated intennittcittly for many years, formerly by the now extinct Indei)en(lent Sewer Pipe Co., wiio hauled the clay in wagons to the Chase railroad spur, south of Corona, for shipment to Tropico. Tt was later under lease to the Alberhill Coal and Clay Co.. who did not actively develop the i)i-o])orty, as the com- bined transportation costs to Los Aiien cuts extending along the east side of the i)resent Avorkings, and running up the hill with the clay which dii)s about 10° to 15° toward the south. There are several tunnels from these pits. To the west, about one-quarter mile from the active pit, it is extensive open cut and chambor workings from Avhich pink mottled and white plastic clay has recently been mined. Three to four cars ])er day are being mined and three men are employed ;i1 the pit, exclusive of truck drivers. Gladding, McBean and Companij. Office of Southern Division at 621 S. Hope Street, Los Angeles. Through its merger with the Los Angeles Pressed Brick Conijiany in 1926, this company now controls important clay lands and a clay working plant at Alberhill, in addition to the Temescal Tract already owned by the company prior to the merger. Alberhill Clay Property. The clay property in which the plant is located totals 520 acres, in Sees. 21 and 22, T. 5 S., R. 5 W., as shown on plate X by legends L. A. P. B. Co. and L. A. P. Co. This property adjoins the Alberhill Coal and Clay Company's property on the east. 172 DIVISION OP MINES AND MINING The main tunnel pit adjoins the Alberhill company's main tunnel pit, and is shown on photos No. 40 and 47. Clay from this pit is loaded by hand into side-dump mine cars, and hauled by electric trolley locomo- tives across a trestle to the plant on the west side of the railroad, or to railroad bins for shipment to the Los Anjreles plants of the company. The priiicij^al clay obtained from the pit is main tunnel fireclaj^ which is used in the manufacture of fii'e brick. Photo No. 46. Loading chute, Emsco Clay Co. (Harrington pit). Riverside County. About a half mile southwest of the main pit is the Sloan pit, from which a number of varieties of clay are produced. A representative cross-section of this pit is given by BurchfieP as follows: No. of feet 40 30 6 4 50 Strata Overburden and j^ellow top clay Sloan clay Sloan No. 5 clay Sloan bone clay (1923) Red clay ' Op. cit., p. 1173. CLAY RESOURCES AND CERAMIC INDUSTRY 17o This j)it "vvas still an inipoctanl prnduooi- when tlio ])i'()i)orty was visited by the author in l!)^.') and l!)2(). The clay was l)('in'ed in the i'ollowinji' table accordin.<>' to the cla\- classilication adopted in this report, which is fully described in Cluii)ter IV. Sample Record, Gladding, McBean Co., Alberhill Pits. Clay Clay Firefl class sample Page Cone color miiiiber number reference Local nomenclature fusion White 1 91 260 Main tunnel sand .•!0-31 103 260* Sloan bone 3r> 2 90 265 Main tunnel fireclay 31 93 265 Select main tunnel 30-31 3 96 272 No. 10 32 98 272 Bone (W-105?) 35 Huff 5 104 279* No. 5 Sloan 34-35 6 92 289 Yellow main tunnel 28 97 290 Smooth bunker 31 102 290 Sloan sand 29 7 101 298 Sloan white 30 9 94 311 West blue 17 95 311 Select west blue 18 99 312 Tile 26-27 Red 12 100 323 Yellow stripping 14 plu 105 324 Sloan red 18 plu * Bur(>hfiel, op. cit.. p. 1174. gives data on No. 5 Sloan, and states that the Sloan bone is "iJiactically identically the same as the bone clay No. W-105." He also gives data for the yellow top clay from the Sloan pit. The total clay production from all of the pits on the company's Alberhill property is about 500 tons per day, much of which is .shii)])ed to the company's plants in Los Angeles. Alberhill Plant. The principal products of the Alberhill ])lant are fire brick and other fireclay refractories, face brick, and hollow tile. Hand-molded roofing tile is also made. The face brick, fire brick, and hollow tile are made by the stift'-mud process, after preparing the clays in dry pans. Most grades of fire brick are repressed. Waste-heat tunnel driers are used. All ware is fired in round down-draft kilns, of which there are twelve, of various sizes from 32 to 38 feet in diameter. The plant is well arranged, and well equipped to handle all materials in so far as is feasible. A well-equipped field laboratory is maintained for the study of raw materials and for research on the technical i)roblems arising in the l)lant. Temescal Tract. This property, totaling 173 acres, is west of the Emsco Clay Company's property, 0.4 mile east of the Corona-Elsinore highway, and 25-30 feet above the floor of the valley. Development. The principal pit i.s 800 feet long, 500 feet wide and a maximum of 150 feet high. Red, pink-mottled and blue plastic clays have been mined. The varieties were apparently badly mixed, and the present exposures in the face of the bank do not offer much encourage- ment for expecting a satisfactory supply of uniform material. Some 174 DIVISION OP MINES AND MINING development work is being done in a tunnel at an elevation about 100 feet higher than the pit and it is stated that good clays were found underlying the Emsco clays. At the times of visit, in 1925 and 11)26, the ])it was idh', but was being held in reserve for the future. /. D. Hoff, of Elsinore, owns a cla}' property in Sec. 22, T. 5 S., R. 5 W., on which some prospecting has been done, by core-drilling and Photo No. 4 7. Gladding, McBean and Company (formerly Los Angeles Pressed Brick Company), .A.lberhill, Riverside County. Main tunnel pit leased from the Alberhill Coal & Clay Company. (See also photos No. 40 and 41.) test-pitting. A number of samples were sent to the Stanford labora- tory by Mr. Hoff, but none of these were large enough to test. The general appearance of some of the samples is the same as that of certain clays from other properties in the district. Mr. Hoff expects to build a clay-working plant near Alberhill in the near future. Los Angeles Brick Co. Gustave Larsen, director in charge of opera- tions ; Harvey Gardner, plant superintendent at Alberhill. Main office, 1078 Mission Road, Los Angeles. This company acc^uired the holdings CLAY RESOURCES AND CERAMIC INDUSTRY 175 of the former California Clay Maiiiifaetnrint: Company in the Alberhill district, and built a plant at AlborJiill in ^\)27) for tlie manufacture of face brick, fire brick, roofino- file, floor tile, and hollow tile. The manu- facture of other products is contemplated by the company. The pi-oi)erty at Alberhill consists of the SEj and the E^ SW^ Sec. 21, T. 5 S!, R. 5 W., S. B. M., and other nearby property totalinj? 720 acres. This lies to the west of the principal holdings of the Los Angeles Pressed Brick Co. Most of the clays that are being mined at ]iresent are from the western limb of the synclinal trough in which the clays of the district lie. The clays include most of the varieties that typify the Alberhill district, and occur in the same irregular fashion, without notable continuity of individual strata. There is apparently, however, a more extensive dei)osit of high-grade bone clay on this property than in any otlier known locality in California. Clay Deposits: A numbei- of ])its have been oi)ened on the property, but at the time of visit, in July, 1925, and September, 1926, it was not ])ossible with the data at the writer's disjjosal to definitely establish the stratigrai)hic correlations between the various pits, nor between the nearby pits of other operators. A number of samples were taken on botli occasions. No. 74 to 87, inclusive, were taken in 1925, and No. 229 to 2:52 inclusive, in 1926. Vertical sections through the "East," "West," and "Main" pits are given in the following tables. Photo No. 52 shows the East pit as it ap])eared in September, 1926. Sample No. 230 Page No. 300 Vertical Section, East Pit, Los Angeles Brick Co. (From top to bottom.) Local name Thioknoss. or number Principal uses fi'f t Stripping Sometimes for face brick 0-10 Pink-mottled Face brick, tile ir)-20 No. 1 red Face brick, tile 10 No. 9 Fire brick IT) Sample Page No. No. 81 289 76 28S 77 27S 711 278 so 297 7S 2S8 Vertical Section, West Pit, Los Angeles Brick Co. (From top to Ixittom.) Local name Thickne.ss. or number Principal uses feet Tile clay Hollow tile, roofing tile 6 No. 2.') Fire brick and pottery 10 No. 23 Fire brick and pottery 10 No. 20 Pressed brick, fire brick 20 Fireclay Firebrick 10 Plasti<- pink and yellow Fire brick and i)ottery ? No. lO' Fire brick 20 Vertical Section, Main Pit, Los Angeles Brick Co. (From top to bottom.) Sample Page Local name Thickness, No. No. or number Principal uses feet S.'') 298 Pink mottled Fire brick, sewer pipe, tile, pottery — Up to 30 ft. 86 279 No. 26 bone Fire brick 6 85 298 Pink mottled See above Up to 10 ft. 83 297 Red clav Hollow tile, roofing tile 12-15 84 289 P. M. fireclay Fire brick 10-20 A number of samples were taken from undeveloped or partially develoi)ed beds. For convenience, these are given in the following table : 176 DIVISIOX OF MINES AND MINING Miscellaneous Samples. Los Angeles Brick Co. Thick- Sample Page Local name Name of pit from wliicli ness. No. No. or number sample was taken Principal uses feet 74 278 West bone West bone pit Fire brick 4- 6 75 335 Red No. 2 West bone, underlying Tiie and face No. 7 1 brick ? 87 279 Smooth bone 100 yd. E. of main pit, overlving No. 86 Fire brick 15 232 281 Smooth bone ? ' Fire brick 6 231 281 High-alumina bone ? Fire brick 4 82 315 Clay shale Blue pit Tile and f a c e brick 10-20 229 300 No. 7 No. 7 pit Fire brick 34 Note. — Samples No. 231 and 232 were supplied by Mr. Gardiner in Septeml)er, 192(;. Name of pit from which sample was taken was not given. The areal extent of these various clays can not be definitely deter- mined in the absence of core-drilling- data. Enough evidence is at hand, however, to warrant the statement that many of the beds are practically continuous over areas in excess of -300 acres, although it is doubtful if the clay in an individual stratum will be uniform in quality over such an area. Mining: The clay is mined from the various open pits by hand methods and is transported to the plant by auto trucks. Plant : Face brick, both plain and ruffled, is the principal product of the Alberhill ])lant. Fire brick is being made in increasing amounts, and a special high-alumina fire brick is being manufactured from the bone clays that occur on the property. Photos No. 48 to 51 show various views of the plant, and photo No. 52 is a view of the east pit. The clays as they are received from the pits are ground in dry pans, and elevated to separate steel bins for each variety of clay. From the bins, disc feeders are used to feed an augur machine, which is equipped with an automatic cutter. Repressing is applied on ware that requires it. A 32-tunnel waste-heat drier operates on a 48-hour cycle. Firing is done in four 32-ft. and eight 34-ft. round down-draft kilns, fired with air-atomized oil. Buff and cream face brick and all firebrick are fired to cone 11, and red face brick are fired to cone 10. Four daj's is allowed for firing, four days for cooling, three days for drawing, and two days for setting. Each Iciln is therefore fired about twice a month. One hundred and twenty-five men are employed in the plant, and twenty in the pits. Pacific Clay Products Company. Robt. Linton, general manager, 1151 S. Broadway Street, Los Angeles. This company-, which has a number of manufacturing plants in Los Angeles County, owns and operates several clay proi)erties in Riverside County. The location of the properties in the Alberhill-Corona district is shown on plate X, page 162. Douglas Pit. This is an 80-acre tract consisting of the Ni of NE^ Sec. 22, T. 5 S., R. 5 W., S. B. M., adjoining the active pits of the Alberhill Coal and Clay Co. on the north. A view of the pit is shown in photo No. 53. The pit is mined by hand methods, using shovel and wheelbarrow to deliver the clay to small loading chutes for loading the trucks which haul it to the railroad bins. 177 111(1 llie 'scribed "om top 11 uction. r^. .JjC, driers, Thickness of bed, feet 5 4 7 50-70 176 DIVISION OF MINES AND MINING Miscellaneous Samples. Los Angeles Brick Co. Thick - Sample Pago Local name Namo of pit from whicli ne.ss. No. No. or number sample was taken Principal uses feet 74 278 West bone West bone iiit Fire brick 4- 6 75 335 Red No. 2 West bone, underlying Tiie and face No. 7 1 brick ? 87 279 Smooth bone 100 yd. E. of main pit, overlying No. 86 Fire brick 15 232 281 Smooth bone ? Fire brick 6 231 281 High-alumina bone ? Fire brick 4 82 315 Clay shale Plue pit Tile and face brick 10-20 229 300 No. 7 No. 7 pit Fire l)rick 34 Note. — Samples No. 231 and 232 were supplied by Mr. Gardiner in September, 192(;. Name of pit from which .sample was taken was not given. The ureal extent of these various elays can not be definitely deter- mined in the absence of core-drilling data. Enough evidence is at hand, however, to warrant the statement that many of the beds are practically continuous over areas in excess of 300 acres, although it is doubtful if the clay in an individual stratum -will be uniform in quality over such an area. Mining : The clay is mined from the various open pits by hand methods and is transported to the plant b}^ auto trucks. Plant .- Face brick, both plain and ruffled, is the principal product of the Alberhill ]ilant. Fire brick is being made in increasing amounts, and a special high-alumina fire briclv is being manufactured from the bone clays that occur on the property. Photos No. 48 to 51 show various views of the plant, and photo No. 52 is a view of the east pit. The clays as they are received from the pits are ground in dry pans, and elevated to separate steel bins for each variety of clay. From the bins, disc feeders are used to feed an augur machine, which is equipped with an automatic cutter. Repressing is applied on ware that requires it. A 32-tunnel waste-heat drier operates on a 48-hour cycle. Firing is done in four 32-ft. and eight 34-ft. round down-draft kilns, fired with air-atomized oil. Buft" and cream face brick and all firebrick are fired to cone 11, and red face brick are tired to cone 10. Four days is allowed for firing, four daj^s for cooling, three days for drawing, and two days for setting. Each kiln is therefore fired about twice a month. One hundred and twenty-five men are employed in the plant, and twenty in the pits. Pacific Clay Products Coinpany. Robt. Linton, general manager, 1151 S. Broadway Street, Los Angeles. This company, which has a number of manufacturing plants in Los Angeles County, owns and operates several clay properties in Riverside County. The location of the properties in the Alberhill-Corona district is shown on plate X, page 162. Douglas Pit. This is an 80-acre tract consisting of the N^ of NE^ Sec. 22, T. 5 S., R. 5 W., S. B. M., adjoining the active pits of the Alberhill Coal and Clay Co. on the north. A view of the pit is shown in photo No. 53. The pit is mined by hand methods, using shovel and wheelbarrow to deliver the clay to small loading chutes for loading the trucks which haul it to the railroad bins. al view of AlbeihiU plant, L<.s Angeles Brick Company. (Plioto by cuuile-sy uf the coinpanjj 176 IV Sample No. Page No. 74 75 278 335 87 279 232 231 281 281 82 315 229 300 Note.- Name of -Sample.= pit from The areal ex mined in the hand, hoAvever practically con doubtful if the over such an a Mining: Th methods and ii Plant: Fac of the Alberhi and a special bone clays th; various views The clays as and elevated t bins, disc feed with an autora it. A 32-tuni Firing is dc fired with air- are fired to CO is allowed foi and two days month. One hundn twenty in the Pacific Cla 1151 S. Broa number of n operates sevei the propertie ])age 162. Douglas P Sec. 22, T. 5 Alberhill Co£ in photo No. wheelbarrow trucks which f'LAY RESOURCES AND CERAMIC INDUSTRY 177 The clays are similar to those on the adjoining Alberhill and the Gla(hlin^', MeBean properties. Pour samples were taken, as described in the foHowiiijr tab)*', wliich is arranged as a vertical section from top to bottom oi' the known ileposits: Photo No. 49. Los Angeles Brick Company, Alberhill plant, during construction. Riverside County. Photo No. 50. Los Angeles Brick Company, Alberhill plant, tunnel driers, during construction. Riverside County. Sample number Page reference Clay class number* Local nomenclature Thickness of bed, feet 108 109 110 111 290 266 298 315 6 > 7 10 Upper Douglas Douglas main tunnel Douglas Lower Douglas 5 4 7 50-70 * Refers t o clay classificat ion, described fully in Chapter IV. 12 — 54979 178 DIVISION OF MINES AND MINING Hoist Pit. Tliis is a 40-aere property, consisting of the NE^ of NE:^ Sec. 26, T. f) S., K. 5 W., and lies soutlieast of the active workings of the Alberhill company. The principal varieties of clay exposed in this pit are known as Hoist Pit blue (sample No. 112, p. 324) and Hoist Pit Photo No. 51. Lo.s Angeles Brick Company, Alberhill plant, showing' drier cars and brick represses. Riverside County. red (sample No. 113, p. 324). The blue clay is about 40 feet thick and overlies the red clay, which is about the same thickness. Both varieties are red-burning plastic clays, of particular value in the manufacture of sewer-pipe. CLAY RESOURCES AND CERAMIC INDUSTRY 179 McKnicht Clay Pit. The ]MeKniy:]it clay i)it, :^5 miles by road soiitlnvest of Corona, liiverside Connly, in Sees. ;>, I) and 10. T. 4 S., R. 7 W.. S. T>. il., has been known and worked for over :{() years. Description of Dejiosit and "\Vorkinc. 12. T. 5 S., R. 6 W. ; Terra Cotta Ei stiff'-mud ])r()cess, and fii'ed in jias-tired field kilns. The capacity of the plant is 4o,000 brick per day. The len<>th of the operating season tlepends upon local demand. Twenty men are employed. Prado Tile Company. Losse and Romedas, owners. At Prado, two miles west of Corona. This is a i)lant for manufacturing hand-made roofing tile and Jlexican pottery. The clay is mined from a local deposit and is ])ugged by treading. The ware is di'ied in air. and is fired in an oil-fired, rectangular up-draft kiln, holding about 1000 tile (4 .squares of 100 square feet). About 10 men are employed at the plant when operating. The price of the tile, at the i)lant, was $17 ])er square in 1926. Temescal Water Company. ( i) A small i)it in ])ink-mottled clay was opened up during the season of 1926 on a projierty in Sec. 35, T. 4 S., R. 6 W., about a mile southwest of the Emsco pit. The ownership of the property could not be determined, as no work was being done at the time of visit, in Se])tember, 1926. It is said to belong to the Temescal Water Comi)any, and that it was being develoi)ed by 'Doc' Meyers. The pil had lieen ojiened by an o])en cut, 25 feet wide and 40 feet long. A horse scrajier was used for removing overburden, and the clay was mined by hand methods. The only clay exi)osed was ]iink mottled, a sample of which was taken. See No. 218, ])age .'529. The extent of the deposit could not be determined, but the clay could be traced around tlx^ liill for a distance of about 200 yards. J. W. Wilson of Vidal, a station on the Parker cut-off of the Santa Fe Railroad, in San Bernardino County, has located 26 claims on an extensive clay deposit in a playa three miles by road .south of Vidal in Riverside County. The clay varies in color from nearly white to pinki.sh and blue-grey. The beds have a total thickness of at least 20 feet over the entire area, excei)t where recent erosion has removed portions of the deposit. In many places, however, thin beds of unconsolidated sandstone, from less than inch to .several inches in thickness, are interbedded with clay beds from one to three feet in thickness. The sandstone beds contain many poorly i)reserved fossils. notal)ly sharks teeth, and small clam shells less than an inch in diameter. The clav beds are overlain by varying thicknesses of loosely consolidated sand and fine gravel, but » Supplemented by data obtained by W. B. Tucker, November, 1927. 182 DIVISION OF MINES AND MINING there are large areas where erosion has removed practically all of this capping, and has exposed the clay beds. Samples No. 42 and 43 were taken for test. The results, given on ])age :U0, indicate that tlie clay is unsuited for general ceramic pur- poses, although its extremely fine grain, and high plasticity, may indi- cate certain special uses. Bibl (Clay resources of Riverside Countv) : State ]\Iining Bureau Bull. 38, pp. 221-224 and 252-253; Prel. Kept. 7, pp. 74-91. Kept. XV, pp. 559-574; XIX, pp. 185-219. Also Jour. Amer. Cer. Soc, Vol. 6, pp. 1167-1175, 1923. SACRAMENTO COUNTY. (By C. A. Logan and W. F. Dietrich.)' General Features. Sacramento County is almo.st in the geographic center of the state, and lies principally in the Great Central Valley, with the eastern ])art of the county rising into the foothills of the Sierra Nevada Moun- tains. The elevation varies from 30 feet above sea level at Sacra- mento (Southern Pacific depot) to about 900 feet above the sea on the east side of the foothills. The Sacramento and American rivers unite just northwest of Sacramento city limits, the former flowing south and forming the western county line. Cosumnes River traverses the south- eastern part of the county, flowing into Mokelumne River on the southern county line. The county and capital city are served by two transcontinental rail- ways, the Western Pacific and Southern Pacific, which cross the county from north to south. The Central California Traction Company's line from Sacramento to Stockton connects with the Santa Fe system, and the San Francisco-Sacramento electric railway runs southwest to Oakland and San Francisco. A third electric interurban line, the Sacramento Nortliern, run.s north as far as Chico. Three regular steamer lines ply between Sacramento and San Francisco on the river, giving freight and passenger service, besides which there are numerous other river cargo carriers. Two large power companies. Pacific Gas and Electric Company and Great Westcn-n Power Company, supply electric power, and the former company and Sacramento Gas Company supply gas. Transportation and power needs are thus well supplied. State highways radiate in all directions from Sacramento. Sacramento County has been an important gold-producing district for a long time. Previous to the enactment of the anti-debris laws there was considerable hydraulic mining in the Folsom district and the gold production from this source and from drift mining was as high as half a million dollars a year. In 1899 gold dredging began and gold production reached its peak between 1909 and 1919, the maximum yield being over two and a half million dollars in 1919. From now on, production from the gold dredges will decline rather rapidly. ' Ml-. T.i()Kan'.s report on Sacramento t'uunty \va.s made in 1925. See State Min- eralogist's Report XXI, pi>. 1-22. Mr. Dietrich visited some of tlie clay plants in the county iti 1925 and 192ii and has added certain details to Mr. Logan's descrijitions, especiall.v to that referring to the Natoma Clay ComiJany. He also added notes on the Michigan Bar clay deposits. In 1927. Mr. Logan visited the plant of the Valley Brick Company, and supplied the description that is included here. CLAY RESOURCES AND CERAMIC INDUSTRY 183 As a hy-jiroduct industry, ntiliziup' tho waste rock ])iles of the (Ired^red laud, tlie roek-cfusliino- industry has become important and has jrrown rapidly with the increased use of concrete. Sand and gravel are also dredged in large quantities from the American River bed. Brick, tile, and a great variety of clay products are produced, using local clay mostly. Natural ga.s is supplied for domestic use. in part from wells. Granite is quarried, and ])latinum metals and silver are recovered as by-products of dredging. Clay Resources. A few deposits of high-grade clay occur in the southeastern part of the county, adjoining Amador County. These are part of the lone formation, which is so productive of clays in the vicinity of lone. Tlie deposits were worked a number of years ago, and were the basis for establishing one of the first clay-working plants in California, but have been idle for many years, and present exposures are insufficient to warrant development", in view of the lack of cheap transportation facilities in this area. There are adequate supi)lies of common clay in the county, suitable for the manufacture of red structural ware. The gold-dredge silt now being mined by the Natoma Clay Company is of particular interest. The proximity to the important de]iosits of high-grade clays of Lincoln, Placer County, and lone. Amador County, has encouraged the estab- lishment of a number of clay plants in or near Sacramento. Cannon and Company (formerly Sacramento Clay Products Com- pany). Owner, Cannon and Company, a close corporation. D. A. Can- non, president and general manager. IMain office. 400 Forum Building, Sacramento. The plant and clay beds are at Ben Ali siding, four miles from Sacramento, on what was formerly a part of Rancho del Paso, adjoining the Southern Pacific main line and state highway. There are about two hundred acres in the holdings. A view of the plant is shown on photo No. 54. About sixtv per cent of the clay used in the plant is mined on the property. White clay and sand are brought from Lincoln and lone deposits for making fire brick and are mixed in desired projiortions with the local clay for making other products. The clay on the property is a firmly consolidated yellowish-brown sandy clay, red-burning, and locally called 'hardpan.' It is covered by alayer of reddish sandy loam, which is worked and marketed sepa- rately for molding sand. The 'hardpan' layer varies in thickness but the entire bank is similar in quality, and is worked to a depth of fifteen to twenty feet. Clay is dug by a steam shovel and horse scrapers, loaded in cars and hoisted to the plant, where it is dumped and aged under cover. It is fed by an auger feed to two dry pans for grinding, after which a bucket elevator lifts it to a Hum-Mer electric screen, screening to the desired size dei)ending on the ])roduct to be made. The clay then passes to storage biiis, pug-mills, and brick or tile machines. The stiff- mud i)rocess is used. The pr(»ducts manufactured iiiclude face brick, interlocking and hollow tile, fii-e brick, hollow tile, Roman brick and other special shapes and sizes. The shrinkage of the local clay is one in thirteen, which is low comi)ared with the Avhite clays used, and 184 DIVISION OP MINES AND MINING CLAY RESOURCES AM) CERAMIC INDUSTRY 1 So shrinkajre of different ])ro(luc*ts varies -with iiroiiortiniis of the elays employed. Fusibility of the fire briek is above :W(W Fahrenheit and the face briek 2100 to 2200- Fahreidieit. P'or burninfr the brick and tile there are five down-draft round kilns, each with a capacity of 70,000 to 80.000 bricks. The bricks are burned five days and tile two and one-half to three days. Clay workinp- machinery is o])erated from a main drive, usinji- a 20()-h.p. electric motor, and crude oil fuel is used for the kilns and steam shovel. There is a spur track to the plant from the railroad main line. Tliirty-five to forty men are emi)loyed and tlic jdant has a cai)aeity of 10,000 to 12.000 tons a month. Interlocking' tile is used for bearing walls. This tile and the face brick have been used in the new California State Life Building and in other large buildings recently erected in Sacramento. Bibl: State Mineralogist's Reports XV, ]). 404; XXT, p. 7. Michigan liar Claij Deposits. In the vicinity of ^Michigan Bar. 6..") miles north of Carbondale, are a number of exi)Osures of clay belonging to the lone formation. Attempts have been made at various times to develop these deposits, but on account of the distance from railroad transportation and the lack of large exposures of uniformly high-grade clay, no recent commercial production has been attained. Tiie most l)romising showings are in Sec. 2, T. 7 X., R. 8 E., :\I. D. :\1., on the south side of Cosumnes River, 2 miles east of Bridge House. Van Vleck and Sons of ^Michigan Bar own the north half of the section, as well as large acreages to the south and ea.st, some of which may cover deposits of future value. Geo. Cutter of Sacramento owns the XEj of the SE{ of the section; C. E. Bundock of ^Michigan Bar owns the S^ of the NW-^ of the SEj- of the section. The ownership of the remaining portions of the section was not determined. Portions of the area investigated were formerly the scene of hydraulic gold mining operations, especially near the eastern .side of the section, and extending over i)arts of section 1. Gravel still remains over por- tions of the area, in jilaces to a dei)th of 20 feet. On the Geo. Cutter pro])erty, hydraulic mining has ex])osed a bed of white plastic clay (sample Xo. 143), underlying the remnants of gravel at that point. The clay bed has a dip of 7' west, following the slope of the hill. The total expo.sed thickness of clay is as much as 20 feet in ])laces, l)ut it was not possible to find a continuous and uniform stratum of clay that is not seriously contaminated with a network of hard, weather- resisting stringers of siliceous limonite. The erosion in the 45 to 50 years since hydraulic mining days has left the iron-bearing stringers in shar]) relief on the ex])osed clay beds. At one point, near the center of the Cutter property, the clay is not greatly contaminated over an area about 50 feet square, and for a thickness of three to four feet. A sample, Xo. 148, was taken from this exjiosure, in order to indicate the ])Ossible utility of clay of such (piality, if it could be found in sufficient abundance. The test results are given on page 274. Just north of the Geo. Cutter property, on the eastern portion of the Van Vleck land, a stream hnuk affords a good exposure of a fine-grained, white- to cream- and but^'-burning clay. The expo.sed thickness of the bed varies from :] to 6 feet, extends for 200 feet in length, and can be traced in cro.ss-gullies for at least 100 feet back from the bank of the stream. This bed apparently underlies the clay exposed in the gravel 186 DIVISION OF MINES AND MINING pits. 8am])le No. 144 was taken for te.stinf?, the resvilts of whicli are •i'iveii on jiaye 27;}. It is entirely possible that prosi)ect drilling over this area, and in adjoining properties, might disclose clay dei)Osits of commercial import- ance, but in view of the minimum truck haul of 6.5 miles to Carbondale, or 12 miles to the Western Pacific Railroad in the Sacramento Valley, it is unlikely that serious work will be done until some time in the future. Muddox Pottery. H. C. INIuddox Company, owner; H. C. Muddox, president. Office and plant at Thirtieth and L streets, Sacramento. This company operates a ]ilant for the manufacture of sewer pipe and chimney ware. They own some land at Carbondale, Amador County, where they dig clay, and also buy some common clay locally. Bibl: State Mineralogist's Report XXI, p. 10. Natoma Clay Company. This company was organized to produce clay from the settling basins that have resulted from gold dredging operations in the Natoma dredging area. The clay consists of the fine clay and silt that is carried by the reject M'ater from the dredge ponds. This water is passed into shallow basins which were previousl}- formed by the dredge, and the clay and silt are completely settled before the water is returned to the main stream. During the years of dredge operation in this district, many millions of tons of clay have been artificially produced in this fashion. The individual basins are trough- .shaped, and are generally less than 30 feet deep, ranging from 75 to 100 feet wide at the surface. The sides of the troughs are formed by boulder piles on an angle of repose of approximately 45°, or by vertical banks of unmined gravel. Some of the basins are one and a half miles or more in length. Much of the clay area has been prosi)ected by hand-augers, and in one summer's prospecting alone, over 6,500,000 tons were proved. The clay is extremely fine grained, yet contains a sufficient proi)or- tion of non-plastic matter to impart desirable ceramic pro])erties to the mass. The proportion of non-plastic matter, and the fineness of grain varies from place to place, but in any given basin there is a remarkably uniform gradation from top to bottom, with the finer material nearer the surface, making it possible to mine two or three different grades of material. Many laboratory and full-scale tests have been made on the clay, and it has been found to be jiarticularly useful where an excellent range of dark-red colors and a fine even texture is desired. High dry .strength, and a long vitrification range, coupled with very low porosity when vitrified, have been thoroughly demonstrated. For the results of tests by the writer on two different samples, see No. 210 and 212, I)age 387."^ Mining operations were started in the summer of 1926, on the Alder (Jreek pit, half a mile from a spur track of the Southern Pacific Co., and one and a half miles south of Natoma. The clay is mined by an Tnsley 10-ton gasoline shovel, loading into contractor's dump cars on a narrow-gauge track. See ])h()to No. 55. Haulage to llie loading bins at the siding is done with a gasoline locomotive. Bibl: State Mineralogist's Report XXI, p. 3. CLAY RESOURCES AND CERAMIC INDUSTRY 187 Panama Pottery. Owner, Panama Pottery Company, Inc., a close corporation. Victor Axclson, president ; Andres Anderson and Gustav fJohanson, principal owners. Address, post office box 797, Sacramento. The plant is jnst sonth of Sacramento city limits near Twentj'-first Street road. See photo No. 56. Photo No. 55. Electric shovel in preliminary cut. Natoma Clay Co., at Natoma, Sacramento County. Photo No. 56. Panama Pottery Company's plant, near Twenty-first Street road, just south of Sacramento. (Fi-om State Mineralogist's Report XXI, p. 8, 1!(25.) This company owns no ehiy deposits at ]iresent, bnt buys red-burn- ino: clay locally and white clay from Lincoln and lone. The products of the plant are houshold stoneware, including jars, water coolers and filters, jugs, mixing bowls, pitchers, etc. Fancy garden pottery and 188 DIVISION OF MINES AND MINING common and fancy flower pots are also produced. Tlie company has patented a new one-])iece mold for embossed flower pots and are exclusive makers of this line which is made from cream-burning clays. See photo No. 57. Clay for the various products is crushed in a dry pan and elevated to a ;30-mesh shalving screen. It is then tempered and run throuf»'h the pug mills, aged and run through the pug mill again. After molding, it stands for a short time on shelves and is taken thence to the dryer. White ware is burned 48 to 52 hours at a temperature of 2200 degrees Fahrenheit, and red ware 87 to 42 hours at a temperature of 1800 degrees Fahrenheit. Eciuipraent at the plant includes two pug mills, a dry i)an, glaze grinder, one flower-])ot machine, three jolly wheels, shaking screen, and two down-draft kilns with a total capacity of 16,000 gallons of stone- ware. Crude oil is used for flriiig the kilns, and electricity for power. ■*ii A '♦f " 1 Kl^ 1 • 1 w. . . M - i a M4MJ fit. r 1 ^^^ SM' E 1 i wd ^^ i -*»-^' : 1 ^ 1 1 1 "tT^^^t!' ' ^-.^=ji>«.'-' ■ -2, •• i-- mi ■§ '^'■•'i'W'fcJ* • »u •4 : ■• ' i^Hl 1 JW -m •If mtry i k .■^■^lie* Photo No. 57. Fancy garden pottery, manufactured by Panama Pottery Com- pany, Sacramento. (From State Mineralogist's Report XXI, p. 8, 1925.) Sixteen men are employed. About ten days are required for a com- plete run, from setting to the time of drawing. The market for the goods is mostly in central California and deliveries are nearly all by automobile truck. Bibl: State IMineralogi.st's Report XXI, ]). 7. Sacramento Ilrivk Compani) (formerly Biverside Brick Yard). This is a .stock comi)any, subsidiary to Sacramento Navigation Com])any. W. P. Dwyer, i)resident ; A. J. Foster, general manager; H. K. John- son, secretary. JNIain office, Front and N streets, Sacramento. The brick plant is three miles south of the Sacramento city limits, near Sacra- mento River. The company makes common brick exclusively. The deposit is clay, sjind, and loam, with no hnrdpan, and is worked about 16 feet deep by CLAY RESOURCES AND CERA^flC INDUSTRY 189 51 steam sliovel and draf^-liiio scraper. Clay is loaded into four-ton side dump ears and hauled in trains by dinkey locomotives to the plant, Avliere it is (hnnpcd into I'olls. elevated to the pu^- mill and temi)ered. It passes thence to a soft-mud hi'ick machine where bricks are pressed and dusted with ground red gro'. The bank was 40 feet hip'h at the face of the pit. Pi"oni 100 to 150 tons per year were beinp; mined and shipped to Los Anofeles for use in the manufacture of face brick. Sample No. 55 was taken for testinri^», I'HuTo No. 62. W'iro Mine. Fireclay deposit east of Cardiff. San Diego County, owned by the Vitrified Products Co. of San Diego. (Sample No. 34.) inhabitants as the Wiro Mines. It is 5.7 miles by road from Cardiff in an ea.sterly direction. The fireclay has been exposed by two small open cuts, each of which is abont 50 feet square, Avith a bank of 15 to 20 feet in height. The bed of fireclay is from 10 to 12 feet thick, and is overlain by a thin layer of soil and yellow, sandy clay. The beds are nearly horizontal. Sample No. 33 was taken from the north pit, and sample No. 34 is from the south pit, and the test results are on page 2S7. See photo No. 62. Underlying the fireclay is a bed of soft, loosely consolidated sand- stone containing clay as filling material. The fire clay is moderately hard and varies in color from a buff to blue-gray and light purple. At the time of visit (June, 1925), one to two cars per week were being rained and shipped from a siding one mile south of Cardiff. Linda Vista Deposit : This deposit is located on the south side of the Santa Ee Railroad at Mile 25], about two miles north of Linda Vista Station, in Sec. 9, T. 15 S., R. 3 W., S. B. M. 206 DIVISION OP MINES AND MINING The holdintrs include the Ni and the NEJ of the SW] of the section, a total oi' 'MW aci'es. most of wliieii is appai-ently underlain by the clay beds. At the time of visit on June !), l!)2r), Ihe deposit had been opened by an electric shovel along- a face 300 feet long and 50 feet high, adjacent to and adjoining the railroad tracks. The material is a clay shale, light yellow in color, and the individual strata are from a fraction of an inch to one or two feet in thickness. Two or three beds of siliceous sandstone about one foot thick are interbedded with the clay shale. These are sorted from the clay whenever possible. In places the clay is more santly than in others, but is seldom too sandy foi' satisfactoiy use. The overburden is thin, varying from 6 inches to 3 feet in thickness. The same formation is quite extensive in this locality and can be traced for at least a mile along the Santa Fe tracks toward Linda Vista. The total thickness of the clay beds is probably not less than 100 feet. At the time of visit about 200 tons per week were being shipped to the San Diego plant. When the plant is operating at full capacity, 300 tons per w^eek are shi]>ped. 8am])le No. 32 was taken for testing. See page 322. San Diego Plant: At the plant in North San Diego hollow tile and building tile are made by mixing 25% of the Cardiff tireclay with 75% of the Linda Vista clay. The material is crushed to ^ inch and is fed from the crusher bin into a trough mixer, where it is tempered with water. The tempered clay passes through an auger machine and the tile are cut with an automatic wire cutter. The green tile are then hand-loaded on triple-deck trucks and trammed to the drying shed. When not working at full capacity, the drying is completed in three or four da3^s, but when crowded to capacit}- only one day is allowed for this part of the process. The drying is finished in oil-fired drying ovens where the heat is controlled according to the amount of moisture remaining in the tile. At times the dryer temperature is so high as to scorch the wooden pla.tforms of the trucks. The common brick are fired in open field kilns, using oil as fuel. The other shapes are fired in oil-burning round down-draft kilns. The firing temperature is from 2000° to 2100° F. for 4| to 5 days. An equal period is allowed for cooling. The firing range of the clays in use is 200° F. The brick and tile are remarkably uniform in color, which is a pink bordering on red. There is very little difficulty with lost ware and all of the products are strong and free from cracks. The drying shrinkage amounts to 1 in 11-J, and there is no cracking during the drying of the tile which are placed on the side rather than on end. The firing shrinkage is exceptionally low. The capacity of the plant is 50,000 brick and 50,000 hollow tile per day. Bibl: State Mineralogist's Reports XIV, pp. 685-688; XX, p. 369; XXI, pp. 354-358. Bull. 38, pp. 227, 254. SAN FRANCISCO COUNTY. The area of San Francisco County is 43 square miles, and tlie popu- lation is 506,676 (1920 census). The only mineral production in the county is crushed rock, sand and gravel. A number of brick yards at CLAY RESOURCES AND CERAMIC INDUSTRY 207 oiu' lime ()|)t'i-a1('(l in the county, hut hiiul is uow more valuable for otluT i)uri)oses. The only ceramic plants in the county ai-e an art ^vare pottery at 2928 Baker Street, San Fraiu'iseo, owned and oi)erated hy JaJanivich and Olsen, and a dental ])oreelain lahoratoi-y at 8:)() Market Street, known as Tara's Porcelain Lahoi'ofory. Jalanivich and Olsen are makinp: an attractive line of glazed pottery, usinf; a buff -burning body and lead glazes. Their output is all liand-niolded on a potter's wheel. It is tired in a round kiln, approximately 3-ft. inside diameter, of tlieir own design and built by the gas company, city gas being used for fuel. The clav, from California sources, is fired up to 2000° and the glaze to KiOO'^-lTOO". SAN JOAQUIN COUNTY. General Features.' The county lies mainly in the great valley of the same name in the central portion of the state. It is bounded on the north by Sacramento County, on the east by Amador, Calaveras, and Stanislaus. The latter county extends around and adjoins it on the south also. Contra Costa and Alameda counties lie west of it. Stockton, the county seat and largest city, has water transportation facilities, as well as rail. The area of the county is 1448 square miles, aiul its population is 79,905 (1920 census). By far the greatest part of its area is made up oF farm lands ; the so-called 'delta' region adjacent to Stockton being noted for its rich peat soil and heavy crops. The luost extensive geological formation exposed consists of uncon- solidated sands, gravels and clays of Quaternar\' age, which compose the nearly-level valley floor. Tlie western edge of this formation fol- lows closely the Southern Pacific railroad line down the west side of the valley from Bethany to Vernalis. The corner of the county, south- west of the railroad, is composed of marine sandstone, and diatomaceous and clay shales of Tertiary and Cretaceous ages in the northern part. Its south half is rugged and broken, as the Franciscan rocks, typical of the Coast Range, including slates, cherts, linu'stones and sandstones, witli much scliist and ser})entine, are exclusively in evidence. Unconsolidated sands, gravels and clays extend practically to the county line on the eastern side of the valley, the only other rocks exposed being two small areas of extrusive volcanic rocks, just east and north of Bellota. Comparatively few minei-al substances are found in San Joaquin County, and of these the most im])ortant are nonmetallic structural and industrial materials and natural gas. Gold, silver and platinum have been obtained by dredging in ]Mokelumne River. Clay and clay products accounted for more than half the total mineral production of the county in 1923. Clay Resources. Common clays suitable for the manufacture of brick are abundant in the county, and two brick yards are in operation. High-grade clays were at one time produced near the San Joaquin and Alameda county line, in the vicinity of Tesla and Carnegie, and were utilized at the * Laizure, C. McK., State Mineralogist's Rept. XXI, p. 1S4. 208 DIVISION' OF MIXES AXn MINIXO l)]aiit of the Carnegie Brick and Pottery Company, which has been (lisnianthMl for many years. See under Alameda County for further (h'tails. One of the important fire brick plants of tlie state, that of the Stock- ton Fire Brick Company, is operating in Stockton. The i)lant is strategically situated with res])ect to the clay mines of Amador and Placer counties, and is within the range of chea}) transportation to tlie marketing centers. San Joaquin Brick Co. I. P. Stine, secretary-manager; Ernest Rossi, jjlant superintendent. Home office, 33 South El Dorado Street, Stockton. The property is located on a 60-acre tract on Roberts Island, six miles by road southwest from Stockton. Common red brick is the sole product. The clav is an extremely sandy bottom-land loam. The water level lies within six feet of the surface, so that economical mining has always been a serious problem. A horse-scraper is used above the water level, dumping through trap doors into horse-drawn cars operating on a light industrial track. A gasoline locomotive was ])urchased and tried in place of horses for haulage, but the track was not of sufficient weight to obtain satisfactory results. Below the water level, the clay is excavated with a ^Marion steam shovel mounted on a barge. The clay is dumped along the bank, and allowed to dry in the air before it is reclaimed by the horse scraper. The soft-mud process is used for shaping the brick. The clay is given a double pugging before passing to a 6-mold press. A continu- ous rope conveyor takes the brick from the press to the drying sheds. The sandiness of the clay is indicated by the fact that the drying ])eriod in warm weather is only three days, with a maximum of five days in cooler Aveather. A Hoffman continuous kiln burning coal screenings is used for firing. The kiln is 175 feet long, with 12-ft. by 12-ft. chambers. The firing cycle is 14 days, and the capacity is 24,000 brick per day. The machinery is o])erated by electric power. The total installed ca]iacity of the motors is 100 horsepower. Forty men are employed. Bibl: State Mineralogist's Report XXI, p. 188. Stockton Brirk and Tile Co. Ralph Wilcox, president ; Paul Weston, secretary; G. Birtolini, plant superintendent. Home office, 245 North El Dorado Street, Stockton. The plant is on McKinley Avenue near the southern boundary of the city of Stockton, about one-half mile west of the Municipal Baths. A Southern Pacific spur track runs to the l)lant. The plant was built in 1921. Common brick and some hollow building tile are manufactured, using surface clay from the property. The claj^ is a bottom-land deposit of yellowish sandy loam and is mined to a depth of 15 feet below the surface by horse-drawn scrapers. The clay is found at greater depths, but is below the water level. The scrapers deliver the clay to a dry pan, from which the crushed product is elevated by a bucket elevator to a pug-mill and auger machine. The brick are taken from the wire-cutter belt by hand and loaded on trucks wliich are trammed by hand to oil-fired tunnel driers. Firing is done in a Hoffman continuous kiln. The capacity of the kiln is 450,000 brick, and 25,000 brick are set and drawn each day. Coal screenings from Utah coal are used as fuel. The coal lioles are CLAY RESOURCES AND CERAMIC INDUSTRY 209 Spaced three feet apart. One man on each 8-hr. sliift attends to the firing. The fires must be carefully controlled, as the kiln is too short for successful iirin<;' if irregular Hud nations in temperature are i)er- mitted. Natural stack draft is used. In order to keep the plant in continuous operation during the year, it is customary to shape 40,000 brick, or the ecpiivalent volume of brick and hollow tile, per day, during the summer and fall. Half of this output of green ware is stored for firing during the winter months, so that it is not necessary to operate the pit or the auger machine during the wet season. The plant emploj^s 25 men during the summer and about 15 men during the winter. The annual output is over 3,000,000 brick, or an equivalent volume of brick and hollow tile. The hollow tile production is never a large proportion of the total. All machinery is operated by electric power. Bibl: State Mineralogist's Report XXI, p. 188. Stockton Fire Brick Co. John T. Roberts, i)resident ; Percy T. Cleg- horn, secretary ; E. H. Horner, plant superintendent. JMain office, 12 Russ Building, San Francisco. Plant address, P. 0. Box 314, Stockton. The company's plant is just west of the Southern Pacific railroad at the foot of S. California Street, Stockton. See photos No. 6:} and 64. The outi)ut includes several different grades of fireclay brick and special shapes, high-temperature fireclay cement, and diatomaceous insulating brick. The companj^ owns or leases deposits of most of the raw materials in use at the plant, the most important of these being Edwin clay (No. 120, p. 272), from Jones Butte near lone; lone sand (No. 140, p. 280), from the pit of the lone Fire Brick Co., and Lincoln fireclay (sample No. 280, p. 305), from the newly developed pit of a subsidiai-y company, the Clay Corporation of California. Quartz for grogging some of the grades of fire brick is purchased from various California sources, mainly in Placer County, and diatomaceous shale for the manufacture of insulating brick and special shapes is purchased from producers in Santa Barbara County. The princii)al grades of fire brick are as follows: 'Gasco XX," quartz grogged, auger-made, single pressed ; ' Stockton, ' quartz grogged, auger- made, repressed ; ' Gasco R, ' quartz grogged, auger-made, repressed ; and 'Carnegie,' which is grogged with calcined fireclay, hand-made in sanded molds, and repressed. The 'Carnegie' brick is the best grade of standard brick being produced at present for resisting high tem- peratures under adverse load and spalling influences. Among the specialties regularly produced are a high-grade checker-brick which is made from a mixture grogged with calcined clay and shaped on an end-cut auger machine, and runner-brick, made from a similar mixture, formed on an auger-machine, and then passed to a specially designed machine for making the joints and cutting the side-holes. The mixtures are prepared by dry-pan grinding, followed by pug- mill tempering for the material that is to be hand-molded. All of the shapes except runner brick are dried in waste-heat tunnel driers. The runner brick, which require especially uniform drying on all sides during the shrinkage i)eriod, are dried in a Carrier ejector humidity drier, which is operated on a 13 to 15 hr. schedule, beginning 14—54979 210 DIVISION OF MINES AND MINING 'tm V 1 '■ 1 t??IB j 1 4 1 p 4:- -' ji *, — ^ m^ ^h if: iBsjS'' 1 Sh ■ M 1 1 c o y V 3 O rj 3 O c m c o -t-t X o o O U a "u H fa c o a o J3 CO to d O o K CLAY RESOURCES AND CERAMIC INDUSTRY 211 with a tliree-hour [xM-iod at Ho"" F. and 40'/ humidity, and finished at 240° to 250 F. with steadily declinin<>- humidity. The brick are set on tlie drier ears in a direction parallel to the dii-eetion of the air current in the drier, so that the air passes tlirou^ih and around the brick simultaneously, thus drying the inside and outside of the brick at the same rate. The manufacture of diatoniaeeous insulating' brick, known by the ti-ade name 'Diatex,' is becoming an increasingly iini)ortant part of the 0|)erations of the phmt. Standard 9-in. brick and many special shapes are made. They are liaud molded from diatomaceous shale containing sufficient clay for boiidiiiu. Slow and cai-eful uniform drying is neces- Photo No. 64. Clay bins and dry pans In plant of the Stockton Fire Brick Company. (Photo by courtesy of the company.) sary to avoid loss by warping or cracking. In connection with the development of this i)roduct a conductometer, the i^rinciple of which has been described by K. I). Pike,^ was constructed in the laboratory, for the purpose of comparing the heat conductivities of the various experimental mixtures. The fireclay ])roducts are fired in 12 oil-fired round down-draft kilns, which are of various sizes from 12-ft. to :32-ft. in diameter, with capacities ranging from 80 to 400 tons each. The usual firing cycle is seven to eight days firing, to a temperature of 1370° C, correspond- ing to cone 11 down, followed by a cooling period of equal length. • Pike, R. D., Need for more refractory heat insulators : Pro])osed conduetometers for measuring thermal conductivity: Jour. Amer. Cer. Soc, 5, 554, August, 1922. 212 DIVISION OF MINES AND MINING The insulating brick are fired in fonr 12-ft. hy 23--ft rectangular kilns. liJase-metal thcrinofouijles with automatic recorders are installed in all kilns for the accurate control of the firing cycle. The plant is noteworthy for the high degree of technical control to which all operations are subjected, and for the continual improvements that are being made in the processes of manufacture and in the (juality of the finished product, through the cooperation of an efficient technical staff and a progressive management. An average of 110 men are employed. Bibl (Clay resources of San Joacjuin Count v) : State Min. Bur. Bull. 38, pp. 227-228; Prel. Kept. 7, pp. 91^95; Kept. XIV, pp. 607-610, and XXI, pp. 188-190. SAN LUIS OBISPO COUNTY. General Features.^ San Luis Obispo County borders on the Pacific Ocean and occupies a position midway between San Francisco and Los Angeles. It is bounded on the north by Monterey County, on the east by Kern and on the south by Santa Barbara. It contains 3334 square miles and has a population of 21,893 (1920 census). The coast line of the South- ern Pacific railroad passes through the county from north to south. The railroad follows Salinas River Valley through Paso Robles to a point near Santa Margarita, thence it crosses the Santa Lucia Range via Cuesta Pass, reaching San Luis Obispo at the foot of the grade, and the ocean near Pismo. It continues south along the ocean shore, giving through transportation. The Pacific Coast railroad (narrow gauge) connects Port San Luis with San Luis Obispo and continues to Santa Maria and other points in Santa Barbara County. The paved coast highway closeh- parallels the Southern Pacific railroad through the county. From Santa Margarita fair dirt roads extend to the eastern part of the county, but McKittrick, in Kern County, is a nearer railroad point to this section. Steamer service is available at Port San Luis. This harbor is the terminus of pipe lines from the San Joaquin Valley oil fields and is an important loading point for oil tankers. The Coast Range mountain system traverses the county from north- west to southeast. Within the county this mountain block consists of three main ranges, the Santa Lucia Mountains, the San Luis Range, and the San Jose Range. The geology of that portion of the county from the southern boundary to latitude 35° 30' N. and from the coast "to longitude 120° 30' W. has been described and mapped in detail by H. W. Fairbanks.- A discus- sion of the geology of the countv with relation to petroleum resources will be found in Bulletins Xo.' 69 and Xo. 89 of the State Mining Bureau. A folio of geologic maps accompanies Bulletin Xo. 69. As indicated on the Bureau's geological map of the state, the Santa Lucia Range from San Luis Obispo northwestward to the northern boundary line is made up of Franciscan rocks, including slates, cherts, ' From Laizure, C. McK., San Luis Obispo County : State Mineralog-ist's Rept. XXI. pp. 499-501, 1925. = Fairbanks, H. "W^, San Luis Folio, No. 101 : U. S. Geological Survey. CLAY RESOURCES AND CERAMIC INDUSTRY 211] limestones, aii,d sandstones, witli nuicli serpentine and many dikes and intrusions of deeji-seatod iji'iieous roeks. On the tlanks of tlie range are narrow belts of Cretaeeous sandstone and shales. Southeast of San Luis Obispo the formations are mainly Tertiary marine sandstones and diatomaeeous shales. Unconsolidated sands, jijravels, and clays extend from Pismo to Santa IMaria River and well up tlie valley of the Santa Maria. East of Santa Margarita there is a large area in which granite predominates. The balance of the county lying east and north of the Santa Lucia Range consists almost entirely of sedimentary rocks of Tertiary age, shales, sandstones, tuffs, and gravels with an area of Quaternary sediments comprising Cai-rizo Plain. Among the mineral resources of the county, both developed and undeveloped, are asphalt, bituminous rock, brick, chroniite, coal, copper, diatomite, gypsum, iron, limestone, marble, mineral water, onyx, l)etroleum, quicksilver, soda, aiul miscellaneous. Miscellaneous stone, l)etroleum, brick, and mineral water are the principal commercial mineral products at present. Clay Resources. There are no known deposits of high-grade clays in this county, but red-burning clays suitable for making brick occur in the vallej^ silts of recent origin at various places. Since the population of the county is small, the demand for claj' i^roducts is limited, and a single common- brick plant at San Luis Obispo sup])lies the market of the county as well as of a few nearby towns in Santa Barbara and Monterey counties. The territory to the south is supplied by brick yards in Santa Barbara, while plants in San Jose furnish brick for the communities in Monterey and San Benito counties. San Luis Brick Works. Owned and operated by Faulstick Bros., San Luis Obispo. This plant, formerly known as the San Luis Brick C^ompau}', is located one mile south of town, near the lines of the Soutliern Pacific and Pacific Coast railroads. The clay is a yellowish loam, with little or no overburden. The proportion of sand is sufficient to prevent excessive shrinkage and cracking in the brick-making pro- cess, yet is not so high as to interfere with the binding proj)erties of the clay. The clay is mined to a depth of 15 feet by hand shoveling into dump cars, which are hauled up an incline by a steam winch, to dump through a hop])er into a 10-foot dry pan. After screening, the fines pass to a ])ug-mill, then to an American Clay Machinery Co. auger machine e()uipi)ed with a Preese cutter. The oversize from the screen is returned to the dry pan. The brick are dried in the open without auxiliary heat. This requires an average of three weeks. P.iirning is done in open field kilns, usually Avith 18 arches, each kiln containing 590,000 brick. Heat is supplied by oil, with steam atomization. Firing requires five days, and cooling about three weeks. The plant operated three months during the season of 1925, producing about 1,500,000 brick. Twenty-eight men are employed when in full operation. See ))hoto No. 65. Bibl: State Mineralogist's Report XXI, ]). 505. Santa Margarita. Two miles south of Santa IMargarita is an extensive undeveloped deposit of red-burning shale. The deposit is easily 214 DIVISION OF MINES AND MINING p i E o y to 8-^ o . Oo O o p. CO aj 1—1 to c +-' S.2 o |1 |S ?^ o O CLAY RESOURCES AND CERAMIC INDUSTRY 215 accessible at a point 2.0 miles (by road) south of the center of 8anta ]Marj;arita, where it lies in a broad belt between the state hij^hway and the Southern Pacific railroad for a distance of at least one-half mile. The strike of the beds is S. 25° E., and the dip is 75° NE. Two samples were taken. No. 216 was taken from a road cut, 2.0 miles from Santa ]Mai'<>ai-ita. Sample No. 217 was taken from the same formation, 2.5 miles from Santa Marlant. The plant is equipped with three kilns, fired with oil. L. L. Brentner. Carpinteria. The property is west of the coast highway, 14 miles north of Ventura, and four miles south of Carpin- teria. Ten acres were at one time under lease to the Builder's Supply Company of Santa Barbara, who operated a plant for the manufacture of common brick. It is understood that the proi)erty is now idle (1927). The clay beds are nearly vertical, have an east-west strike, and are about 200 feet thick. The material is a light-colored thin-bedded shale, with quartz, limestone, and sandstone boulders, which were i)artly removed by screening. A drag-line scrajjcr was used for mining. The plant is equipped with crushing machinery to deliver a 20-mesh product to the brick plant, which consists of a 14-ft. pug-mill and an auger machine, with a wire cutter. The brick were dried in the open and fired in oil-fired field kilns. Sample Xo. 3 was taken for testing, the results of which are on page 348. The material is not of good quality for the manufacture of brick. Bibl: State Mineralogist's Rept. XXI, pp. 546-547, 1925. Muengenherg and WhitiJcer. R. ]\Iuengenberg and E. H. Whitiker, of 230 de la Guerra Street, Santa Barbara, are operating two of the brick yards formerly opei-ated by the Builder's Supply Company in Santa Barbara and Montecito. The Santa Barbara plant, formerly the Parker Brick Company, is on West Montecito Street, one-half mile from the Southern Pacific railroad tracks. Common red brick, hollow building tile, and drain tile are made from clays obtained from ]iits on the i)lant site and from other sources in the vicinity. The stiff-mud process is used. The ware is dried in the open, and fired in oil-fired field kilns. Samj^le Xo. 1 Avas taken for test, the results of which are on ])age 338. Tlie sample was taken from the i)ug-mill, and is typical of the class of material available in the district, and for which the plant ha.s been designed, rather than being rej^resentative of a specific clay bank. The Toro Canyon plant, formerly the Toro Canyon Brick and Tile CLAY RESOURCES AND CERAMIC INDUSTRY 219 Company, is in Torn Canyon, near IMontecito. There is an anii)U' sup- ply of plastic clay, interinintrled with blocks of soft, yellow sandstone. The clay is mined from a sliallow side-hill open cut with tractors and scrapers. Connnon red brick, hollow buildinji' tile, and roofin**' tile are made. Drying' is done under sheds and in the open, and oil-fired field kilns are used for firing. Sample No. 2 (see p. 338) was taken. Bibl: State Mineralogist's Repts. XV, p. 735; XXI, pp. 546-547. Bull. 38, p. 25(i. Prel. Kept. 7, p. 96. SANTA CLARA COUNTY. General Features. Santa Clara County lies in the west-central portion of the state. Tt is bounded on the north by San ^lateo and Alameda counties, on the east by Stanislaus aiul Pierced, on the south by San F)enito, and on the west by Santa Cruz and San ^lateo. The area of the county is 1328 square miles, and the jiopulation is 100,588 (1920 census). The prin- cii)al towns are San Jose, Palo Alto, Santa Clara, and Gilroy, all of which lie in a broad valley between two ))arallel ranges of the Coast Range system of mountains. This valley is noted as one of the most productive fruit-growing sections in California. The g-eological formations that are most widespread in the county are Quaternary sediments in the valleys, and Franciscan (Jurassic), Cretaceous, Pliocene, and Pliocene formations in the mountains. The New Almaden district, about 15 miles south of San Jose, was for many years famous as a (quicksilver producer, but the production has declined in recent yeai's owing to the exhaustion of the mines. The following' mineral products are produced commercially : brick, clay, limestone, magnesite, mineral water, natural gas, petroleum, quicksilver, and miscellaneous .stone. Of these miscellaneous stone, brick, and quicksilver are the most important, in the order given. Occurrences of chromite, manganese, and soapstone are known. Clay Resources. No commercial dei)osits of high-grade clays are known in the county. Common clays suitable for the manufacture of brick and tile are abund- ant throughout the valley i)ortions of the county. On account of favorable manufacturing and marketing conditions, a number of clay- working plants have been established in and near San Jose and Santa Clara. Some of these ]ilants use common clay from extensive deposits along Coyote Creek within the city limits of San Jose. The clay bed is from 15 to 20 feet thick. Garden City Pottery Company.^ H. ]M. Stammer, president; D. Raymond, vice president ; N. J. Mahan, secretary. Office and plant at 560 N. Sixth Street, San Jose. This com])any was established in 1904, under the name of the Garden City Pottery. The products of the plant are flower pots and stoneware. Lincoln clay is used for the strneware, and a local red clay, from Coyote Creek, is used for flower ])ot.s. The stoneware mix is prepared by grinding, washing, and filter- I)ressing-, followed by pugging. After shaping, the ware is dried in steam-heated drying; rooms for a period of three or four days. ^Data obtained by D. R. Irving, Stanford University. 220 DIVISION OF MINES AND MINING Firing: is done in four round down-draft kilns. Two of the kilns are 20 feet, and the other two are 18 feet in diameter. They are fired with oil, which is atomized with steam. The stoneware is fired to 2200° F. (about cone 5) in 72 hours, and the flower pots are fired to 1800° F. (about cone 07) in 48 hours. The plant operates throughout the year and employs 30 men. Bibl : State Min. Bur. Bull. 38, p. 229 ; Prel. Rept. No. 7, p. 96. Gilroy Brick and Tile Company. Chas. Bolting, Gilroy. Mr. Bolting built and operated a small common brick plant for a few years on his ranch about one mile north of Gilroy, using a clay shale obtained from a deposit on the Redwood Retreat Road, about eight miles from Gilroy. The plant was not commercially profitable, and has been partly dismantled. Kartscho'ke Clay Products Compan]i. G. Kartschoke, president and manager. Plant at 1098 S. Third Street, San Jose. The principal products of the plant are sewer pipe, flue lining, and patent chimney pipe. The plant is also equipped to make machine-made roofing tile. The clays are obtained from banks along Coyote Creek, with the addi- tion of some clay that is purchased from the Yarn deposit in Amador County. The clays are ground in a dry pan and elevated to a double-shaft pug- mill, from which the mix passes to an American sewer pipe press. Drying is done in a building which is heated by steam during the win- ter. Four to five days are usually required for drying. The ware is fired in three oil-fired round down-draft kilns, 22 feet, 26 feet and 28 feet in diameter, respectively. Cone 2 (1165° C.) is reached in 80 to 90 hours, the entire cycle, including setting and draw- ing, requiring about two weeks. Bibl: State Mineralogist's Rept. XIII, p. 618; State Min. Bur. Prel. Rept. 7, p. 97. J. B. King, of Skyland, P. 0., Wrights Station (Santa Cruz County). It is reported that there is a "fine, large deposit of pottery clay" on this property. No investigation was made. As the locality is relatively inaccessible, near the summit of the Santa Cruz Mountains, the clay would need to be of exceptional quality to be of commercial importance. Piatt's Premier Porcelain, Incorporated.'^ H. D. Melvin, president; A. A. Baker, vice president ; N. E. Wretman, secretary. Office and plant on Lafayette Street, Santa Clara. This company makes sanitary porcelain from a mixture of English china and ball clays, Arizona feldspar, and California silica. The feldspar and flint are received at the plant in pulverized form. The mixes are prepared by blunging and filter-pressing. The ware is shaped by the casting process, although hand-pressing was formerly used, and is dried in steam-heated rooms for a period of one week. Three 16-ft. round ui)-draft ('bottle') kilns are used for firing. These use oil fuel, atomized with steam. The biscuit ware is fired to cone 9 (1250° C.) in 36 hours, and the glost ware is fired to cone 8 (1225° C.) in 30 hours. Tlie jdant was idle during 1927, but expected to resume operations early in 1928. • Data obtained by D. R. Irving, Stanford Univer.sity. CLAY RESOURCES AND CERAMIC INDUSTRY 221 EcmiUard Brick Company. C. Kciuillard, president ; R. C. Giroux, secretary. Office, Xi2 Plielan r>iiil(liii«i-, San Francisco. This company has operated a brickyard at IMcasanton, Alameda County, for many years, and has recently established a plant in San Jose, on Storey Koad, on the eastern edge of town. Common red brick are made from a local clay, nsin«i- open field kilns for firing. The plant is operated for about eight months during the year. San Jose Brick and Tile Company. J. J. Jainiesen, president; R. L. Richards, secretary-treasurer. Address P. 0. Box 274, San Jose. The plant is on Fruitvale Avenue, and the property comprises 85 acres. Common red brick is manufactured. The clay deposit consists of a 30-ft. bed of red-brown plastic clay overlain by three to five feet of soil. The clay is mined and clelivered to the plant by a drag-line scraper. The plant is equipped with an E. M. Freeze K-B brick machine, which has a capacity of 75,000 brick per day and is driven by a 150-h.p. electric motor. An industrial ear system is used in the drying and kiln yard. Diying in open racks requires from seven to eight days. One round down-draft kiln and two down-draft continuous kilns are used for firing. Coal screenings are used as fuel. The firing schedule of the continuous kilns is as follows: three days Avater smoking, four days firing and ten days cooling. The plant is usually operated for nine months of the year, employing 50 men, and using 345 h.p. of electric power. The average fuel con- sumption is 300 lb. of coal per thousand brick. San Jose Tile Companij. A partnership, consisting of L. W. Austin, D. W. Wallace, L. F. Wallace, W. D. Rice, and L. II. Bruns. The plant is at 333 S. Eighteenth Street, San Jose, on the banks of Coyote Creek. Hand-made floor, wall, and mantel tile are manufactured, using a red- burned body consisting largely of clay from the Natoma Clay Comi)any in Sacramento County. Local clay from Coyote Creek and some Lin- coln and lone materials are used to a certain extent. The equipment consists of a disintegrator and pug-mill, and a rectangular kiln, burn- ing oil. The kiln is equipped with a pyrometer. The firing period is from 40 to 48 hours, finishing at cone 5 (1180° C), or higher. An excellent market has been established for the ware, and the plant is expected to grow rapidly. 8 & S Tile Company. A. L. Solon and F. P. Schemmel, owners. Office and plant at 1881 S. First Street, San Jose. This company specializes in the manufacture of decorative tile, both glazed and unglazed, from a huff, or red-colored body. Local clay from Coyote Creek is used in conjunction with Lincoln clay and lone sand. Biscuit re.iects and kiln dirt are used as grog. The clays are mixed in batches on the floor, fed to a Jeffrey swing- hammer mill, and elevated to a bin, from which they are fed by a disc feeder to a pug-mill. A INIuller auger is used for shaping all plain tile, whereas fancy tile is hand-pressed in plaster molds. Some dry-pressed tile are made at times. A specially designed waste-heat drier is used. To secure partial humidification, the drier is arranged so that the hot air can be retained in closed circuit. Drying requires three days. Two oil-fired round kilns are used. These are 18 and 22 feet in diameter, respectively. They are fired to cone 2 (1135° C.) in 48 hours. Cool- 222 DIVISION OP MINES AND MINING ing: requires four days. Both kilns are ecinipped Avitli base-metal thermocouples. All j^lazed ware is biscuited first, then .ulazed. About eight men and six women are employed. SANTA CRUZ COUNTY. General Features.' 8anta Cruz County borders on ]\Ionterey Bay and the Pacific Ocean, south of San Mateo County, and north of ^Monterey County. Its area is 435 square miles, and the population is 26,269 (1920 census). The oreater part of the county is rugged and mountainous. The geology of most of the county is described in U. S. Geological Survey, Santa Cruz Folio, No. 163, by J. C. Branner, J. F. Newsom, and Ralph Arnold. The principal sedimentary formations are of Miocene and Pliocene age. There is an extensive area of quartz-diorite, and smaller areas of metamorphic schist, marble, and limestone. The mineral production of the county includes cement, lime, lime- stone, and miscellaneous stone, and bituminous rock. Clay Resources. Common brick clays occur along the San Lorenzo River and at other points. In the early nineties, two brickyards were in operation near Santa Cruz, but these have long since been dismantled. Clay is being mined at Tank Siding, 1.8 miles southwest of Glenwood, and at Daven- port, for use in the manufacture of cement at the j^lant of the Santa Cruz Portland Cement Company, at Davenjjort. Bibl: State Mineralogist's Repts. X, p. 625; XII, p. 383; XIII, p. 619; XVII, p. 234; XXII, pp. 78-79. Prel. Rejit. No. 7, p. 97. SHASTA COUNTY. General Features. Shasta County lies at the northern end of the Sacramento Valley. Redding, the county seat, is on the Shasta line of the Southern Pacific Railroad, 175 miles north of Sacramento, and is the principal rail- road and supply point for Shasta and Trinity counties. The Pacific highway connecting California anfl Oregon, traverses the county in a north and south direction, paralleling the Southern Pacific railroad in the Sacramento River Canyon. The area of Shasta County is 3858 square miles and the population in 1920 was 13,311. The southern ])ortion of the county adjacent to the Sacramento River is open and rolling, and is devoted to farming and stock raising. The northern and western ])ortions of the county are mountainous, and the eastern ])ortion is a succession of rising plateaus covered by recent volcanic flows. ]\Iost of the important mineral deposits of the county are confined to the western half. The Pit River, which joins the Sacramento River near Redding, is an import- ant source of hydro-electric ]iower. Timber is an important resource of the county, especially in the eastern portion. Shasta County is characterized by the variety of its geologic forma- tions, and the diversity of its mineral resources. Copper, gold, zinc 'See Laizure, C. McK., Santa Cruz County : State Min. Bur. Rept. XXII, pp. 68-93, 1926. CLAY RESOURCES AND CERAMIC INDUSTRY 223 and iron aro the principal metals thai liave been produced in the county. The limestone resources are very extensive, but to date have not been exjiloited on a lar«re scale. Ext(Misive beds of low-«»rade lij,niile occur in the central part of the county. These have been investigated many times in the past, and an attempt is now being made to place them upon a sound commercial basis. Clay Resources. Tliere is at present no clay industry in the county. At various times in the past, brick yards have been operated at Redding and Anderson, to supply local needs, but these have been idle for many years. There is an abundant sui)ply of clay and silt suitable for common-brick manufacture in the flood plain of the Sacramento River south of Redding, and along other streams in the county. No commercial deposits of high-grade clays have yet been discovered in the county. It is possible that with the serious development of the lignite properties northeast of Oak Run, mainly in T. 33 N., R. 1 W., M. D. M., refractory clays may be encountered, as the lignites occur in the lone formation, which is the important source of terra cotta and fireclays in I^lacer and Anuulor counties. A small samjile of micaceous kaolin, slightly tinged with iron, was supplied by Mr. I. J. Johnson, of the Johnson Iron Works, Redding, but no data could be secured as to the source of this nuitcrial, excei)t that it was found on a property some 20 miles northeast of Palo Cedro. For convenience of reference, the following descrii)tions of common- brick clay deposits are abstracted from previous publications of the Bureau : State Mineralgist's Report XXII, p. 131, 1926; Prel. Rept. No. 7, p. 98, 1920. Holt and Gregg, J. N. Gregg, president, Kennett. A brick j)lant was formerly operated at Anderson, in Sec. 17, T. 30 N., R. 4 W., M. D. ]\I. The deposit was 15 feet thick. Block 29, Bedding Grant, 1] miles south of Redding. Clay bed six feet thick. A brick kiln was operated here many years ago. Bedding Brick and Tile Compamj f(n-mer]y ojierated a dei)osit on 40 acres in Sec. 19, T. 31 N., R. 5 W., M. D. M., and made brick in small kiln at Redding. Bedding Homestead Deposit is on the Sacramento River east of Cottonwood. Deposit is a mile long by one-fourth mile wide and contains 30 feet of clay, covered by 15 feet of sand and gravel. Unde- veloped. No recent information available. Southern Pacific Company owns an undeveloped clay deposit in Sec. 19, T. 32 N., R. 4 W., M. D. M. In addition to the foregoing, a deposit of fireclay is reported in Sec. 24, (34?) T. 34 N., R. 5 W., M. D. M., that was at one time operated by Holt and Gregg for use as kiln lining. No recent information since the report of 1920. 224 DIVISION OP MINES AND MINING SISKIYOU COUNTY. General Features. Siskiyou County borders on the state of Oregon in a sparsely-settled mountainous portion of California. The total area of the county is 6256 square miles, and the population (1920) is 18,500. The county is traversed by the Sliasta line of the Southern Pacific railroad. The principal industries of the county are lumbering, stock-raising and farming. The mineral industry of the county is not at i)resent of great importance, although in the past the county has been celebrated for its placer mines, and during the late war it was an important source of chromite. The geology and mineral resources of the county have been discussed in a recent report.^ Clay Resources. On account of the remoteness of the county from the centers of popu- lation and the small population within the county itself, none but exceptionally high-grade clay deposits could have commercial value. A deposit of 'pottery clay' 16 ft. thick has been reported- in Sec. 8, T. 43 N., R. 6 W., near Gazelle. A careful search for this deposit was made in August, 1925, and local inhabitants were questioned concern- ing it, but no knowledge of such a deposit could be obtained. The report probably refers to a deposit of yellow plastic clay that occurs on the pro})erty. A de])osit of fireclay in the roof of a coal mine in Sec. 26, T. 46 N., R. 6 W,, has also been reported ^ but could not be verified. The coal mine referred to is now inaccessible. Common brick clays occur in irregular alluvial deposits at various places in the county. Some of these, near Yreka, Etna Mills, and Fort Jones have been used in the past for producing brick for local use during the early construction periods of the larger towns in the county. None of the brick yards have been operated for many years, and have long since been dismantled. If at any time in the future it should become necessary to manufacture small quantities of red brick in the county, enough clay of satisfactory quality could probably be found, but it is unlikeh' that large deposits of uniformly good material will be encountered. For convenience of reference, the previous reports of the bureau on common clay deposits in Siskiyou County are summarized below, but as these reports are over 20 years old, the names of the men who were formerly associated with the deposits are omitted here, as few of them can now be found. T. 43 N., R. 9 W., M. D. M. Surface clay deposits were reported in Sec. 2, 11, 21 and 32, in the vicinity of Fort Jones, Green view, and Etna. These clays have been used for brick making. Sec. 27, T. 45 N., R. 7 W. Bricks were once manufactured from a reddish clay near Yreka. Near Montague a small quantity of brick clay has been found. Bibl : Cal. State Min. Bur. Bull. 38, p. 230 and 257, 1906 ; Prel. Rept. No. 7, p. 98, 1920 (a copy of the material in Bull. 38). ' state Mineralogist's Report XXI, jip. 413-498. 1925. = Prel. Rept. No. 7, p. 99. ' Op. cit., p. 98. CLAY RESOURCES AND CERAMi:' INDUSTRY 225 SOLANO COUNTY. General Features.' Solano County i-adiates in a northeasterly direction from San Pablo Bay, an arm of San Francisco Bay. Its area is 822 square miles, and the jiopulation is 40,602 (1920 census). About 80 per cent of the land is arable and the balance is mountainous. Cretaceous and Ter- tiary sediments, and late Tertiary (probable) lavas are found in the mountainous portion of the county. The rest of the county is covered with Recent alluvium. Among the mineral resources of Solano County are cement, clay, fuller's earth, limestone, mineral water, natural ji'as, onyx, quicksilver, salt and miscellaneous stone, llecent production has been confined to cement, miscellaneous stone, mineral water, onyx and travertine. The only cement plant in the county was closed down in November, 1927, aiul is available as a stand-by plant. Clay Resources. Common brick clays are abundant in the argicultural section of the county. A number of clay-working plants, including a pottery at Renicia and brick and tile plants at Vallcjo, were active a number of years ago. Steiger Brick and Tile Company (formerly the Vallejo Brick and Tile Company). Plant two miles northwest of the center of Vallejo. This is the latest attempt to operate a bricln^ard in the county, and operations were discontinued in 1923. The plant is equipped for the manufacture of brick and hollow tile. The clay deposit is a yellow siiale, an analysis of which is reported by Laizure- as follows: Loss on ignition 8.03% Silica 57.83% Alumina 19.52% Iron oxides 7.46% Calcium oxide 1.24% Magnesium oxide ^ 2.06% Alkalies (by difference) 3.86% 100.00% Clav from a bank at the base of the hills near Goodvear Station was utilized about 20 years ago in a pottery. Bibl : State Mineralogist's Repts. VIII, p. 631 ; XIII, p. 619 ; XIV, ]). 300; XXIll, pp. 204-205. State Min. Bur. Bull. 38, p. 258. Prel. Rept. No. 7, p. 99. SONOMA COUNTY. General Features.' Sonoma County is situated north of IMarin County and San Pablo Bay, extending eastward from the Pacific Ocean, which it borders for 50 miles, to the crest of the Coast Range, which forms the boundary .separating it on the east from Lake and Napa counties. Mendocino County bounds it on the north. The land area of the county is 1577 ' See Laizure, C. McK., Solano County : State Mineralogist's Rept. XXIII, pp. 203-213, 1927. = Op. cit., p. 204. 3 From Laizure, C. McK., Sonoma County : State Mineralogist's Rept. XXII, pp. 327-329, 1926. 15—54979 226 DIVISION OF MINES AND MINING square miles, and tlie poi)ulation is 51,990 (1920 census). Tliere are no ini{)rove(l harbors on the coast side, but water shii)i)ing facilities are available in the southern portion, which borders the bay. The North- western Pacific railroad traverses the county from south to north throufih the central valley, with branch lines into Sonoma Valley, to Sebastopol and to the Russian River region around Guerneville, Dun- can Mills and Cazadero. A narrow-gauge branch also extends from Marin County northward through Valley Ford to ]\Ionte Rio in the western part. A line of the Southern Pacific railroad from Xapa Junction in Xapa County traverses the Sonoma Valley and terminates at Santa Rosa. The Petaluma and Santa Rosa electric system also gives service to the southern portion of the county. The paved 'Redwood Highway' of the state system closely i)arallels the Northwestern Pacific railroad through the county. Its main laterals are also paved or well- kept graveled roads. The county produces a great variety of agricultural products, and dairying and stock-raising are important sources of wealth. Its min- eral deposits have been exploited more or less continuously since the sixties, and although it can scarcely be classified as a 'mining' county, metals and nonmetallic minerals exceeding $11,000,000 in value have been produced to date. Its resources are still far from exhausted. Many health-giving mineral springs are found here, and its resorts have made the county one of the favorite playgrounds of central California. Situated in the midst of the Coast Range, its topographic features include level valleys, Ioav rolling hills and rugged mountains, with deep- cut canyons. The drainage of the southern portion is to the bay, while that of the northern two-thirds is to the Pacific Ocean, chiefly by the Russian River and its tributaries. The main valley area, beginning at the bay, extends through the center of the county for about 60 miles, with an average width of 25 miles, but narrowing toward the northern end. Numerous smaller valleys separate the lesser spurs and ridges of the main range. "^f?^ Geology. Sonoma County is not covered by any of the Ignited States Geological Survey Folios, and the geologic literature on this area is fragmentary. The general geology has been described in part by Osmont,^ and bj' Vander Leek,- in its relation to possible oil production. The geology of the quicksilver ore deposits has also been covered in considerable detail by various writers. As shown on the State Mining Bureau's geological map of the state, the Franciscan rocks of the Coast Range cover probably three-fourths of Sonoma County, extending in a broad belt from the ^larin County line northwesterly the entire length of the county and beyond. This belt of metamorphic rocks widens toward the north. It consists mainly of sandstone, with smaller amounts of limestone, slates, cherts, schist, and much serpentine. Bordering the coast from Salmon Creek north, is a belt of Cretaceous sandstone and shale a few miles in width. Ter- tiary sedimentary rocks are exposed in a small area around Valley ' Osmont, V. C, A Geological Section of the Coast Hanges North of San Francisco : Bull. Dept. of Geol.. University of California, Vol. 4, No. 3, pp. 39-87. - Vander Leek. Lawrence, Petroleum Resources of California : State MJn. Bur. Bull. 89, pp. 36-38. CLAY RESOURCES AND CERAMIC INDUSTRY 227 Ford. The main valley area is conii)Osed of Quaternary sands, frravels, and clays aloii^' the Russian River from Cloverdale to Ilealdsburg. These foi-mations nai'i-ow at Wiudsoi- and then widen a^ain between Forestville anil Santa Rosa and continue south throutrli Sebastopol and Cotati nearly to Petaluma. The lowlands area around the mouth of Petaluma Creek and Sonoma Creek is also of Quaternary alutt' for manv years. Banks of clay of fine quality are reported in the Flounwij di.strict.' Plournoy is in T. 24 N., R. 5 W., about fourteen miles west of the Southern Pacific railroad at Corning. iVo investigation was made of this occurrence. O'Connor Brotlicrs liricki/ard. Address, Red Blutf. The clay deposit and brickyard are on the Reed Tract, in Sec. 29, T. 27 X., R. 8 \V., M. D. M. The deposit covers an area of over 19 acres, and is from 8 to 12 feet thick,, underlain by gravel. The soft-mud process is used, a small brick ]iress being ojierated by horse power. The brick are fired in open field kilns. The plant is operated intermittently to supply the local demand. Bibl : State Mineralogist 's Rept. XV, p. 260 ; State Min. Bur. Bull. 38, pp. 258-259 ; Prel. Rept. 7, p. 100. TULARE COUNTY. General Features. Tulare County is in the southern San Joaquin Valley, and is bounded on the north by Fre.sno, on the ea.st by Inyo, on the south by Kern, and on the west by Kings County. It has an area of 4856 square miles, and the population is 59,0.'U (1920 census). The western half of the county lies in the San Joaf|uin Valley, and the eastern half is in the Sierra Nevada, culminating in a number of peaks along the summit at elevations exceeding 14,000 feet above sea level. The rocks in the mountains are mainly granites and other ])lu- tonics, whereas the valley is covered with Quaternary sediments. Vari- ous metamorphic and sedimentary rocks are found in the foothills. Climatic, soil and water conditions in the foothills and in the San Joaquin Valley section of the county are especially favorable to the growth of citrus fruits. This and other agricultural pursuits, includ- ing stock raising and dairying, are the principal industries of the county. The mineral resources of the county include brick, clay, copper, feld- spar, graphite, gems, limestone, magnesite, marble, quartz, glas.s-sand, soapstone, miscellaneous stone, and zinc. The commercial mineral products are brick, granite, lime, limestone, magnesite, natural gas, and miscellaneous stone, of which magnesite and granite are the most important. Clay Resources. Common clay of good quality for the manufacture of red-burned structural ware is plentiful in the valley and foothill section of the county. One brickyard has been in operation for a number of years. A deposit of buft'-bui-ning refractory clay has been found eight miles southeast of Ducor, but has not been developed commercially. See under Sears Clay Deposit. 'Clay-Worker, August, 1926, p. 131. 232 DIVISION OF MINES AND MINING Sears Clay Deposit. W. A. Sears, of Porterville, owner. Eight miles southeast of Diicor, in Sees. 26, 27, 35, T. 24 S., R. 28 E., M. D. M. This locality was visited in September, 1925, but the author was unable to meet Mr. Sears, or to find the deposit by personal search or by inquiry among residents in the locality. Later, ^Ir. Sears sent a number of samples of clav from the property. These were tested under numbers 283-A, 283-B, 284, and 285. See pages 314, 316, and 282. A descrip- tion of the deposit was given in Preliminary Report No. 7, p. 100, and is quoted below : "The clay bearing strata extend about one-half mile south of White River and about two miles in length along the south bank of the river. An overburden of gravel and clay 6 to 8 feet thick overlies a bed of white and blue plastic clay. A number of small cuts have been made along the south bank of the river. These pits show a white clay 6 to 8 feet thick overlying a blue plastic clay. The strata of clay beds have a general northwest strike. The development of this deposit has been only superficial, so the depth of the clay bed has not been determined. The clay is suitable for tile, sewer pipe, fire brick, vitrified brick and terra cotta." 8. P. Brick and Tile Co. W. D. Trewhitt, president ; H. W. Shields, secretary-treasurer ; H. G. Hayes, superintendent. General office. 435 Rowell Building, Fresno. The plant is three-quarters of a mile south of Exeter, in Sec. 14, T. 19 S., R. 26 E., M. D. M. The property com- prises 20 acres, all of which is underlain by workable clay to a depth of 12 to 18 ft., underlain by coarse gravel. The products of the plant are common brick and hollow tile. The clay is mined by a i-yd. electric shovel, having a capacity of 200 tons per eight hours. The clay is passed through a roll disinte- grator, from which it is elevated, screened, and passed to an American pug-mill and auger machine, eciuipped with a Freese cutter. Some of the ware is dried under sheds, and some in a waste-heat drier. The drying sheds have a capacity of 550,000 brick, and drying is usually completed in three weeks. The waste-heat drier has a capacity of 135,000 brick, and the drying period is three days. The brick and tile are tired in open-field kilns. The fuel is oil, atomized with steam. The firing period is 5i days, and the kiln turn- over cycle is 12 days. Two round down-draft kilns are available, but are not used, as they are more expensive to operate than the field kilns. The capacity of the plant is 8,000,000 brick, or the equivalent volume of brick and hollow tile, per year. Valencia Heights Shale Deposit. C. H. Weed, of Porterville, owner. The deposit is six miles east of Porterville. in Sec. 34, T. 21 S., R. 28 E., M. D. M., and consists of black clay shale, almost a slate. The shale is 1500 to 2000 feet in width, and cuts through a serpentine belt. The strike of the beds is northwest and the dip is 75° SE. Sample No. 206 was taken from a road cut, 5.3 miles from Porterville. The test results are on page 327. Bibl: State Min. Bur. Prel. Rept. 7, p. 101. Former Operations. The Pioneer Brick Company and the ]\IcKnight Firebrick Company, mentioned in Preliminary Report No. 7, pp. 100-101, are out of business. CLAY RESOURCES AND CERAMIC INDUSTRY 233 VENTURA COUNTY. General Features.' Ventura County is bounded on tlie north by Kern County, on tlie east by Los Angeles County, on the south by Los Angeles County and the Pacific Ocean, and on the west by Santa Barbara County. The total area is 1878 square miles. The population as shown by the census of 1920 was 28,724. The city of Ventura, originally called San Buenaventura, is the county seat, and is located on the shores of the Santa Barbara Channel. The cities of Oxnard, Santa Paula, and Fillmore are next in importance. Ventura County is essentially an agricultural and stock-raising county. The increasing ])roduction of petroleum in the i)a.st few years, however, is rapidly bringing it forward on the list of mineral-producing counties. The northern portion of the county is characterized by the converg- ence of several important mountain ranges, which make of it a high and rugged region. The moi'e mountainous and rugged parts of Pine Moun- tain and Topatopa Mountain form what is considered one of the rough- est and most inaccessible regions in California. Its lofty peaks range in elevation from 6000 to 9000 feet. To the northwest extend the San Emigdio Mountains, which form the connection between the Coast Range and the Sierra Nevada Mountains. To the west extend the San Rafael Mountains, while farther southward the Santa Ynez Mountains diverge from this group, running westward through Santa Barbara County. The southern part of the county is characterized by a series of ]iarallel folds, the axes of which lie east and west, forming low moun- tain ranges of no great continuity. The principal valleys are Santa Clara, Ojai, Simi, and Las Posas. The two principal drainage systems of the county are the Santa Clara River and the Ventura River. Next in importance, but sub- ordinate to these is Calleguas Creek, which drains the Simi and Las Posas valleys. The county is traversed by the Southern Pacific railroad, with a branch line from Ventura to Ojai. At Montalvo, five miles east of Ventura, the main line divides into two branches, one going to Los Angeles via Las Posas and Simi valleys, the other through the Santa Clara Valley, joining the San Joaquin Valley line at Saugus. With the exception of the higher mountainous areas, the county is easily accessible by roads, the main arteries being paved. Access to the gold and borax districts is obtained over the state highway from Bakersfield to Los Angeles via Tejon Pass. Mineral Resources. Ventura was the fourth county in the state in respect to the value of its mineral production in 1926. Petroleum and natural gas are the principal products. The only other products, in 1926, were miscel- laneous stone, brick, and clay. Undeveloped resources include asphalt, borax, diatomite, gypsum, limestone, mineral water, mineral paint, molding sand, phosphates, and sandstone. ' From Tucker, W. Burling, Ventura County : State Mineralogist's Report. XXI, pp. 223-225, 1925. 234 DIVISION OF MINES AND MINING Geology. The rocks of the Ventura rejiion fall into three classes : a meta- morphic aud granite complex, which is commonly referred to as the 'basement' complex, a series of sedimentary rocks, and a series of igneous extrusive and intrusive rocks. The metamor])hic rocks are all of ])re-Jurassic age and have been intruded by granite that is probably of the same age as that of the Sierra Nevada, which is considered to be late Jurassic or early Cretaceous. The sedimentary rocks, which in this region form the greater per- centage, range in age from Ui)i>er Cretaceous to Recent. The igneous rocks are practically all of Miocene age and are mainly andesite, dacite, basalt, andesite breccia, and associated mud flows. Clay Resources- Common clays are sufficiently abundant in Ventura County to serve all purposes. Two brickyards are operated as needed to supply the local market. No high-grade clays have been reported in the county. Anderson and Hardison. This is a common brick ])lant, 2.7 miles north of Santa Paula, on the Ojai Valley road. The clay is obtained from an extensive deposit of sandy clay and is mined by a tractor- drawn scraper. The clay is prepared by crushing and screening, and the brick are .shaped by dry pressing. So far as known, this is the only brickyard in California using the dry-press process of making common brick. Gas-fired field kilns are used. Sample No. 6 was taken for testing. The results are on page 389. Bibl: State Mineralogist's Kept. XXT, p. 237. People's Lumber Company. C. E. Bonistell, general manager. Office in Ventura. Clay pit and brickyard on the Ventura Avenue road, two miles north of Ventura. The clay is mined from an extensive deposit of Pliocene (Fernando ?) age, which is also utilized as an oil-well mud. Two varieties of clay are found : a yellow clay, .sample No. 4, p. 338, which is considered best for use in making brick, and a bluish clay, sample No. 5, p. 339, which is more fine-grained and plastic, and is especially desirable for use in the oil fields. Common brick, red ruffled brick, drain tile, roofing tile, and hollow building tile are made, by the stiff-mud ])rocess. Open field kilns are used for firing, and natural gas is available as fuel. Bibl: State Mineralogist's Repts. XV, p. 759, and XXI, pp. 236- 238. Bull. 38, p. 259 ; Prel. Rept. 7, pp. 101-102. YOLO COUNTY. General Features. Yolo County is in the Sacramento Valley, bounded by Sutter on the east and Colusa on the north. Its area i.s 1014 square miles, and the population is 17,105 (1920 census). The western edge of the county is in the foothills of the Coast Range, and the rest of the county is in the basin of the Sacramento River. The only commercial mineral resource at pre.sent is miscellaneous CLAY RESOURCES AND CERAMIC INDUSTRY 235 stone. Quieksilver was at one time produced. Deposits of iron and sandstone have been noted. Clay Resources. Common hi-ick clay is abundant near Winters, Woodland, and Capay. Small (juantities of brick Avere made, chiefly at Woodland and Winters, ill the eighties, usinji' deposits of clay and clayey k)ara. Bibl: State Mineralooist's Kept. X, p. 791; XIV, p. 367. State Min. Bur. Bull. 38, p. 25!) ; Brel. Kept. 7, p. 102. YUBA COUNTY. General Features. Yuba County lies in tlu^ north-central part of the state and borders the east side of the Feather Kiver. It is bounded on the northwest by Butte and Plumas counties, on the southeast by Placer and Nevada counties, and on the east by Sierra County. Its area is 625 square miles, and the i)opulation is 10,375 (1920 census). Since its boundaries extend from the floor of the central valley of California to the middle wester-n slope of the Sierra Nevada JMountains, Yuba County includes diversified topography and climate. Geology.' The general geology of Yuba County is similar to that in Nevada and Placer counties. The main central portion of the county consists gen- erally of gabbro-diorite and granodiorite, which in turn grade into metamoi-phic. amphibolitic rocks. Schists and slates in ])laces overlie the igneous rocks and arc intruded by serpentine in the northern part of the county. Alluvial sands and gravels cover the entire western portion of the county, while auriferous gravels, in i)laces, lie along the old channel courses. The areal geology of Yuba County has been covered by U. S. Geo- logical Survey Folios No. 17, 18 and" 43. Yuba County is still an imj^ortant producer of gold, which is recov- ered by dredging and hydraulic mining. Other mineral products are miscellaneous stone, silver, natural gas, and i)latinum. Clay Resources. High-grade clay in small quantities has been mined from the J. F. Dem]isey Kanch (see below) near Smartsville. Common clays suitable for tlie manufacture of red-burned structural ware are plentiful in the vicinity of IMarysville. Dempsey Ranch Kaolin Deposit. A. deposit of kaolin fire clay occurs on the ranch of J. F. Dempsey, in the E| of Sec. 3, T. 15 N., R. 6 E., M. D. M., 2 miles southeast from Smartsville. The clay occurs as irreg- ular bunches exposed in small chamber workings at the end of a 100- foot tunnel. The clay was evidently formed by the alteration in place of diabase or a similar intrusive rock which penetrates the serpentine mass of the hill in which the deposit occurs. The clay is badly con- taminated with limonitic iron in most of the exposed workings, but occasional bunches of 5 to 10 tons can be found that are quite free from 1 From State Mineralogist's Rept. XV, p. 420. 236 DIVISION OF MINES AND MINING iron. It is doubtful if a commercial quantity of white kaolin could be found. J. V. Chown of Oakland at one time held a lease on the property, and shipped 150 tons of kaolin for the manufacture of fire brick. The kaolin was found to be satisfactory' for this purpose, but on account of the isolation of the property, expensive mining, and the irregular occurrence of the clay, it was not possible to compete with other sources of material. The kaolin was hauled 20 miles to Marysville, over a rough road, at a cost of $5 per ton for haulage alone. 8ami)le No. 173 was taken for testing. The results are on i)age 313. Durst Ranch. One-half mile east of Wheatland. This locality was not visited, but a note on the occurrence of clay on this property was given in earlier reports as follows: "Shipments of clay were occa- sionally made, before 1905 ... to Gladding, McBean and Company at Lincoln. . . . The black clay loam used was 6 feet deep and over- lain by 18 inches of soil. Deposits similar to that on the Durst Ranch are abundant in the valley portion of Yuba County."^ Marysville Brick Company. This plant is a short distance north of Marysville, on the Feather River. A local surface clay is used for the manufacture of common brick. The plant was not visited and no details are available for publication. The production in 1925 was 1,100,000 brick.2 1 state MineraloRist's Rept. XV, p. 424, 1915-16, evidently abstracted from Bull. 38, p. 230, 1906. = Clay-Worker, February, 1926, p. 139. CLAY RESOURCES AND CERAMIC INDUSTRY 237 Chapter IV. CLAY TESTS AND THEIR INTERPRETATION AND THE CLASSIFICATION OF CLAYS. FIELD TESTS. While uo field tests of clays were made in preparing this report, tiie prospector or clay miner often wishes to deternune the possible eco- nomic value of clays before incurring the labor or expense of securing adequate samples and sending them to clay ])]ants oi' commercial labora- tories for testing. If samjjles are sent to clay plants it is usually neces- sary to send material to more than one plant, as a clay may be rejected by one operator as not being suitable for his ware or his plant routine, but this same clay may be eminenth' suitable in some other plant. The following sim[)le field tests for making a rough preliminary classification of clays, from the Third Report of the West Virginia Geological Survey, have been quoted many times, but are of such gen- eral interest to ])rospectors and others who are searching for clays in the field, that they are repeated here. 1. A small lump of clay may be roasted in the flame of a gas stove. If it turns red or brown, the percentage of iron is high, probably more than four per cent. 2. By tasting the clay, bitter salts, such as alum and epsom, may be detected, or such salts may occur a& white coatings on the outcrops of the clay in the bank. These salts are apt to form white wash coats on the finished brick, injuring their appearance. Sand may be detected by grit against the teeth. A rough idea of the percentage of such sand may thus be made. 3. A good idea of its plastic qualities may be obtained by working the moist clay with the fingers. A good test for pottery clay is to thus moisten it, and determine whether it can be worked into a definite shape, and whether or not it will retain its form when dry without cracking. 4. Shrinkage : A rough brick can easily be made and dried, and a good idea of the shrinkage arrived at. If it cracks or crumbles when dry or shrinks out of shape, its value is very doubtful. For this test, however, the clay should be ground thoroughly, tempered with water, and dried slowly. 5. If carbonates of lime are present, a few drops of hydrochloric acid will cause effervescence or bubbling, as the carbonic acid gas passes off. Very high percentages of lime are apt to ruin the clay. Good fire bricks are made of clay low in lime content. 6. The slaking of clays, or the crumbling down in tempering is tested by dropping a lump of clay in a cup of water. Some clays slake in a very few minutes, and so are easily tempered. 7. The color of a finished clay product is largely determined by the amount of iron present. It is not always possible to predict the color of the burned ware from the color of the clay. It is true that red clays will usually burn red, but blue clays or those of other shades also com- monly burn red or buff. The color of the raw clay is often due to organic matter which is combustible, and will be consumed in the burninor. 238 DIVISION OF MINES AND MINING While the above tests may not prove absolutely the quality of any fjiven elay, at the same time they furnish considerable valuable infor- mation in i-e^rard to it, and may be used to advantage by the owner of a deposit which has never been developed. If these simple tests seem to give ))ositive results it may then be well worth while to get in touch with buyers and consumers. LABORATORY TESTS. The methods of testing used for this report followed the standards or tentative standards of the American Ceramic Society,^ in so far as it was i)Ossible to do so with the ecpiipment and funds available. These methods or their equivalent have been followed in a number of recent state reports on clays.- Only such explanation of the testing methods and their inter])retation is given here as is necessary to an understanding of the text of this rei)ort and to indicate the divergences from the recommended methods. The reader is referred to the litera- ture for further details. Preparation of Samples. The weight of the sample collected in the field was usually a]i]iroxi- mately fifty pounds, but a number of them were smaller, owing to s]:)ecial difficulties of secnring proper samples or of transporting them. In sampling, the usual precautions were taken to secure material that was representative of the clay tluit would actually be mined. Notes on the macroscoi)ic character of the material sampled were made at the time of sampling, and are recorded in the description of the sam]ile. if of special interest. All foreign matter that normally would not be mixed with the elay, or that would be removed by screening before the clay is used in a elay-AAorking plant, was removed from the sample before shipment to the laboratory. In the laboratory, the entire sample was crushed to pass a 20-mesh screen, by passing through a laboratory jaw-crusher, followed by pass- ing through a set of rolls. One samjile, a flint fireclay (samjile Xo. 282), was further crushed in a pebble mill to develo}) maximum plasticity. Sufficient water was added to the ground clay to permit the mixture to be Avorked into a plastic condition. The attemi)t was made to main- tain a uniform consistency, so that all determinations of water of plasticity and drying shrinkage would be comparable, but with a series of clays of widely-varying plastic properties, it is impossible to attain a high degree of uniformity in the ])lastic state, without the use of more elaborate methods than the scope of the investigation warranted. After thoroughly working (wedging) the plastic mass, it was covered • Report of the Committee on Standards. American Ceramic Society, Reprint from Yearbook, 1921-22, Ohio State fniversity, Columbus, Ohio. Price fifty cents. - Wilson, Hewitt, The Clays and Shales of Washington, Their Technology and Uses, Bull. No. 18. University of "Washington, Engineering Experiment Station, Seattle, Washington, October, 1923. Skeels, F. H., and Wilson. Hewitt, Preliminary Report on the Clays of Idaho. Bull. No. 2, Department of Mines and Geology, Idaho, 1920. Parmelee, C. W., and Schroyer, C. R. Further Investigations of Illinois Fire Clays, Bull. No. 38, pp. 273-417. Illinois Geological Survey, 1922. Reis, H., The Clays of Kentucky, Ky. Geol. Surv. Series VI. Vol. 8, Frankfort, Ky., 1921. CLAY RESOURCES AND CERA^FTC TXDT'STRY 239 with wot sacking and seasoned foi- at least 24 hoiii-s before test pieces were i)repared. Test Pieces. The test pieces were shaped in l)rass molds, 1} in. by 1 J in. by 8 in., inside dimensions. Full lenoth bars were nsed for dry transverse- strength tests, and test i)ieees for drying and firing data were made by cutting the bars into four pieces. A minimum of four 8-in. bars and sixteen 2-in. test pieces were made for all important clays of which there was a sufficiently large sample. The i)lastic weight and volume of three test i)ieces were determined as soon as they were molded. All volume measurements were made in a Goodner mercury volumeter.^ Drying. The test pieces and bars Avere thoroughly air dried in the laboratory, then heated in an automatic electric oven for five hours at a tem])erature between 64= C. and 7G C. and finally at 105 to 110° C. for at least 12 hours. They were then transferred to a desiccator, where they remained until needed for dry weight and volume measurements, and for the dry transvei-se-strength test. Plastic and Drying Properties. Phisticihj : Notes on i)lasticity and molding properties were made at the time the test bars were molded. There is no satisfactory standard test or even a standard nomenclature to describe the plasticity of a clay in unambiguous terms. The term 'good ])lasticity' means a differ- ent condition to the common brick worker than it does to a stoneware worker. In general, the plasticity terms used in this report bear some i-elation to the ty]iical uses of the clay in question. The words 'short,' 'weak,' 'crumbly,' 'smooth,' and 'sticky' are used wherever they serve to clarify the meaning of tiie more general words 'poor,' 'fair,' 'good,' and 'excellent.' Some shales and indurated clays can be rendered more ])lastic by fine grinding.- The test data on such clays are of little value without l)articular reference to the preliminary preparation of the sample. Water of Phisficifii: The water of i)lasticity is tlie amount of water required to render a clay readily workable. It is calculated as a per- centage of the Aveight of the dry clay bar, according to the following formula : plastic wcifjht — dry weight Per cent water of plasticity = X 100 (1 I dry weisiit Shrinkage Waier: The water that is removed from a clay while it is shrinking from the pla.stic to the dry state is called the shrinkage water. It is calculated as follows: Plastic volume — dry volume Per cent shrinkage water = X 100 (2) dry weight ' Goodner, E. F., A Mercury Volumeter, Jour. Am. Cer. Soc. Vol. 4, p. 228, 1921. - Walker. T. C. The Effect of Fine Grinding on an Industrial Clay. Jour. Am. Cer. Soc, Vol. 10, p. 449, June. 1927. (A Southern California clay was used in this study.) See also the results on sample No. 2S2, this report, page 2S2. 240 DIVT^'O"' •" Ay "MINING Pore Wafer: Pore "vvater is that jiortion of tlie water of plasticity that is retained in the pores after shrinkage ceases. It is calculated as follows : Per fiMit iM)i(' w.iter ^ per cent water ol' plasticity — per cent shriukage water (8) Clays in which the percentage of shrinkage water is high may have excessive or sticky plasticity, and usually must be carefully dried to prevent warping or cracking. According to A. V. Bleininger/ the ratio of pore to shrinkage water shoidd not exceed 1.00 for bond clays, nor 0.75 for strong heavy plastic clays. Shrinkage : Drying shrinkage is most accurately determined by determining the volume shrinkage, then calculating the linear from the volume shrinkage. Volume shrinkage is calculated as follows, in per- centage of dry volume. plastic volume — dry volume Per cent dry volume shrinkage = X 100 (4) dry volume The linear drying shrinkage, in per cent of drj^ length, is calculated as follows: Calculated linear diying shrinkage = [,3/ drv volume shriukage f V 1 + . — 1 X lOU (5) 100 J In addition to calculated values of linear drying shrinkage, direct measurements were made by means of shrinkage marks on the 8-in. bars. These measurements are not reported, as they are inaccurate, and serve only as an approximate check on the calculated values. For many purposes, the drying shrinkage is expressed in per cent plastic volume or length. Either of these may be calculated from the data given in this rei)ort by means of the following formulas: Volume drying shrinkage, per cent plastic volume = volume drying shrinkage, per cent dry volume 100 + volume drying shrinkage, per cent dry volume Linear drying shrinkage, per cent plastic length = linear drying shrinkage, per cent dry length 100 + linear di\ving shrinkage, per cent dry length Linear drying shrinkage, per cent plastic length = X 100 (G) X 100 (7) - f/i vol. dry. shrink., % plastic vol. 100 X 100 (8) For convenience in making the large number of calculations for this report, tables of values were prepared for equations (5) and (8). As ■will be noted later, equation (8) is the proper form to use for the calculation of linear firing shrinkage, in per cent of dry volume. Dry Transverse Strength : The dry modulus of rupture was deter- mined on practically all of the clays tested. The 8-in. dried test bars ' Bleininger, A. V., Properties of American Bond Clays, etc., U. S. Bur. of Stand- ards, Tec. Paper No. 144, p. 51, 1920. CLAY RESOURCES AND CERAMIC INDUSTRY 241 "were of such a lenjjtli that one jl-in. Iji-cak and two ■^-'n\. breaks could be obtained on each bar. Tlie bars rested on ^-in. rollers, and the pull stirruj) also was efiuipped with a roller-bearing^ surface, so that the daufier of shear breaks was niinimized. Xo difference was noted in the average values obtained on the o-in. and the 8-in. breaks. At least ten breaks were made on all clays of which sufficient material was available for making the requisite number of test bars. A variation of plus or minus 15% from the average modulus of rupture was allowed, and at lea.st eight out of ten breaks came within these limits, unless noted in the text by tlie approxinuition symbol (zh). Where necessary, the tests were repeated until a set of consistent i-esults was obtained. The modulus of rupture is calculated by the following formula : Modulu.s of rupture, lb. per sq. in = 3 X breaking load in pounds X distance between supports in inches (9) 2 X breadth in inches X (deptii in inches )-' On the stroiiger clays, especially on the 3-in. breaks, it was necessary to use a lever Avith a ratio of 2.86. The lever ratio is multiplied by the breaking load to determine the breaking load at the point of application for use in equation (9). A nomogra{)]i was used to minimize tlie calculations involved. The following classification of clays by modulus of rupture is used in the text of this report : Metlium Medium Low low Medium hiffh High Modulus, lb. per sq. in to 100 100 to 200 200 to 400 400 to SOO above 800 This is the same classification as that suggested by "Watts ^ for bond- ing strength (q. v. below) and is an elaboration of that used by Parme- lee and Schroyer.- Bonding Strength: The modulus of rupture of dried bars containing equal parts of clay and standard Ottawa sand ■' is known as the bonding strength. It is of importance in all clays that are to be used with non- l)lastic material. A few bonding strength determinations w^ere made for this report. See samples No. 83, 273 and 280, pages 297, 273 and 305. It was intended to include more of tliese determinations, but it was found that to do so would unnecessarily delay the publication of this report. For an especially interesting comparison between dry modulus of rupture and 'bonding strength,' the reader is referred to the test results of Parmelee and Schroyer.* It will be noted that in some cases the bonding strength is higher than the dry modulus, but that in general the addition of 50% of sand to a clay lowers the trans- verse strength by 30% to 60%) of its original value. Fineness: The percentage of non-plastic material remaining on a 200-mesh (0.0029 in. ajierture) screen was determined for most of the clays tested. Fifty grams of the clay was taken, broken in a mortar and passed through a 10-mesh screen. The sample was placed in an 1 Watts, A. S., Classification of Clays on a Ceramic Basis. Jour. Am. Cer. Soc, Vol. 3, p. 247, 1920. 2 Parmelee, C. W., and Schroyer, C. R., op cit.. p. 293. ^Standard sand is sized between the limits of minus 20-mesh (0.0328 in. aperture) '•nd plus 2S-mesh (0.02."i2 in. aperture). It i.s used in the testing of cement. * Op. cit. 16 — 54979 242 DIVISION OP MINES AND MINING Erlenmever flask -with 150 ce. of distilled -water and 1 cc. of ammonia. The i)ul]) was thoi-ouglily shaken, let stand for 18 liours, and agitated for 10 minutes in a shalving machine such as that commonly used in the phosphorus determination in steel. The pulp was transferred to a 200-mesli screen, and all nndersize was -vvashod through the screen with a fine jet. The oversize was dried and weighed, and the result reported in per cent of plus 200-mesh material. Firing Properties. Firing Treatment : A test piece of each clay was fired to each alter- nate cone number from cone 010 to cone 13, except where insufficient Photo No. G7. Assay laboratory, Stanford University, showing nuitfle furnaces in which test pieces were lired. material was available to make enough test pieces for the complete series. In addition, most of the refractory clays were fired to cone 15. Denver Fire Cla.y Company oil-fired assay muffle furnaces were used for all firing from cone 010 to cone 13. These furnaces, shown on photo No. 67, were very satisfactory for the purpose, as the tempera- tures could be readily controlled, and since ten furnaces w^ere available, it was possible to place one or two sets of 30 samples in each muffle. If two sets of test pieces were placed in the same muffle, the set in the rear of the muffle was fired to two cones higher temperature than the set in the front, and the two sets were separated from each other by a full sized fire brick. This method of firing eliminated most of the trans- ferring of test pieces to a cooling furnace that is a disagreeable and CLAY RESOURCES AND CERAMIC INDUSTRY 243 unsatisfactory feature of most test Avork of this kind. The bottom tiers of test pieces were kept from contact with the muffle floor by placinj; tliom on .small fircchiv' saddh^s. Tlie fiiniaec tliat was used for firing to cones 11 and 1:5 was ('(juipped with a Carbofrax muffle, and with Carbofrax stools and muffle i)rotector plates. It was difficult to fire to these temperatures without flashing the test pieces. A Fisk ^ pre-mix ga.s-fired kiln was u.sed for firing to cone 15. This furnace, shoAvn on photo No. 68, has a 12-in. circular firing chamber, Photo No. 68. Fisk pre-mix gas-fired labora- tory kiln, in ceramic laboratory, Stanford University. This is used as a load and spall furnace and for firing tests to a maximum temperature of cone 30 (1650° C). All cone 15 tests were fired in this kiln. and is capable of accurate temperature control and good heat distribu- tion. The same furnace is used for load and spall tests of refractories, and is suitable for test work up to cone 30 (1650° C). Pyrometric Control: Temperatures were controlled with the aid of base-metal or preciou.s-metal thermocouples, in addition to Orton stand- ard pyrometric cones alongside the test pieces. The firing schedule ' Fisk, H. G., A Practical Gas-Fired Test Furnace for Plant Use. Jour. Am. Cer. Soc, Vol. 9, p. 151, March, 1926. 244 DIVISION OF MINES AND MINING was at a rate 50 '^f faster than the fastest schedule recommended by the American CVramic Society, aA'eraalling. Tlie results are reported to the nearest half-cone number, using the notation A-li {cj/., 31-;}2) to signify tliat tlu; softening i)oint lies nearer to A^ than to either A or B. Closer estimation, such as A — , A -|-, B — , or B -I-, was not considered to be justified by the limits of accuracy of the method itself, and leads to indefiniteness in that such notations might be read to signify 'less than' or 'greater than,' without setting the maximum or minimum range of the values as reported. 248 DIVISION OP MINES AND MINING For the purposes of tliis bulletin, all clays havinjj^ a softening point of cone 27 or higlier are classified as refractory, and those which fuse at cone 33 or above are considered to be highly refractory.^ Texture, Structure, and Hardness. Texture: Tlie texture of dried and fired test pieces is reported as fine-, medium-, or coarse-grained, depending upon the average size of the grains in the mass, and as close- or open-textured, depending upon the grading of the grains. This classification is nsed in order to permit a distinction betAveen those clays that may contain a large proportion of non-plastic grains that approximate uniform size, and those that contain clay and graded non-pla.stic grains in .such propor- tions as to give a closely knit, dense texture. Structure: The structure of fired test ])ieces is rei)ortefl as granular, stony, homogenous (with textural (|ualifications), or heterogeneous (with textural qnalifications). The soundness of a fired test piece is indicated by such terms as sound, hair-cracked (the development of Avhat many ceramic Avorkers term 'crow-feet'), shattered, or as cnn- taining one or more .small or large cracks. Hardness: The hardness of the fired test pieces is reported as greater or less than finger-nail (== 2| in ]\Ioh's scale) or steel (= 5i in Moh's scale). The hardness of dried clays is reported as very soft, soft, medium, equal to the finger-nail, or greater than the finger-nail. Color. The natural and fired colors of clays and ceramic products are too often expressed in indefinite terms that can not be duplicated by other investigators. Since the fired color of a clay or clay mixture is one of its mo.st important properties, some standard scale of colors should be used. For that reason, more attention is ])ai(l in this work to an accurate designation of color than is customary in similar publications. AVhile the colors obtained under laboratory firing conditions are not exactly the same for each firing temjierature as Avould be obtained in commer- cial kilns, the color possibilities of a given clay are clearly indicated by the laboratory tests. The two princi])al standard color scales in use in the TTnited States ai'e the Ridgway- and the ^lunsell'' systems.* For reasons hereafter noted, the Ridgway system is used in this bulletin. Since this is, so far as is known, the first time that either system has been used in a bulle- tin of this nature, a brief explanation of color terms and of each of the systems is given, together with an approximate correlation of parts of the two systems with each other. To adequately express a color, three variables must be used :^ (1) Hue, or the series of spectrum colors and their intermediates, through ' Parmelee, C. W., and Schroyer, C. R., op. cit., p. 281. = "Color Standards and Color Nomenclature." by Robert Ridgway. I'ublished by A. Hoen and Company, Baltimore, Maryland, l!n2. Price $12. ■■"'A Color Notation." bv A. H. Munsell, Tth edition. 1920 (price $2), and "Atlas of the Mun.sell System," 1915 (price $25), both published l)y the Munsell Color Company, Baltinioi'e, Maryland. ■• Lenchner. Theodor, "A Study of Color and Its Appplication to Ceramic Art." Jour. Amer. Cer. Soc, Vol. 10, p. 538, July, 1927. in which a combination of the Munsell and the Prang (an earlier work) systems is proposed. ^ In preparing this paragraph, Munsell's "A Color Notation" was freely drawn upon. CLAY RESOURCES AND ( EKAMIC INDUSTRY 240 red. ormifre, yellow, jrreen, Miic and violet. Hue can be accurately expres.sed by detenniiiiiijr tlie wave jenji'th of tbe lip-bt waves of each color sensation. (2) Tone or value, by which a lijrlit color is distiu- g-uished from a dark one. When white is added to a color, various tints result, and when black is added, the shades are in-oduced. Tone can be measured by nutans of a photometer, and is ex])ressed scientifically in terms of the amplitude of the light waves reflected by the color. (8) Chroma, by whieh stronjr colors are distinguished from weak ones. It is the effect ])roduced by addingf neutral g:ray to a hue of any given tone. Scientifically, it is the purity of one wave leng-th sei)arated from all others. Ridgwafi Color S^tanfhird.'i: The key to the Ridgway classification consists of 36 hues, which include the six fundamental spectrum colors, red, orange, yellow, grreen, blue, and violet, which are connected by intermediate hues. The chromatic scale forms the horizontal line of the entire series of charts. The vertical scale on all charts, except the carbon-gray series, represents the tone (Munsell's "value") or lumi- nosity. That is, the proportion of black or white which is mixed with the full color. The first series of Ridgway's plates contains the pure colors. This .series is repeated five times with successively increasing amounts of neutral gray, but with some hues omitted in the last three series. These series are designated "broken color scales" by Ridgw^ay, but Munsell's term "chroma" is to be ])referred. The complete designation of a color from Ridgway's charts therefore involves the use of three symbols: (1) an arable numeral to designate the hue; (2) the superscript (' to ' ' ' ' ') to indicate the chroma; and (3) a loAver-case letter to designate the tone (or value). Thus, o'k is a hue containing 60'';/ red and 40% orange, shaded with 70.5% of black, and the Avhole mixed with 32% of neutral gray. The result is a brick red. It is possible to interpolate between the Ridgway colors whenever an exact match can not be found, and the.se can be designated by the alternate symbols that are omitted from the color charts. No attempt was made to exi)ress the clay colors in this bulletin closer than the nearest Ridgway number. Expressed in common color names, the Ridgway hues 1, 3, 5 and 7 either of tone "b" or unaltered as to tone, are "red"; 9, 11, 13 and 15 of the same tones are "orange"; and 17, 19, 21 and 23 of the .same tones are "yellow." Colors that would be classed as "pale" or "verv light" are of tone "f." "Pink," "light orange," "light yellow," "huff," etc., are tone "d." The "i" tones, as well as the "k" tones in hues 1, 3 and 5, are those that would be designated as "dark." The "k" tones, except in hues 1, 3 and 5, are "browns"; for example, "red- brown. " ' The " m " tones are ' ' dark-browns. ' ' With respect to chroma, the pure spectrum series is purer than will be foimd in most ceramic products, although many glazes fall into this class. The (') series includes most glazes, especially matt glazes, as well as the more bril- liantly colored red- and pink-burning bodies. The (") series includes the greater poi-tion of all pink-, buff-, and red-burned clay products. The ('") series includes colors that are generally too dull for artistic purposes. The ("") and the ('"") series are decided grays, of little interest in decorative wares. 250 DIVISION OF MINES AND MINING Munsell Color Stancla)-ch: The Munsell system uses the conception of a sphere to evaluate the tliree eoh)r constants. Each of the con- stants is theoretically divided into ten equal parts. Hue is the hori- zontal scale around the circumference of the sphere, and is designated by an upper-case letter represent ing an abbreviation of the color, as red (R), yellow-red (YR), Yellow (Y), etc. These letters are pre- ceded by a numeral from 1 to 9 to represent the position of the color in the scale of hues. For exami)le, ".IR" is the ''middle hue" of red. These symbols are followed by a fraction, the numerator of which designates the value and the denominator of which designates the chroma. "Value" is represented as the vertical axis of the color sphere, with white (value 10) at the top and black (value 0) at the bottom, but samples are shown only for values 2 to 9, inclusive. "Chroma" is traced by radii at right angles to the vertical axis of the spliere. An approximation of Ridgway's 5'k is given in the Munsell system as 7R 3/7 but the nearest color actually shown on the charts is 5R 3/7, which lies between Ridgway's I'k and I'm. Ridgway vs. Munsell: The Ridgway system was chosen for this work in preference to the Munsell system for the following rea.sons: (1) Ridgway's s.ystera includes 1115 named and systematized colors, whereas the Munsell Atlas contains but 340 different colors, which, liowever, are completely duplicated in two different arrangements, and })artly duplicated in two other arrangements. (2) The Ridgway system has 36 colors in the scale of hues, whereas the Munsell system presents but 10 different hues. Each system uses the same number of subdivisions in the scale of tone. While the Munsell system provides for a maximum of 10 divisions of chroma compared to 6 for the Ridgway charts, not all of these divisions are used on all tones and hues in either system and the average chroma scale has approximately the same number of divisions in each system. As noted by by Lenchner ^ the Munsell system would be greatly improved by the addition of more hues. (3) The Ridgway charts are bound in an octavo book, of a]>proximately one-third the bulk and weight of the IMunsell Atlas, yet each color has an area of 0.5 sq. in., compared to 0.4 sq. in., and the minimum space between each color sample is \ inch, compared to -^ inch on the Munsell charts. These are important factors influencing the efficiency of use of the two systems for the purpose of matching colors. The charts in either system may be removed from the book, and mounted side by side on a wall or table, preferably under glass. In this case, the Ridgeway charts occupy a minimum space of 10.3 sq. ft., and the Munsell charts occupy 11.2 sq. ft. When so arranged, the Ridgway system still possesses a distinct advantage in the time required to match a color and record it accurately. (4) All of the Ridgway colors are named, as well as numbered. This is frequently of value in preparing written descriptions, and for other purposes. (5) The Ridgway system costs less than half as much as tlie Munsell system, and there is no difference in tlie life of the colors when exposed to light, lience replacements of RidgAvay's charts can be made more cheaply when the colors have faded. A tabulation of the Ridgway colors most frequently used in this report is given in Table No. 10, with an approximation of the corres- » Ov- cit. CLAY RESOURCES AND CERAMIC INDITSTRY 251 poiiilinji- Muiisell color. This comparison was made visually by three persons ' indei)endentl3% and average values are reported. This correla- tion makes no claim to scientific accuracy but a])iiroximates the result that would be obtained by the average user of either set of charts. TABLE No. 10. Visual Correlation of Certain Ridgway Colors with Munsell Colors. Approximate Uidgway Munsell .syml)ol equivalent Ai)prt)ximate Ai)i)ioximat Ridgwa> Munsell Ridgway Munsell symbol etiuiv ilent symbol equiv ilent 5'i 7R 5/9 3"d IR 7/4 k 7R 3/7 b 4R 6/5 m 6R 3/4 3R 5/7 7'f 7R 8/4 i 5R 4/5 d 8R 7/6 5"f 3R 7/3 b 8R 6/8 d 5R 7/4 9R 5/8 b 5R 6/5 1 9R 4/7 _ 5R 5/7 k 9R 4/6 i 7R 4/5 m 7R 3/4 k 7R 3/4 9'f 8R 8/4 m 7R 3/3 d 9R 7/5 7" f 6R 8/3 b lYR 6/7 d 7R 7/4 lYR 6/8 b 9R 6/5 ~i 2YR 5/7 9R 5/7 k lYR 5/7 i 9R 4/5 m 9R 3/4 k 9R 4/4 ll'f 9R 8/4 m 8R 3/4 d SYR 8/r, 9"f 6R 8/4 b SYR 7/7 d 9R 7>6 SYR 6/8 b 9R 6/5 1 SYR 5/7 9R 5/6 k 4YR 4/5 i 1YR 5/5 m SYR 3/5 k lYR 4/3 13'f 5YR 8/5 m lYR 3/4 d SYR 8/5 n"f 7R 8/3 b SYR 7/7 d 2YR 7/5 15'f 4YR 8/5 b lYR 6/6 d 6YR 7/7 _ lYR 5/6 1) 7YR 7/8 i 2YR 5/6 17'f 7YR 8/5 lS"f 9R 8/3 d 7YR 8/5 d SYR 8/5 b ttYR 7/8 b SYR 7/7 19'f 5Y 8/6 j SYR SYR 6/6 5/6 l"f 2R 7/3 ir,"f 9R 8/4 d 8RP 7/4 d 4YR 8/5 b IR 7/5 b SYR 6/6 3R 5/5 4YR 6/6 3"f 3R 7/3 i 5YR 5/5 17"f 2YR 8/4 d GYR 8/4 b 7YR 7/7 _ 7YR 6/5 i 7YR 5/5 19"f 7YR 8/3 d 9YR 8/5 b 9YR 7/7 9YR 6/7 1 9YR 5/6 l"'f 6RP 8/2 d 6RP 7/4 b 9RP 6/4 5"'f 9RP 8/2 d 9RP 7/3 b 3R 6/4 3R 5/4 i 3R 4/4 9"'f 4R 8/2 d 4R 8/2 b 4R 6/4 6R 5/4 i 8R 4/4 k 8R 3/4 lS"'f 5R 8/1 d 5R 8/2 b 7R 7/3 lYR 5/4 1 2YR 4/4 k 3YR 4/3 17"'f SYR 8/2 fl SYR 7/3 b 4YR 6/3 7YR 6/3 i 7YR 5/3 k SYR 4/2 L'l"'f 4Y 8/2 d 6Y 8/3 Color Classification of Clays: The clays desci'ibed in this report are classified as to color into four groups, following Parmelee and Schroyer," but definitely fixing the boundaries of each group by the use of Ridg- way 's colors. The classification is as follows: I. Clays Burning White or Cream Colored, not Calcareous. Into this group are placed all clays that fire at the highest firing tempera- tures used, to tones nearer to white than Ridgway 's "f " tones. There is need for an extension of standard color nomenclature into this range," but in lieu of a well-established system, the terms "yellowish- white," "pinkish-white," "grayish-white," etc., are used in this report. All of the clays in this group lire to colors that are sufficiently good to permit the use of the clay in stoneware bodies, most of them can be used to some extent in sanitary ware and electrical porcelain, if other 1 Prof. F. G. Tickell, Stanford University, Mrs. Bernice L. Tickell, and the author. = Parmlee, C. W., and Sohroyer, C. R., "Further Investigations of Ulinoi.s Fire Clays," 111. Geol. Surv. Bull. No. 38, p. 278. ' See in this connection : Lofton, R. E., A Measure of the Color Characteristics of WHiite Papers, U. S. Bur. Std. Tech. Paper 244, 192S. 252 DIVISION OF MINES AND MINING properties are suitable, and a few are -\vliite enoii ; do not seriously overburn for 12 cones higher; highly refractory; softening point at cone :il or higher; bending strength minimum 325 pounds per square inch. Use: Graphite crucibles for melting brass, "fl. Non-porous at about 1275° C. (cone 8), not overflring at 1400° C. or higher. Strength and softening point as alaove. Use : Steel crucibles. "10. Become dense at about 1275° C. (cone 8). Do not overburn below 1425° C. Bonding strength, 250 pounds per square inch or higher. Softening point, cone 29 or higher. Use : Glass pots." II. BUFF-BURNING CLAYS. A. Refractory clays (softening point, cone 27 or above). a. Open-burning, i.e., having a porosity of 6% or more at cone 15. Parmelee states ". . . porosity of 5% or more at cone 15 or above." 5. Low strength. Usually higli in non-])lastic material. 6. ]Medium and high strength. Parmelee uses four subdivisions to cover (5) and (6) as follows: "Indurated — non-plastic or slightly plastic unless it lias been weathered. Type : Flint clay. "11. Normally aluminous; maximum alumina 40%. Uses: Refractories. "12. Highly aluminous; alumina exceeds 40%. Type: Diaspore clay. Uses; Refractories, abrasives. Plastic. "13. Normally siliceous; maximum silica not exceeding 65%. Uses: Firebrick and other refractory wares, terra cotta, sanitary ware, glazed and enameled brick (see specific requirements). "14. Siliceous; having a silica content above 659^. Type: Many of the New Jersey Are clays. Uses : Firebrick and other refractories." b. Dense-burning between cones 10 and 15, i.e., attaining an appar- ent porosity of 6% or less within that range. Parmelee states "... a minimum porosity of 5% or less . . ." 7. Generally medium to high strength. This is Parmelee 's class 15, and is explained as follows: "15. Medium to high strength. Do not overburn for 5 cones higher than point of minimum porosity. Uses : Glass pots and other refractories ; al.so used for firebrick, saggers and miscellaneous refractories, architectural terra cotta, sanitary ware, enameled and face brick." e. Den.se-burning, i.e., attaining a porosity of 6% or less at cone 10 or lower. Parmelee states "... a porosity of 5% or less . . ." 8. Generally medium to high strength. Parmelee divides this grouj) into three classes, as follows : "16. See (Parmelee's) 8. CLAY RESOURCES AND CERAMIC INDUSTRY 255 "17. See (Parnielee's) 9. "18. See (Tarmelee's) 10. "These tliree classes, 10, 17 and 18, are used also for ziiie retorts, firebrick, saggers, and miscellaneous refractories, architectural terra cotta, sani- tary ware, enameled and face brick." B. Xon-refrac'tory clays. a. Open-bnrniiijr, i.e., do not attain a porosity of fi'^J or less at any cone lower tlian cone 10. rarmelee states "... a porosity of 5'/^ or less !i. lli<.>-h or medium streiioth. Uses: Architectural terra cotta, stoneware, yellow ware, face brick, sanitary ware. 10. Low strength. Use : Brick. ' Classes (fl) and (10) correspond to Parnielee's 19 and 20, respectively. b. Dense-burning, i.e., attain an ajiparent ])orosity of less than 6% at cones lower than 10. Parmelee states "... a porosity of les.s than 5% . . ." 11. Generally medium or high strength. This is Parnielee's class 21, and is described as follows: "21. High or medium strength. Uses: Architectural terra cotta, stoneware, abrasive wheels, sanitary ware, face brick, paving brick." III. CLAYS BURNING RED, BROWN, OR OTHER DARK COLORS. A. Open-burning clays, i.e., those that do not attain an apparent i)or- osity of 6% or less at any temperature short of bloating or fusion. Parmelee states ". . . do not attain low porosity at any temperature short of actual fusion." 12. ]\ledium or high strength. Uses: Brick, drain tile, hollow blocks, flower pots, pencil clays, ballast. 1.3. Low strength. Use: Brick. Classes (12) and (13) correspond to Parnielee's 22 and 23, respectively. B. Dense-burning clays, i.e., those that attain an apparent jiorosity of 6% or less at any temperature short of bloating or fusion. Parmelee makes no special statement to qualify the meaning of "Dense burning," but the definition follows from IIT-A, above. a. Having a long vitrification range (4 cones). Parmelee requires a 5-cone vitrification range, but the data of this bulletin do not permit such a .segregation, as only alternate cone num- bers were studied. 14. Generally medium or high strength. Uses, if medium or high strength : Conduits, sewer pipe, face brick, roofing tile, paving brick, promenade tile, architectural terra cotta, and similar ware. If low strength: Common brick, floor tile, dust body in various wares. 256 DIVISION OF MINES AND MINING Parmeloo makes two classes, 24 and 25, divided as to medium to hif?h strength or low strength, with the uses practically as indicated above. b. Having a short vitrification range (less than -i cones). 15. Generally medium to high strength. Uses: Common brick, face brick, hollow tile, flower pots. Tliis is Parmelee's class 26, described as "High or medium strength," witii the same uses as given above. c. Fusing at a low temjjeraturc, api)roximately cone 5, to foi-m a glass. &^ 16. Slip clays. This is Parmelee's class 27. No clays were found in California in this class, but room is left in the classification in case any are found in the future. IV CLAYS BURNING DIRTY WHITE, CREAM WHITE, OR YELLOWISH WHITE. 17. Generally containing calcium or magnesium carbonate or both. Seldom reach very low porosity. Have a very short heat range. Use : Common brick, or may be worthless. This is essentially Parmelee 's class 28, which is described as follows : "28. Containing calcium or magnesium carbonate or both. Never reach very low porosity. Have a very short heat range. Use : Common brick." The foregoing classification is not presented as being preferable for general use to Parmelee's more complete one, but it serves the i)ur- poses of this bulletin better, in that the tests on the California clays were not sufficiently comprehensive to permit the degree of refinement of clay classification that characterizes Parmelee and Schroyer's report. For example, bonding-strength determinations are necessary in order to segregate Parmelee's classes 8, 9 and 10, and 16, 17 and 18; firing tests to cone 19 or 20 are necessary to fully determine the properties of a clay for his classes 5, 8 and 16 ; chemical analj^ses are necessary in order to segregate his classes 11, 12, 13 and 14, and firing to each cone number, instead of to alternate cone numbers, is required in order to separate the red-burning clays having a long vitrification range from those having a short range. To complete the data for a satisfactory allocation of clays according to Parmelee's classification, would have required more than twice the amount of work than that represented by the testing for this bulletin, without considering the extra field work that should be entailed to secure thoroughly representatiA'e samples of entire clay beds. It is questionable if 50-pound field samples, unless obtained by quartering down a number of larger channel-cut samples, or by combining a number of coredrill samples, are sufficiently reliable to warrant more elaborate tests than have been made. »i-.T:in i -NTl-* /ir-D A HTK' T M HT T>iTR V Ji'^l ed. The :'y trans- he clays ord IJiii- 11(1 dried v'ho ^vish ew clays )spectin The Clays and Shales of W'ashington, Their Technology and Uses. Bull. Univ. of Wash., Engin. Exp. Sta., No. IS, p. 20.3, ct seq. 17—54979 258 DIVISION OP MINES AND MINING « c CO '— '-0 »c ^ cc tf; CI -*< *t" •-■ — ' ;D O -.^ ^^ ^« r-< _ c>l C^l C^l 7-1 C-i ^- d ci t^ C-) ci -r i^ oo 00 o o ^- ^H O 1^ (M C-1 ^- ^- OO 00 CO I ^ C-1 CC t^ C5 ^- »0 •— -- ^ « C-1 iiMcoffO-^':o^r-oO'— • — — — li^t^i-oocxioocio — — — Ti»co _H ^^ *-^ .-^ _ .^ _. *_ -^ ^« _ ^H ^H l^) c-i rt ci C) 'M C4 E PQ CQ -^ I ■to + s O •—''—' 1—1 (M C-l C-1 6 ^ CiiC^-^iOOi-^tCOOCrcOiCCCCO ,_ ^H — 1— . ,— . (M C-l (M -f P:i Q o C*IfMCO'^TfiO»CW5b-0»000 O S «^ ^ bC co05X)Oc*3»C'— ■oroc;co'-0't'^^-t-^oooooiOiOOc*:^co■^lCC:>l^•cco:d- .-H(Mi:o^t^t^t^r^oooooc^ico-^-^'^o;C5ecc*3co-^»(^t--oooo If? CO o !M "^ Tt< ^ -^ (M PQ « + \ ocooo 0-* eo t^ C5 Oi W -^ t^ ^ <— "CM C ^ ^ « '-•Mr-OOClCO'^'— 'CCOOCi-^CiOO^iCOOCTltC^r^CiOO .-,— icccocoococ;0'M(Mro»o:cdC. dOOcococo»o*.o ,„ _< ,_ .-4 .^ ^« ^M 1^ -« C^l CI (p. .")})). Aiiiadoi- County. lone. Sample sii|)plie(l by AVm. Haverstick. This is a sand containinp: a hi<>:her proportion of day than tlie more typical samples (see No. 128, 129 and 134), hence ))ossessiii«>' b(4ter pla.sticity and ai-eater shrinkap-o. The i-esidno on 2()()-mesh is 1.1.8 /^ . The color is ^^ood, bnt <>'reen scuniminji' is esi)e- cially noticable. Steel hardness is develo])ed at cone 9. The total linear shrinkage, ])lastic basis, at cone 1.") is lo.2%. The softening point is cone 32. No. 235 ()). 70). Calaveras Connty. Valley Springs. Texas Alining Comjtany. This is a kaolini/ed sei-icite-talc schist that has sufficient jdasticity to permit molding or pressing. The dry strength is low, and in the dried condition it is soft and friable. The colors are: dry, 17"f ; Avet, 15"d; cone 06 to 1, 13"f; cones 5 to 13, pinkish-white. Finger- nail hardness is developed at cone 1. The fired strnctnre is sonnd, weak, and fine granular. The total linear shrinkage, ])lastic basis, at cone 13, is 14.6'/f ■ The softening point is cone 30-31. The material could be used as a noni)lastic ingredient in white flooi- and wall tile. No.2S6{\^.m). Calaveras County. Nigger Hill. "Kaolin." This is an impure kaolin that has resulted from the alteration of a sericite- talc schist. The ])lasticity is fair, the dry strength is low, and in the dried condition it is soft, friable and fine-grained. The colors are: dry, nearly white; wet, grayish w^hite ; cones 06 to 13, nearly w^hite. Finger-nail hardness is developed at cone 06, and steel hardness at cone 5. The fired structure is sound, medium strong, and fine-granu- lar. The total linear shrinkage, ])lastic basis, at cone 13, is 20.9%. The softening ])oint is cone 29-30. The material can be used as a non- plastic ingredient in white tile bodies. No. 237 (p. 68). Calaveras County. Nigger Hill. Sericite-talc schist. This is similar to No. 235, but contains a slightly higher percent- age of iron. The total linear shrinkage, plastic basis, is 14.5% at cone 13. The .softening point is cone 27-28. No. 2'>9 (\). 45). Alameda County. Tesla. This is a white-buining fireclay with excellent ])lasticity and medium low dry strength. It contains 1.6% of -(-200-mesh sand. In the dried condition it is soft, fine-grained and close-textured. The colors are: dry, 17'"f ; wet, 15"f ; cones 010 to 04, ])inkish white; cones 02 to 9, nearly white; cones 11 to 15, yellowish white. Steel hardness is develo])ed at cone 3, and less than 10% absorption at cone 11. The fired structure is stony and smooth-textured. A few small cracks appear in some of the fired test pieces. Slight blistering is noted at cone 13. The total linear shrinkage, plastic basis, is 20.4% at cone 15. The softening point is cone 34-35. This is one of the best fireclays tested and if it can be found in com- mercial quantities, it wall undoubtedly be in great demand for fire- brick, whiteware, and tile. No. 268. This sample has already been described (see No. 63, p. 260) . 264 DIVISION OP MINES AND MINING 2. Medium to High Strength. No. 15 (p. 163). Riverside County. Alberhill C. & C. Co. "Select Main Tunnel." See also No. 13 (class 7) and 29. This clay is hand sorted from the main tunnel fireclay bed, in order to make a marketable grade that is intermediate in quality between the run-of-mine material (No. 29) and the extra-select main tunnel clay (No. 13). It is used principally in the manufacture of tire brick. It is fine-grained, with excellent plasticity, medium high dry strength, and good dry condition. It contains 11.3% of plus 200-mesh sand. The colors are: dry, 13"'f ; Avet. 17""b; fired, cream white, considerably whiter than Ridgway's "f " tone. Finger-nail hardness is developed below cone 010, and steel hardness is reached at cone 5. The total linear shrinkage, plastic basis, at cone 15 is 11.7%. The softening point is cone 30-31. The best firing range is from cone 5 to cone 15. No. 28 (p. 163). River.side County. Alberhill C. & C. Co. "SII-3." This is a clay with excellent plasticity, medium dry strength, and a fine grained, clo.se-textured dry condition. It contains 11.2% of -|-200- mesh sand. It is used for art title and architectural terra cotta. The colors are: dry, 13'"f; wet, 13'''d; cone 010 to cone 1, 17"f; cone 3 and above, the pink gives way to yellow, and the tone is nearer white than Ridgway's "f" tone. Finger-nail hardness is developed below cone 010, and steel hardness at cone 7. Vitrification is not well advanced at cone 13. The total linear slirinkage, plastic basis, at cone 13, is 10.0%. The softening point is cone 30. The best firing range is from cone 3 to cone 13 or above. If this clay were more plentiful, it would find a wide use in art title, terra cotta, and similar products. No. 29 (p. 163). Riverside County. Alberhill C. & C. Co. "Main Tunnel." See also No. 13 (class 7) and No. 15. This is the run-of-mine main tunnel fireclay, and differs from the selected varieties, No. 13 and No. 15, mainly in that it contains more sand and more coloring matter. The percentage remaining on 200-mesh is 37.2. The clay is widely used in fire brick, art title, architectural terra cotta, and for similar purposes. It has a good working plasticity, but the plastic strength is low. In the dry condition it is medium hard, with a coarse, open texture, and the dry strength is medium. The colors are: dry, 17"'f; wet, 17"'d; cones 010 to 04, 13"f ; cones 02 to 3, 13"'f ; cones 5 to 13. nearer white than 17'"f. Finger-nail hardness appears below cone 010, but steel hardness does not develop within the firing range of the tests. The total linear shrinkage, plastic basis, is 5.6%, at cone 15. The softening point is cone 30-31. The best firing range is from cone 5 to cone 15 and above. No. 44, 45 and 57 (p. 196 and p. 194). San Bernardino County. Hart. No. 44 is from the lower tunnel, and No. 45 is from the upper tunnel of the deposit owned by the Standard Sanitary Manufacturing Co., while No. 57 is from a similar deposit in the same district, owned by H. F. Coors. They are white-burning clays that may be classed as china- ball clays, as they possess the properties of a mixture of china and ball clays as usually used in porcelain and whiteware bodies. No. 44 con- tains more quartz than the other two samples. It contains 33.4% of +200-mesh material. No. 45 contains 28.2 ^( , and No. 57 contains 21.8%. All three samples contain a small proportion of undecomposed CLAY RESOURCES AND CERAMIC INDUSTRY 265 ferro-magncsiaii minerals, ^v}lich is readily removed in the usual processes of slip preparation. Enough colloidal iron is present in No. 44 and 45 to impart a yollowisli tint to the tired clay, hut No. 57 is the whitest clay that was tested, and has a distinctly better color tlian English china clay or Edjrar (Florida) kaolin. The plasticity of all three samples is excellent and the dry strength is exceptionally high. Finger-nail liardness is present in tlie dry state, and steel hardness develops at cone 06. Although the softening point is cone '-iO for No. 44 and 45, and cone 29 for No. 57, bloating begins at cone 11 to 13. The maximum total linear shrinkage, plastic basis, is 9.5% at cones 3 to 5 for No. 44. IG.O'r at cone 15 for No. 45, and 14.8% at cone 11 for No. 57. Small tiring cracks are found in some of the test pieces of No. 45, fired above cone 3, but all test pieces of No. 44 and 57 are sound. The tendency of these clays to bloat when used in porcelain bodies to be fired above cone 8 is their most serious defect, and has prevented their continued use in two sanitary ware plants that formerly used them in place of Eastern or English clays. No. 44 and 45 are now used in the enameling plant of the Standard Sanitary Manufacturing Co., and No. 57 is used in the manufacture of electrical and plumbing accessory porcelain, in tlie jjlant of the 11. F. Coors Co. The best firing range is from cone 06 to cone 8 to 11. No. 59. Edgai- kaolin (Florida), used by the American Encaustic Tiling Comi)any. This is a white-burning kaolin, with smooth and strong plasticity, medium dry strength, and a soft, fine grained, close-textured, dry condition. Some finely divided mica is ]-)resent, but the sample contains onl,y 0.6% of 4-200-mesh material. A faint pink color can be noted when fired below cone 1, but at higher temperatures the color closely approximates pure white. Finger-nail hardness is ohtaiiuMl below cone 010, and steel hardness develops at cone 3. The fired structure is stony, and with the firing schedule used, all test pieces had deep crow-foot cracks, which, however, were not continuous enough to cause disintegration. The total linear shrinkage, plastic basis, at cone 15 is 24.8%. The softening point is cone 34r-35. The best firing range is from cone 1 to above cone 15. -Vo. .W fp. 171). Riverside Countv. Alberhill. G.. McB. & Co. "Main Tunnel Fire Clay." This should be compared with No. 13 and 229 (class 7), 15, 29, 84 (class 6), 91 (class 1), and 93, post. No. 90 con- tains 17.4% of +200-mesh sand. The plasticity is excellent, the dry stre?igth is medium, and in the dri(Ml conditiou it is medium hard, fine grained and close-textured. The colors are: dry, 17""d; wet, neutral gray k; cones 010 to 13, pinkish white, changing at the higher tempera- tures to yellowish white. Finger-nail hardness is developed below cone 010, and steel hardness appears at cone 11. Tiie fire structure is sound and fine-granular. The total linear shrinkage, plastic basis, at cone 13, is 10.7%. The softening point is cone 31. No. 93 (p. 171). Riverside County. Alberhill. C, Mc.B. & Co. "Select Main Tunnel." The properties of this clay are almost identical with those of No. 90, except that it is finer-grained, has lower porosities, and the colors are slightly whiter throughout. The sample contains 1.0% of 4-200-mesh sand. Steel hardness is developed at cone 1. The total linear shrinkage, plastic basis, at cone 13, is 11.8%. The softening 266 DIVISION OF MINES AND MINING point is cone 80-31. It is a useful clay for terra cotta, faience tile, face brick and fire brick, and may be used in stoneware and pottery. No. 109 (p. 176). Riverside County. Alberliill. P. C. P. Co. "Doug- las ]\Iain Tunnel." This is from an extension of the formation from which the Alberliill Coal and Clay Company's "Main Tunnel" clays are mined, see No. 13 (class 7), lo, and 29, but is more closely related to the G., McB. Co. "Main Tunnel Fire Clay," No. 90, in its^ ceramic properties. It contains 22.6'/ of -|-200-mesh quartz sand, and a small proportion of ferro-magnesian minerals. Tlie plasticity is very good, and the dry strength is medium high. In the dried condition it is medium hard, and has a medium fine grain and close texture. The colors are: dry, 13"f; wet, 15"d ; cones 010 to 1, 7"d ; cone 3, 7"f ; cones 5 to 13, Avhiter than 17"f. Finger-nail hardness appears below cone 010, and steel hardness develops at cone 5. The fired .structure is sound and fine granular, with a slightly rough exterior. The total linear shrinkage, plastic basis, at cone 13, is 9.7%. The softening point is cone 30-31. The principal uses for this clay are for fire brick, face brick and stoneware. No. 137 (p. 57). Amador County, lone. M. J. Bacon. "Choc- olate." This is a plastic fire clay that is occasionally marketed as a sagger clay. It contains 7.0% of +200-mesh sand. The plasticity is excellent, the dry .strength is medium, and in the dried condition it is medium hard, fine-grained, and close-textured. The colors are : dry, 13"f; wet, 9"d ; cone 010, 13"f, fading to yellowish-white at cone 02, and continuing to cone 13 without appreciable change. Yel- low scumming is especially noticeable. Steel hardness is developed at cone 11. The fired structure is sound, fine-granular, and with a slightly roughened surface texture. The total linear shrinkage, plastic basis, at cone 15 is 16.2%. The softening point is cone 32. CLAY RESOURCES AND CERAMIC INDUSTRY 267 TABLE No. 12. I. White- or Cream- Burning Non-Calcareous Clays. A. Opt-n-buruiiig, more than 6'/< appaivnt porosity at cone 15. 1. Low strength. Clay No. Vc S.W. 11 8.4 12 10.6 37 16.7 38 5.6 62 7.3 63 5.5 + 64 5.7 91 5.5 103 5.0 128 8.9 129 7.7 134 6.8 159 13.3 100 11.5 19 19.9 194 14.1 195 14.4 208 9.2 209 12.9 235 6.6 236 13.3 237 6.4 259 15.7 268 6.0 % P.w. % W.P, 18.8 27.2 21.6 32.2 29.7 46.4 18.3 23.9 20.0 27.3 11.85 17.40 12.0 17.7 10.9 16.4 22.5 27.5 19.5 28.7 14.1 21.8 17.3 24.1 21.4 34.7 30.4 41.9 33.3 53.2 34.7 48.8 29.3 43.7 17.7 26.9 17.8 30.7 31.7 38.3 30.6 43.9 25.9 32.3 19.5 35.2 11.9 17.9 '.T.S. % D.V.S. 94 14.5 49 17.8 141 24.4 109 9.6 94 12.2 69 11.0 84 11.2 194 11.0 69 8.0 29 15.2 33 14.2 17- 12.1 135 21.5 84 16.5 171 25.9 95 18.7 188 20.5 +-50 16.1 4-90 22.5 Low 9.3 34 19.2 33 9.8 120 26.5 90 11.8 % D.L.S. 4.7 5.6 7.5 3.1 3.9 3.5 3.5 3.5 2.6 4.9 4.4 3.9 6.8 5.3 7.9 5.9 6.4 5.1 7.1 3.0 6.0 3.1 8.1 3.8 Soften- ing pt. in cone.s 28-29 26-27 34 33 34 33 33 30-31 35 32 33-34 32-33 32-33 32-33 31-32 32 33 32 32 30-31 29-30 27-28 34-35 33 2. Medium to high strength. Clay No. 15 28 29 44 45 57 59 90 93 109 137 S.W. 12.2 12.1 8.0 18.7 26.9 23.3 20.9 13.8 14.3 12.9 17.0 % S.W. % P.W. % W.P. D.T.S. % D.V.S. % D.L.S. % P.W. 13.3 14.0 11.8 13.6 15.5 13.3 24.0 16.0 16.9 13.4 20.6 % W\P. 25.5 26.1 19.8 32.3 42.4 36.6 44.9 29.8 31.2 26.3 37.6 D.T.S. 467 356 242 1375 1562 1744 221 370 350 437 211 % D.V.S. 23.4 22.7 15.8 34.8 49.4 44.4 32.6 24.4 25.2 25.0 28.1 D.L.S. 7.3 7.1 5.1 10.5 14.0 13.0 9.9 7.5 7.8 7.7 8.5 = Per cent shrinkage water. = Per cent pore water. = Per cent water of plasticity. = Dry transver.se strength, pounds per — Drv shrinkage, per cent dry volume. = Calculated Ihiear drying shrinkage, per cent dry length. Soften- ing pt. in cones 30-31 30 30-31 30 30 29 34-35 31 30-31 30-31 32 square inch, without sand. 268 DIVISION OP MINES AND MINING o a o O a 13 o O) d ■a Z ^C ^ S UJ to CO CO a cq < .a 1- £ .a o a B j> a 'a & o £ ti $ J2 ^ C o "-< o o O o o o o o o > fe?'^ 6?: > 6S^ o o CO CO l>- t^ t^ -<*< I ?0 W5 -^ 05 00 O ^H I CO* W3 OS 00 iC OO "^ OS O t^ CO W5 b* >0 *-H t^ O CI C^ »-« lO CO Tj< b- I OS ■^ i-« C^ ^H 00 O O OO CD OO CO « »C GO lO eC t^ ^ CO fC CO "-H 'OS Cq (N OJ CO »-< CO CO C^ t-H CO CO CO i-f CC ^ »0 "^ CO M d »-< f-H > M ^"•Oiot^r^ooco-^oco ^CO^^Tt^CflOlC^OOCOIMf-lt^lOl^OsC^fM-^Ot^C^CD »-ieo»OcO'-'cOiOcO.-iOS C0OcDkCTj<»-t»0Or-'^O*C0SCs^HT-(0>0SO'-i.-«,-( »-<.* CO *-(r-tCO CO _L I CO J_ C^ ^H »-( «-C<|iA CD OS M OS C71 CO M* OS h- CO O OOcDC^MO»OC^Oi0005MC^cD(M»f3 000iCWiOCO-^t-^C^ C<)C>CDOO»000«-<"*J1I>. > 65'^ ^: OPM COr^COiOCDOSCOcO»OTt ^^i-HCJi-HM OOOf-(W3cDOOOSC— tOsOSTjCOOt-^t-^»C»COC-lt-<000 C^OsiOcDOC^b-i-HO»OOs 0Si-(0s»-ic0i-ii0c0C^CSI»CiCiC0r^Q0OC0d00'-iO00'<^O CDOS'^Cq^O(N'-iCO»-lOOC^t^iC^HOS-^OCOI^OSC^(M C^ C^ I I C^ I _|_*-( » ,-.^1-1 c^l* OCO^HOOSI^C^(MOO^O QOI^OOTt*OSOSt^OO'^(>l C^COCOOOTficOOCOCOClt-iCOcOtOOcOOSt^l:^ ^i-iO:iOs»-Hi-Ht^OSCDOi»CCO«:)OSCOOSCO"^t^ CDOs'osi— ii-<0»-ii-H'^OOOi-«cOTt-'^t^Wt)'- &?: 52: Class No. CO"— 'CDCDCOI^-CO'^r-ii-HCS cOcDOOTj"iOC040kOC^CO I I " iOC^»-t^HCOOOtOi-Oi-HOC0OC0 ++^ I ^ I • ^ ■ ■ H JOSr-HOOQOC^'-'W300»--OCO»OCO^H-**t»-*OS T-HO'— 010 08 Ob 0^ OZ I 3 5 7 9 II 15 ir HEAT TREATneNT IN COIiES. '^cu ct ^ 10 u,/ t,-^ 2^ ^ § ?0 ».» § .' * A NO 12 9 m u ^•y .«_ .^^ _ .^ 1 a: 1 -J NO 13 4 * A 10 o 50 20 10 "^ S --• A No 15 9 \ ^ \ Nj «. S. _.. ^ ''■ •-V • ~ A IN a 16 D M N — - 20 10 n ... ^ _S. _ _ . — « _ . — — - -»" ""■" ... //EAT TREATMENT IN CONES. 270 DIVISIOX OP MINES AND MINING Ahsoriition and linear shrinkage curves for clays of class 1. CIO 08 06 Of OZ I 3 5 7 9 II 13 IS" ^ so % No 19 S A ^40 —■ <- ^ ^ so «40 1 ** ^ i ^ >< 1 — .^_ .•' ._. — NO Id 4 A, -J ~" 1 1 ^ .=u _ _ , _ _ _ . — . un 1 010 08 06 Of OZ I 3 5 7 9 II 13 /S" SO 40 No 195 A ■^ 30 20 10 O 40 s ^ . -- -- -• N 1 S .. ^^ ^ ^ No 29 A. — •«^ s KM^ w^ »•" A He 4^? - ^ **"" s HL 'f\l n iEA in EN T'i va y/i rj." 010 08 06 Of OZ / 3 5 7 S II 15 IS" ^ 30 'St 20 5 10 ^ 10 5 3C? I No 45" A ^ --> s __ No57| N A_ - S -. ^ rr ^>. > A Noisa r s K ^•» __ -- -- _S — — * \ X »£AT TREATMfNTlNCOfiES OiODBOb Of Oi I 3 5 7 9 II 15 /r i k. i -J I I 20 10 20 10 O 20^ fO O 20 10 O A No 30 _S ^. _^ __ __ _- ^ No 93 """ ■^ -- -^ _s ^ _ _- — No 10 9 — 1 A — — ■ s .. ^ ^ _A_ No 13 7 "-N — "X ._ JS ^ « -- -- -' ** — ' i"S HE/\T TREATMfNT IN C0fiE5. 272 DIVISION OP MINES AND MINING l-B. Dense-Burning, Less Than 6% Apparent Porosity Between Cones 10 and 15. 3. Generally Refractory, Softening Point Cone 27+. No. 70 (p. 169). Riverside County. Eniseo Clay Co. "White Plastic." This is a white burning, plastic fireclay, similar in its general properties to No. 56 (class 7), a German fire clay, but Avith lower dry strength, higher firing shrinkage, higher softening point, and whiter color. It contains 6.4:% of +200-mesh sand. It has a strong and smooth plasticity, medium low dry strength, and in the dry state it is soft and tine-grained. The colors are : dry, 13"f ; wet, 17'"'d ; cones 010 to 1, ll"f ; above cone 1, nearly white, but with a faint yellowish hue. Finger-nail hardness is developed below cone 010, and steel hard- ness at cone 02. Deep cracks developed in firing, but the pieces did not shatter sufficiently to fall apart. The total linear shrinkage, plastic basis, at cone 15 is 17.8%. The softening point is cone 32. The princi- pal use of the clay at present is in the manufacture of fire brick, but its white color, fineness of grain, and excellent plasticity should make it desirable for Faience tile and other uses. No. 96 {\).ni). Riverside County. Alberhill. G., McB. & Co. "No. 10." This is a white-burning clay with excellent smooth plasticity, that is extensively used in terra eotta bodies. It contains 1.2% of -+-200- mesh sand. The dry strength is medium, and the dried condition is medium hard, fine grained, and close textured. The colors are : drv, 17""d; wet, 17""b ; cones 010 and 08, 13"f; cones 06 to 13, buff white. Finger-nail hardness appears below cone 010, and steel hardness at cone 1. Absorptions under 10% are obtained at cone 9. The fired structure is sound and stony, and the texture is smooth. The total linear shrinkage, plastic basis, is 16.0% at cone 15. The softening point is cone 32. The best firing range is from cone 1 to above cone 13. No. 98 (p 171). Riverside Countv. Alberhill. G., McB. & Co. "Bone." See also No. 74, 86, 87, 231, and 232 in class 5 and No. 103 in class 1. In the natural state, the pisolitic structure of this clay is not so well developed as in some of the other bone clays from the district. It contains 30.0% of H-200-mesh sand. The plasticity is spongy and weak, the dry strength is low, and in the dried condition the clay is soft, friable and open-textured. The colors are: dry, 13"f ; wet, 17""b; fired, from cone 010 to cone 15, pinkish to yellowish white, finishing at a color that is whiter than that of No. 96. Finger-nail hardness appears below cone 010, and steel hardness is present at cone 3. All fired test pieces are hair cracked. The surface texture of the fired tests is smooth. The total linear shrinkage, plastic basis, at cone 15 is 18.3%. The softening point is cone 35. The calcined clay is especially valuable as a fire-brick grog. No. 120 (p. 53). Amador County. lone. Jones Butte. Arroyo Seco Grant. Leased by the Stockton Fire Brick Co. "Edwin Fire- clay." This is one of the best of tlie Tone fireclays. It contains 30.2% of -|-200-mesh quartz-mica sand. The plasticity is 'soapy' and moder- ately strong, the dry strength is low, and in the dried condition the clay is soft, medium-grained, and close-textured. Some fine-grained sand is present. The colors are : dry, 17"f ; wet, 17'"d ; cones 010 to 02, ll"f ; cones 1 to 5, pinkish white; cones 7 to 15, grayi.sh white. CLAY RESOtfRCES AND CERAMIC INDUSTRY ^73 8teel hardnoss is dovelopod at cone '-). Ijoss than 10% absorption appears at cone D. All test pieces develop a network of hair cracks on firinfr, bnt do not disintejzrate. The total linear shrinkajje, ]>lastic basis, at cone 1") is 2:3.0', i. The softeninpr point is cone 34. The calcined clay is nsed as grog, and the raw clay as a i)lastic agent, in the manu- facture of heavy-duty fire brick. No. 144 (p. 18o). Sacramento County. Michigan Bar. Van Vleck ])roi)erty. This is .similar to No. 143 (class 4), but contains more impurities. It contains but 0.6% of H-200-mesh sand. The i)lasticity is smofith and strong, the diy strength is medium low, and in the dried condition it is medium hard, fine-grained, and close textured. The colors are: dry. 17"f ; wet, 17"d ; cones 010 to 06. 13"f ; cones 04 to 1, ]7"f ; cones 3 to 15 whiter than 19"f. Steel hardness is developed at cone 1. Less than 10' « absorption appears at cone 7. The fired struc- ture is sound and stony, and the surface texture is smooth. The total linear shrinkage, plastic basis, at cone 15 is 20.6%. The best firing range is from cone 1 to cone 15. No. 273 (p. 163). Riverside County. Alberhill. A. C. & Co. "SH^." This clay is classed by California consumers as a ball clay, on account of its smooth and strong plasticity, its good bonding .strength, nearly white fired colors, and good vitrification range within commercial firing limits. It is very similar to the Florida kaolin (see No 59, class 2) . The proportion of + 200-mesh sand is 4.6% . The dry strength is medium, and in the dried condition it is medium hard, fine-grained, and close textured. With 50% of — 20-mesh to H-30-mesh Ottawa sand, the bonding strength is 70 lb. per sq. in. There is slight effer- vescence in hvdrochloric acid. The colors are: dry, 9"'f; wet, 17"'; cones 010 to 06, ll"f ; cones 04 to 5 whiter than ll"f ; cones 7 to 13, nearly white. Steel hardness is developed at cone 02, and less than 10% absorption at cone 0. The fired structure is stony and badly shattered at all cone numbers, and the surface texture is smooth. The total linear shriidcage. jdastic basis, at cone 15, is 22.4%. The soften- ing point is cone 34. It is used in stoneware and whiteware bodies. I-C. Dense-Burning, Less Than 6% Apparent Porosity Between Cones 5 and 10. 4. Generally Piefractory, Softening Point Cone 27+. No. 125 (p. 53). Amador County, lone (Carbondale). Arroyo Seco Grant. "Gage." This is a white, fine-grained clay, with a talcy feel, and smooth, but weak, plasticity. The dry strength is low, and in the dried condition it is soft and friable. The colors are dry and wet, white with a greenish hue; cones 010 to 9, pinkish white; cones 11 and 13, nearly white. The plasticity of the clay is not entirely destroyed until cone 06 is reached, at which point finger-nail hardness appears. Steel hardness develops at cone 5. Less than 10% absorption appears at cone 5, and vitrification is complete at cone 11. Slight bloating is notice- able at cone 13. From eone 06 to cone 9 the structure is stony, and above cone 9 it is glassy. No firing cracks develop. The maximum total linear shrinkage, plastic basis, is 19.8%, at cone 11. The softening point is cone 30. The best firing range is from cone 5 to cone 11. The clay has been used in the manufacture of calcimine, and is suggested as a possible ingredient of M'hite tile and stoneware bodies. 18 — 54979 274 DIVISION OF MINES AND MINING No. 143 (p. 185). Sacramento County. Michi;iran Bar. Property of Geo. Cutter. This is a line-frrained, cream-burnino:, plastic clay, quite similar to No. 144 (class ;]). It is not now in use, but was used many years ago as a stoneware clay. The plasticity is smooth and strong, the dry strength is medium, and in the dried condition it is medium hard, fine-grained and close-textured. The colors are : dry, pinkish white; wet, 21"'f ; cones 010 to 1, pinkish white; cones 3 to 7, 19''f; cones 9 to 13, 21"'f. Steel hardness is developed at cone 1. The fired structure is sound, and stony, and the surface texture is smooth. Less than 10% absorption is obtained at cone 5. The maxi- mum total linear shrinkage, plastic basis, at cone 11, is 23.2%. The softening point is cone 32. When used alone, the clay warps seriously both during drying and firing, but will stand much abuse without cracking. The best firing range is from cone 1 to cone 11. No. 240 (p. 52). Amador County, lone. Core drill sample. Ea.st side of Lot 237, Arroyo Seco Grant. This is a cream-burning clay. The dry strength is medium, and in the dried condition it is soft, friable, fine-grained, and close-textured. The colors are : dry, 15"f ; wet, l'"f ; cones 010 to 02, 13"f ; cones 1 to 7, 21'"f; cones 9 to 13, 23''"'f. Steel hardness is developed at cone 02, and less than 10% absorption at cone 1. The fired structure is stony, and one or two small cracks are present in each fired test piece. The surface texture is smooth. The maximum total linear shrinkage, plastic basis, at cone 13, is 23.6%. The softening point is cone 32-33. The long vitrifica- tion range is especially to be noted. The possible uses are as a refrac- tory bond clay in fire brick, terra cotta, faience tile, and stoneware. It is the equivalent of the well-known Dosch chiy, Xo. 136 (class 8), and has a slightlv better color. TABLE No. 14. I. White- or Cream-Burning Non-Calcareous Clays. B. Dense-burning, less than 6% apparent porosity between cones 10 and 15. 3. Generally refractory, softening point cone 274-- Soften- Clay ing pt. No. % s.w. % P.W. % W.P D.T.S. % D.V.S. % D.L.S. in cones 70 12.8 18.7 31.5 171 21.9 6.9 32 96 13.7 15.9 29.6 398 25.0 1 . 1 32 98 6.5 20.9 27.4 81 10.8 3.4 35 120 6.8 29.6 36.4 93 9.9 3.1 34 144 17.7 22.1 39.8 165 29.4 8.9 31 273 15.6 21.9 37.5 249* 25.7 7.9 34 * Bonding s trength, with 50% of Ottawa sand ( —20- ,-1- 30-mesh) is 70 lb. per sq. in. C. Dense-burning, less than 6% apparent porosity between cones 5 and 10. 4. Generally refractory, softening point cone 274-. Glay No. % S.W. % P.W. % W.P. D.T.S. % D.V.S. % D.L.S. Soften- ing pt. in cones 125 11.7 31.1 42.8 143 22.5 21.7 44.2 240 20.6 22.3 42.9 26 245 335 ity. pounds i)ei nt dry vol shrinkage, 16.5 36.8 33.7 • square inch, unie. per cent dry 5.3 11.0 10.2 without length. 30 32 32-33 % S.W. =: Per cent shrinkage water % P.W. = Per cent pore water. % W.P. = Per cent water of plastici D.T.S. = Dry transverse strength, % D.V.S. =: Drying shrinkage, per ce % D.L.S. = Calculated linear drying sand. CLAY RESOURCES AND CERATSIIC INDUSTRY 275 o S ^ S c + § + s. J= 1 , -^ -*-- >^ c >. ,~ to 5 o 1 c n be E. bc Z ■^ -^ CJ UJ 'E 53 V. L) L. X cd < 3 CO 1- a OS o •- ^ ^ %^ o ■J3 >. ♦^ ^■ o 00-7: 5 -■ 1 ■* '-; ci — »c o c; -^ ■ aa-s ^^i O C »C O -^ CI CM 5C C-. C IC — CO C^4 CO lO CO Tf CO CJ o < OS <© eo b* t* »« t^ O U5»^t^00 < 00 to CO ^ CC Oi coeor-OM cs CM CM CO iO CO CO coco -^ c '■'i o ffl r>- Ci t^ ^ "-I CM ?0 C: O: OO CM — — OOiN < O 5C — -*OD^ •-r " -i c: oo cn CJ C^» CO -^ C^ CO c; CI 00 cr. 00 — . — CM CO CM CM COOOS fM COOO CO CO CO CO a; o '^i »-" « o 00 o :o O CO O CO »0 r^ CO CM ■<*• CO CM C^ t^CM to CO CI CO U5 t^ o: CO 'T coco CM ^ O O — — — CO CM CM OCM 3S Tf cooo — CM CO o t^ Tfi-- c: oo O -rj. oo o ^^ c:; CM CO CM ■* Tt< CM CO h- O CM 000-0 *0 CM O O iCO «:: 00 C5 +5.3 11.0 23.5 s 5 '^f CM r- CO t^ »o CR ^CM !r>r- o CO CO -^ f CO -^ CM CM CO CO 00 Oi ■^coco iC -r -J3 O O -f -f -f o :r »c CM t* »o b- o oo -^ o 3 c O ?0 CMCO SO'* oo — CI a= 00 — coco "^ TfCO-* COO-^ r^r^ OS -rf CO CO ..^ >o o; CD -<*• »c o ■»»• CO OS »0 'f o '* Cs iC O t^ o - c ^^^ to ^- O CO -* W3 oo ^ CI u^ r* ^ CO CO ■* -^ CO Tf coc; o «Dt-0 TfCO -^ rf ^ ■^ r-co ^ -^ O CO CO c; '^ -^ o cO^-« 1 o o 5 ^:: 00 1-^ "* 00 '^ o t^ ^ ^ CS t^ CM CO CO -^ CO CO '«. p" »^ 20 u,,- V) J 10 ^ tt- a- u s- ^--- — — , — .S -- — — '' ~- J HEfiiT TREATtieNT IN CONES. ^ JO ^ 10 »■■ § zo I 20 I ^ 10 *« A No 120 ^ \ \ > V — ■ - s. . a.. -' \ ^ — _ No 14 4 A ^ s \ ^ ^, ,- _s _. _- -' ^ — N Nc273 ^ A N V. ^ ^ c "■ ^^ -- — — .4 -' — \ >^ ^£AT rREATMfNT IN CONES. 010 OS Ob 0^ OZ I 3 5 7 9 II 13 IS" /f£AT TREATriENT IN CONES. CLAY KESOUKCKS AND CEKAMIC INDUSTRY 277 II. BUFF-BURNING CLAYS. A. Refractory Clays, Softening Point Cone 27 4 a Oi'EN-BrHNixc. Mori: Than 6'/< Aitahknt Pohositv at Cone 15. 5. Low Strength. Xo. 17 (p. 168). Riverside County. Alberliill C. & C. Co. "Bone." A medinm-grained bone clay, witli a deeid(>d, bnt not well-developed pisolitic .structure in tlie eruile state. It is used in the manufacture of fire brick, high-temperature cement, and to some extent in saggers. It contains 29.0 ';f of + 200-mesh grains, has short plasticity, and dries rapidlv to a soft, rough textured condition, witli medium low dry strength. The colors are: dry, l;}""d; wet, l;i""i; cones 010 to 06, 17''f ; cone 04, 17'''f ; cones 02 to 5, whiter than 17'"f ; cones 7 to 13, 17'"f. All test pieces fired above cone 02 were 'crow-footed.' Finger- nail hardness is developed below cone 010, and knife hardness appears at cone 5. The total linear shrinkage, plastic basis, is 18.5% at cone 15. The softening point is cone 34. The best firing range is above cone 5. The principal value of this clay is to increase the refractoriness of fire brick bodies. No. 23 (p. 163). Riverside County. Alberliill C. & C. Co. "West Blue." This is one of the more important Alberhill clays, and is widely used for light-pink and butf face brick, for sewer pipe, and in fire brick to decrease porosity. It contains 11.0% of + 200-mesh sand. The plasticity is excellent and the dry strength is medium low. In the dry condition the clav has a medium hardness, a fine grain and a close texture. The colors are: dry, 17""f ; wet, 21"" ; cones 010 to 04, 5'f ; cone 02, ll"f ; cones 1 and 3, 13"f ; cones 5 to 9, ]7"f ; cone 11, 17"d ; cones 13 and 15, 15"b, with prominent iron specking. Finger-nail hardness is developed at cone 08, and steel hardness at cone 3. The maximum total linear firing shrinkage, plastic basis, at cone 13, is 13.7%. Slight bloating is apparent at cone 15. The softening point is cone 29. The best firing range is from cone 1 to cone 13. A pleasing mottled texture can be produced by flashing. No. 66 {\).\ld). Riverside County. Corona. McKnight pit. Pacific Clay Products Co. "Red IMcKnight." This is a bull'-burning clay containing a large proportion of non-plastic material. It is suitable for face brick manufacture, and as an ingredient of sewer pipe mixes. The plasticity is good, though weakened by the presence of 54.4% of + 200-me.sh sand. The dry strength is medium low, and the dry con- dition is coarse, open, soft and friable. The colors are : dry, 9" ; wet, 9"i; cones 010 to 02, 9'b; cone 1, 9'd ; cone 2, ll'd; cone 5, 9'f ; cones 7 and 9, 9"d; cones 11 and 13, 15"d. Fing<>r-nail hardness develops beloAV cone 010, and steel liardness at cone 7. The fired condition is sound, open, granular, and medium strong. The total linear shrinkage, plastic basis, at cone 13, is 5.6%. The softening point is cone 28. The best firing range is above cone 5. No. 67 (p. 179). Kivt'i-silastic matter than No. 190 or 191, but at the same time contains sufficient iron to iiivc pale ImlV lii'fd colors. The residue on 200-mesh is 26.2^;. The i)lasticity is fail', the dry stren«>th is medium low. and in the dried condition it is inediuiii-hard, fine-jirained, and open-tex- tured. The eoloi-s are: dry. pinkish white, wet, 17"f ; cone 010, 13"f : fadin 87 104 126 138 140 141 142 191 192 231 232 239 244 2.50 270 282 285 TABLE No. 16. II. Buff-Burning Clays. A. Refractory clays, softening point cone 27 4-. a. Open-burning, more than 6p,. cent shrinkage water. — Per cent pore water. = Per cent water of plasticity. = Dry transverse strengtli, i)r>uiuls i)er sfiiiare r= Drying shrinkage, per cent dry volume. = Calculated linear drying shrinkage, per cent dry length. inrli, without sand. 284 DIVISION OF MINES AND MINING ^ o o c Z c III 3 -1 on OQ if < 3 e o O :0 CM CO 1 t^ --CM -CM ' ifi . -r — t^ ^o — Cr;0~i- CM ■ — — — Tf . 'OO "^ o ^ ' ' 00 CI 00 CM ' 'CM CM ' cr, cooo or I- CI *-* 0»fr -OS 'i^ 1^ ^ < O 1 C^l co^ .^ lie -^ 1 CD -tj« -^ ^ iC 'CO »c t^- o ICO -*■ CO CO CS > ■ IC OC CM O > 'OCOCO CO • >CO -f -rf OCM CD ' CD CI CI ' CM CO CM CO o O OOCMOOt— CMCM:0-*'--rO'. ^XiCr. ^COcCOCMcDOWS'tJ'Or-' CO »— CM CS i-* CM — CM CM CM ^ CO CO CM CM '^ CO CM ^ CO w-" CM CM tJ" oocM't-r*^cooourc^OTpr-c^)t^-*'t^'X;c»ocococciiooc^i CMCOCOOOCO'rt.OOCM-^C^I«l.yDy3»f500--|-^-^QOO^CO>0 0-fO C-tiCM CM-TfCM CMCOt^CO— OICO CMCOf OIOICMCMCM o o O cc — »c •* >c in Qo o t^ CO CO cr- CO^ •— COC-J O'lCOM'CO^ C^ICO C^ICOCO 05 O O 3;OlOCMOOiCClX;.--MI^Cr. 1— CMOU3C:C0CMOCMt^00'^CMOC ;o-t<-^«3^ — 'fiTGO-^r^cot^ooi^ior^t-oococooot^cniCCM CMCMCMCMCMCO'-'CMCMC'l CMCOCOCMCM-fCOCO^CO ^(MCM-^J- C^OOf— OOC-rCO — ^GOCOCl — •'^o^cuo-ri-^'—oicococ^jcoicic cj; oo CM t- 00 :c »o CO CM 'Tj* 1 ■*— 00 C3 »c CO CO cr. »o t^ o :o CO -r CO t^ t-^ ic i^ t^ CM »o CMCOCMCMCMCO — CMCOCl CMC0C0C^1CM-*C0'^01 > — CNiCCOC:C CO CI -^ CD CO r- 00 I-- — CO 0-- 1^ "^ uo -f a. cr. »o — 00 — LO GO COCOCMC^lCM^ClCMCOCOCO-^CO^COCO'^'t'^Ol OCM'<**t^CMOOCOI^CD--*'«*t^OO'^CMOOO — CMCD 'Osor* ' o OS r^ t-O — -S-CMinOlOCOOCM — 0^0-rfCO»0 — CO — -- — CM— |— CMC^)^— =», CMC-1 — CMC^l c of^ ""-H oiiouoco- oo>o-rOi — O3ico— •r^cM»C'cr^ocMOoo-n*oo 00 -T Ci CO GO ^ CO O :r-. O QO CO O r: CO O Cr. C^l -JD T," ic cc o ic 3; — COCOClCMCM-n'CMCOCOrOCO'^-^'C^-^'r-^-r'^J'COCOCMCOCOCM''^ ++ , ^'^ ^ — CO»C»COOCMCOCMCO>— «Ot^OcD»— 'I~*COai»— — ^t-t^'— tCOiO COCOOCOOCOCO — — OClCOt^ — OCMCMCIOO — — c:cooi*or^ o a. o O ococor-CMO-ri-cococoy^oocoOookOcoo 'CO OCOOOOOOt^ — 310 0-. 0»C — OCOCMC:-Tf iOO ':J^COCMCv|CO-^COCM-:t"CO'rrTr-rf-^-^T*>-rt'Tt< .CO • »CCM O • 00 C 1 CI ■ coco -^ < ^C'l — cDc0CMi0»CU0Ot-^— C^l'^OCOCO'1' -OS 1 O CM CD ' iC CI >c CM CD OCO t^ QOO — CI — CO O irt O O; O CM O ' !£) o o c lOiC — I^CMCO^X>C-lO0=r. COCD-tf-TfiOiOl^O^^ CM^CJ:cr>-:fCr. COCTO — — CO — o^cocrcocD — rJ"COC^lC'lCO'^CO CI "Tf "rt< ' CO CO tT CD — OOOCOOOO — COiOCOOwOOC-lCIClCCl ioot^ -* ' — oo»o r-oo — ocico(Nr^oooO'**'Tj«or>-c»^»oooo + 1-1 1^ CO CO t^ — 'ff 1^ — CM CO CD r^ r^ r^ 3;cor-^;ococ;— oj — CM — c^ic^. l-^ 00 OO O C^l CO ■^ -^ «T O". C"- CO CT CO -*• :r: o CI »C — ic r - 00 CO CM Ol CM CI CI Class No lo + o o o + o o — — iZ in Ct, 6? > PLAY RESOURCES AND CERAMIC INDUSTRY 285 AlisiirpLii'ii ;i"il liiuar sluinkaKi' cuims I'lH- rlavs n( class 5. •-0 5 Or. Or: i -J 010 08 06 Cf 02 J 3 5 7 S II 15 /T 20 10 O SO 10 10 10 o ° /iEfi T TRlfMNEN T IN COnES. A — \ Noi 17 1 <. — . V \ — fC< X .. ._ _s -- N < Nc .23 ^ \ *> ,^ — —j s .. — • .-• -- ^v -J A h-H Hs _-- - X ^ ___ I^l0| [79 10 ^■~ ■ — ■ *^ S A No 86 ZO ■"■ N — — IQ n .j^ -- _s — — — ^<** //EAT TRErn'MENJ INCOMES. 010 08 0b Of OZ I 3 5 7 9 II 15 /S' 010 08 06 Of OZ I 3 5 7 9 II 15 /T //EAT TREAinENT IN CONES. HEAT TREATnENT IN CONES. 286 DIVISION OP MINES AND MINING Absorption and linear shrinkage curves for clays of class 5. 010 OB 0(> (H OZ I 3 5 7 9 // /J /T 5 /o I •~J frS •» ^" 30 S' > A ■^ No 232 ! '*v. 1 N — , »-< -' — . -- .- -- .S_ -- -- -' 'V -^ ^ No 23 9 S No,24W ^ .-+-1 's ^ >■ NaZSO k s 's' ^ •"'^ r HEfiJ TREfiTilENT IN CONES 01008 0b OfOZI J S 7 ^ II lis IS- I ft: -J 5? I I 50 20 /O zo 10 ^ 30 20 10 No .27 — A ■"^ ^ s^ .?. *** -•- -- ,.. — .— -^ A No 28 2 ""* ■^ N» ». ... ... S -- -- ... ... ... ... I^s \ No 28 5 "^ ^ A^ — . ^ ^ .^ — ^ J. — __ __ //-^/)7 TRE.'MnENT IN CONES. CLAY RESOURCES AND CERAMIC INDUSTRY 287 (i. .Medium to lli.uli Strength. \o.!J {\).\ii:i). Riverside County. Alherlnll. (". (fc ('. ("o. " Hill liluo." See No. 271, and 274 in class 7, and 272 in tliis class, Avhicli are better samples of the material that will be available in the future. This is a smootli, fine p-rained, bulf'-burniii of +200-mesh sand. It is used in art tile, stoneware, terra cotta, and sagger bodies, and represents one of the most widely used of the Alberhill clays. The colors are pinkish and buffisii white, approximating Kidgway's "f" tone. Finger-nail hardness is developed below cone 010, and steel hardness at cone 02. Vitrification is well advanced at cone 13. The maximum total linear shrinkage, plastic basis, is 13.3% at cone 13. lUoating is apparent at cone 15. The softening point is cone 29. The best firing range is from cone 04 to cone 13, and hard, strong bodies with absorptions below 10% are obtained above cone 3. No.Uiii.lG'^). Riverside County. Alberhill C. & C. Co. "A-Clay." This is a pink and buff-burning plastic clay used in the manufacture of face brick. It contains 19.27o of -|-200-mesh sand, develops excellent plasticity, has a good dry structure, and nu'dium high dry strength. The colors are: dry, 17'"d; wet 17"'b; cone 010, 9'f ; cones 08 to 04, 5'f ; cone 02, ll"f; cones 1 to 5, 13"f ; cones 7 to 9, 17"f ; cone 11, 17"f ; cone 13, 15"d. Finger-nail hardness is developed below cone 010, and steel hardness at cone 3. The total linear shrinkage, plastic basis, is 11.1% at cone 13. The softening point is cone 31. The best firing range is from cone 3 to cone 13 or above. A wide range of butf and pink colors can be secured in the normal kiln run. No. 27 (p. 163). Riverside County. Alberhill C. & C. Co. "No. 10." This is a pale buff-burning clay with excellent smooth plasticity, medium-high dry strength, and a medium-hard, fine-grained, close- textured dry condition. It contains 2.6% of -j- 200-mesh sand. It is used in sagger, art tile and dry-pressed brick mixtures, and was for- merly used in architectural terra cotta. The colors are: dry, 13'"f ; wet, 13'"k; cones 010 to 1, 15"f ; cone 3, 17"'f ; beyond cone 3, to cone 15, increasing yellow, decreasing i)ink, with scattered fine brownish and black specks. Finger-nail hardness appears below cone 010, and steel hardness at cone 3. The total linear shrinkage, plastic basis, at cone 13 is 16.1%. Bloating is apparent at cone 15. The softening point is cone 30-31. The best firing range is from cone 3 to cone 13. The smooth texture, light colors, and excellent plastic, drying and firing qualities of this clay make it especially desirable for many purposes. No. 33 (p. 205). San Diego County. Cardiff. Vitrified Products Co. See also No. 34. This is a light-colored fireclay, of Pleistocene ( ">.) age, containing 41.0% of -f- 200-mesh sand. It is used for fire-brick and for buff or cream face brick. It has weak plasticity without stickiness, medium-high dry strength, and in the dry state it is hard, with a granular structure. The colors are : dry and wet, yellowish white ; cones 010 and 08, 13'"f ; cone 06, 17'''d; cones 04 and 02, 15"d; cones 1 to 13, 17"d. These colors, coupled with a granular texture, make pleasing effects for buff and cream face brick. Finger-nail hardness appears below cone 010 and the hardness at cone 13 is slightly less than steel. The total linear shrinkage, plastic basis, at cone 13, is 8.6%. 288 DIVISION OF MINES AND MINING The softeninj? point is cone 30. The best firing range is IVom cone 1 to fibove cone lo. N(/. .'>'/ (]). 'JO;")). S;in Dic^o Coiinly. CnrdiiT. N'ili'ificd I'l-odncts Co. See also No. 'A'-i. This chiy is from another part of tlie same bed from which No. 33 was taken, and is similar to it in every respect, but has less sand, more iron, strongei- plasticity, and slightly greater shrinkage. It contains 31.0% of -|-200-mesh sand. The colors are: dry, y"'f ; wet, 9'"d; cones 010 to 04, 7"f ; cone 02, l"d; cones 1 to 7, ]5"d; cones 9 and 11, 17"d ; cone 13, 17"b. Steel hardness appears at cone 13. The total linear shrinkage, plastic basis, at cone 15, is 11.5%. The softening point is cone 31. The best firing range is from cone 1 to cone 15. No. 53 (j). 195). San Bernardino County. Hicks. Millet and Kennedy. This is a buff-burning, plastic fireclay o" Tertiary age from an undevelojied deposit. The plasticity is good, the dry strength is medium high, and the dry condition is hard and close grained, with a heterogeneous texture caused by the presence of non-plastic grains of a different color than the clay portion. The sample contains 10.4% of -)- 200-mesh material. The colors are : dry, nearly white ; wet, 19"f ; cones 010 to 1, ll"f ; cones 3 to 9, 17'"d; cones 11 and 13, 17'"f, mottled, with slag spots. Finger-nail hardness is obtained below cone 010, and steel hardness develops at cone 02. The fired structure is sound throughout, and vitrification is well advanced, but not complete, at cone 15. The maximum total linear shrinkage, plastic basis, at cone ]3, is 20.1 *;(. The softening point is cone 30. The best firing range is from cone 04 to cone 13. The clay is suitable for the manufacture of pink and buff face brick, and as a bond clay in fire brick. It is possible that material of improved qualitj' can be found if the deposit is developed. No.76 {\).\1^). Riverside County. Alberhill. L. A. B. Co. "Gray No. 23." See No. 77, class 5. This is a plastic buff-burning fireclay that is particularly useful in sagger and pottery mixes. The clay con- tains 2.2% of + 200-mesh sand, the ])lasticity is excellent, the dry strength is medium, and tJie dried condition is medium hard, fine- grained, and close-textured. The colors are: dry, 17'"f; Avet, 17'"d; cones 010 and 08, 7'f; cones 06 and 04, 9'f ; cone 02, 13"f ; cones 1 to 13, 17''"f, or slightly whiter. The fired colors are good buffs and creams for face brick, faience tile, and similar ])roducts. Finger-nail hard- ness is developed below cone 010, and steel hardness at cone 1. The fired structure is sound and stony, and smooth textures are obtained. Absorptions below 10% are obtained at cone 9. The maximum total linear shrinkage, plastic basis, is 15. 6*;;, at cone 11. The softening point is cone 29. The best firing range is from cone 1 to cone 13. No. 78 (p. 174). Riverside County. Alberhill. L. A. B. Co. 'No. 10." This is a dark colored, butt'-burning, plastic fireclay, con- taining carbonaceous matter. It is used for fire brick and face brick. The sample contains 16.2% of + 200-mesh sand. The plasticity is excellent, the dry strength is medium-high, and the dried condition is medium-hard, medium fine-grained and close-textured. The colors are : dry, 13'"'d; wet, 13""i ; cones 010 to 04, 9'f; cone 02, 13''f; cones 1 to 13, between 17"'f and 21"'f, although slightly whiter at some cone <li temperatures. P'infrer-nail haiduess appears below cone 010, and steel hardness at cone 1. Absoi-ptions above lO'y are found above cone 8. The fired strneture is sound and above cone 02 is stony. The total linear firing slii-iidcage, phistic basis, at cone 13, is IT.l^r. Slight bloating- w^as noted at cone L'v The softening i)oint is cone 29. The best firing range is from eone 1 to cone 13. The plasticity, dry and fired strength, and wide vitrification range at commercially attainable temperatures are the most valuable properties of this clay. Xa. 81 (]). 174). Riverside County. Alberhill. L. A. li. Co. "No. 25." This is a i)lastic fireclay, similar to No. 76, but with more coloring matter, and a higher jn-oportion of clay substance. It is used for face brick and fire brick. It contains oidy 1.8'/^ of +200-mesh sand, the plasticity is smooth and strong, the dry strength is medium high, and the drv condition is medium soft, fine-grained, and close-textured. The colors ^are: dry, 17'"f; Avet, 17'"b ; cones 010 to 1, ll'd; cones 3 and 5, ll'f ; cones 7 to 11, 17'"f ; cone 13, 17"f. These are suitable butfs and tans for face-brick manufacture. Finger-nail hardness appears below cone 010, and steel hardness at cone 1. Absorptions below 10% are obtained at cone 7 and above. The total linear shrink- age, ])lastic basis, at cone 13, is 15.8% . The softening j^oint is cone 28. The best firing range is above cone 1. No. 84 (p. 174). Riverside County. Alberhill. L. A. B. Co. "Main Pit Fireclay." This is a i)lastic fireclav, similar to the "Main Tunnel" clavs mined bv the Alberhill C. & Co. Co. and by G., McB. & Co., see samples No. 15, 29, 90, and 93 in class 2, and No. 13 and 229 in class 7. It contains 11.0% of +200-mesli sand, the ])lasticity is smooth and strong, the dry strength is medium, and the dry condition is soft, fine-grained, and close-textured. The colors are: dry, 17"'f; Avet, ]7"'d; cones 010 to 13, 9'f to 17'f. Green staining is pronounced. Finger-nail hardness develops below cone 010, and steel hardness at cone 3. Less than 10% absor])tion is obtained at cone 5. Vitrification is well advanced at cone 13. With the exception of a few cracks that resulted from the rapid fii'ing schedule used, the fired test jiieces are sound. The total linear shrinkage, plastic basis, at cone 13 is 12.2%. The softening point is cone 28. The best firing range is above eone 3. The clay may be used in fii'c hiick, face brick, faience tile, stoneware, and pottery mixes. The color is not white enough for whiteware bodiea No. 92 (p. 171). Riverside County. Alberhill. G., McB. & Co. "Yellow Main Tunnel Clay." This is a i)lastic, butf-burning clay that can be used in fire brick ami face brick. It contains 16.8% of +200-mesh sand. The ])lasticity is smooth and strong, the dry strength is medium-high, and in the dried state it is medium hard, fine-grained, and close-textured. The colors are: dry, 17"d; wet, 17"; cones 010 to 02, 7'd; cones 1 to 7, 7'f; cones 9 to V.\, 17"d. Scattered slag spots appear above cone 9. Finger-nail hardness appears below cone 010, and steel hardness at cone 1. Absorptions under 10% are found at cone 11. The fired structure is sound, and at high tem- ])eratures, is stony. The total linear shrinkage, plastic basis, at cone 13, is 13.6%c. The softening point is cone 28. 19 — 54970 290 DIVISION OF MINES AND MINING No. 97 (p. 171). Riverside Connty. Alberhill. G., Me.B. & Co. "Smooth Bunker." Thi.s is a hufir-bnrniiif!: terra eotta clay with excel- lent plasticity and medium higrli dry strengrth. Tlu^re is slight ett'er- vescence in hydrochloric acid. In tlie dried condition it is soft, fine- grained, and close-textured. Tt conlains 15.6% of +200-mesli sand. The colors are: drv, 13""d; wet, 17""d; fired, from cone 010 to cone 13, 13"f to 17'"f. ^ The color at cone 13 is deeper than in No. 96 (class 3), and a few iron specks appear which are not present in No. 96. Finger-nail hardness appears below cone 010, and steel hardness at cone 02. The fired structure is sound and stony, and the texture is .^lightly rough. Absorptions under lO.O'/r are obtained at cone 11. The total linear shrinkage, pla.stic basis, at cone 13, is 11.4%. The soften- ing point is cone 31. The best firing range is from cone 1 to cone 13. No. 102 (p. 171). Riverside County. Alberhill. G., McB. & Co. "Sloan Sand." This is a sandy fireclay witli fair plasticity, medium dry strength, and a medium-hard, medium-grained, open-textured dried condition. It contains 30.6% of -}-200-mesli sand. The colors are : dry, 17"f ; wet, 15"; cones 010 to 02, 9"b; cone 1, 9"d; cones 3 to 11, 13"d; cone 13, 17"d. At cones 11 and 13, scattering gray and brown specks appear. Finger-nail hardness appears below cone 010, and steel hardness develops at cone 3. The fired condition is sound, granular, and rough-textured. The total linear shrinkage, plastic basis, at cone 13, is 9.7%. The softening point is cone 29. The clay is suitable for the manufacture of face brick, and as an ingredient in low-grade fire- brick mixes. No. 108 {p. \1^). Riverside County. Alberhill. Pacific Clay Products Co. "Tapper Douglas." Tliis is a deep buflf-burning sewer-pipe clay with good plasticity, high dry -strength, and in the dried condition it has finger-nail hardness, and a fine grained and close texture. It con- tains 5.8% of -)-200-mesh sand. The colors are: drv, 17"f; wet, 13"d; cones 010 to 02, ll'd; cone 1, 15'd; cones 3 to 13^, 15"d. Steel hardness is developed at cone 1. Less than \Q% absorption is developed at cone 3. Vitrification is complete at cone 11, after which bloating begins. The fired structure is sound and stony. The maximum total linear shrinkage, plastic l)a.sis, is 20.0%, at cone 11. The softening point is cone 27-28. No. 130 (p. 62). Amador County. Toiu\ "Newman Carbonaceous Sand." This is a fire sand high in carbonaceous matter for which no uses have been found. Some iron compounds are present which are partly soluble in the mixing water, and cause discoloration by efflor- escence. The residue on 200-mesh is 16.0%. More clay is present than in No. 129 (class 1), resulting in better plasticity, and medium dry strength. The interior colors are: drv, 15'""b; wet, 15""m; cones 010 to 1, 15"b; cones 3 to 5, 13"b; cones 7 and 9, 13"b. The efflor- escence has a 5'i color from cone 010 to cone 1. Steel hardness is approximated at cone 3. Tlie fired structure is sound, fine-grained, and open textured. Light hair-cracks appear on the surface of test pieces fired above cone 3. The total linear shrinkage, plastic basis, at cone 9, is 11.6%. The softening point is cone 27. No. 139 (p. 52). Amador County. lone. M. J. Bacon. "Bacon Blue." This is a fine-grained, cream-burning, plastic clay that is CLAY RESOURCES AXD (■EKA>tIi' IXDUSTRY 291 suitable for stoneware maiinfactiire. It contains 1.4% of -f-200-mesh sand. The plasticity is very grood, the dry strenprth is niedinni Ioav, and \u the drii^l coiidilion il is niediiiin-hard. fiiic-^nviined, and open- textured. The c<)h)rs are: dry, l:5""f; wet, 17""f; cone 010, 17"f, changiuf? to pinkish white at cone 02, then to cream-white up to cone 9; cones 11 and 13, 19"d. Fiufrer-iuiil hardness is approximated at cone 010, and steel liardness develops at cone 7. Less than 10% ab.sorption is developed at cone 9. The fired structure is sound and stony, and the surface texture is smooth. The total linear shrinkales of "Hill Blue" clay. The percenta^'e of -f-200-mesh sand is 87.0. The plasticity is good, the dry strength is medium, and in the dried condition it is medium-hard, coarse-grained, and open-textured. There is slight effervescence in livdroelilorie acid. The eoh)rs are: dry, 18""f ; wet, 15"'"f ; cones 010 to 1, 13''f ; cones 3 to 9, 17"f ; cones 11 and 13, 17"d. Steel hardness and less than 10% absorption are developed at cone 11. A mottled and heterogeneous fired .structure is produced by tlie ]U'esence of a large percentage of ferro-magnesian minerals. The fired structure is sound, and the surface texture is rough. The total linear shrinkage, plastic basis, at cone 13, is 9.8%. The softening point is cone 29. Clay No. 9 14 27 33 34 53 76 78 81 84 92 97 102 108 130 139 145 150 197 257 258 263 266 272 TABLE No. 18. II. Buff-Burning Clays. A. Refractory clays, softening point cone 27 -f. a. Open-burning, more than 6% apparent porosity at cone 15. 6. Medium to higli strength. % S.W, 12.6 11.6 15.5 10.6 9.0 25.2 13.5 17.4 16.7 11.4 15.0 11.8 9.9 27.1 14.2 16.5 17.4 20.7 33.7 2i.8 9.7 21.5 8.9 10.2 % P.W. 13.3 12.4 14.8 11.4 13.6 19.1 18.1 19.4 16.8 12.7 13.5 14.1 14.0 13.1 22.9 17.8 21.0 18.5 31.9 19.5 16.1 20.0 15.2 12.5 Soften- ing pt. 'c W.P. D.T.S. % D.V.S. % D.L.S. in cones 25.9 770 24.8 7.7 29 24.1 420 22.6 6.9 31 30.3 458 28.6 8.6 30-31 22.0 550 20.7 6.4 30 22.6 449 17.5 5.5 31 44.3 795 42.4 12.3 30 31.6 240 23.9 7.4 29 36.8 462 29.1 8.8 29 33.5 414 30.0 9.1 28 24.1 326 22..-. 7.0 28 28.5 480 28.8 S.7 28 25.9 412 22.3 7.0 31 23.9 271 19.0 6.0 29 40.2 -t-1118 52.3 15.0 27-28 37.1 3S7 22.5 7.1 27 34.3 201 28.7 8.7 29-30 38.4 447 29.1 7.8 30-31 39.2 337 35.7 10.7 32 65.6 529 44.9 13.2 28 41.3 403 36.7 11.0 32 25.8 217 18.1 .-).7 28-29 41.5 417 36.2 10.8 32-33 24.1 231 16.4 5.2 32 22.7 348 19.8 6.2 29 % S.W. = Per cent shrinkage water. % P.W. = Per cent pore water. %W.P. = Per cent water of plasticity. i).T.S. = Dry transverse strength, pounds per square inch, without sand. % D.V.S. = Drying shrinkage, per cent dry volume. % D.L.S. = Calculated linear drying shrinkage, per cent dry length. 594 DIVISION OF MINES AND MINING + « M ~ ^ Sf M o S £ 22 O - 5 Ol b£ C- r! o c .— n hfi Z UJ -J en c 3 00 a5 O e < 1- 3 03 ^ (IJ 1-) — >, o s to a c a: 3 < c: u o O O o o o 6§: -0-^ ^"S ^'S 2 OS V .^- 6? ,.» 03' 6 Class No., c^)!:r:ooico — t^r^r^oo-^r^^-'- iO'^iCOiftooc^t— 400cooOTfi— . oo»oc^^'^lco — »o^-'-'»crocMQCTf »-<-HoorO'-''«t*»co»o^aiOiooo 00 --o ^ oo -^ ci I* Ci -^ ^M h^ ,-4 ■^o-^cjcccc»or-co^--^u^ocooioict— 00OC0C0»0— CO^iOCOOOiO "^ C*3 OO W C-l OSO i-^cD CO ^ ■^lOOOC^C^U^-^CCOt^OOOCC-^CiThMCOM t^COiOC— iSi— 'CO»CO> •CO(M-.CiCC--^*'OeDC0(M 00 r- ?o »c c^ (X) c CQ-rt-^jTCOO^OOiC^-OOC^rfCO — r-tMOOlOlO r^C0t-OcDC<»0'JC^tDTr»0C^»-'0iC0'irTt<»0»-> + - ~ + OiCOi— ";CC:C^:D-^-^C0— 'OOiC'^O OTj*l>.cOt^t^-.OC^J:CiOO'— 'OO'-'OOCOOOCO + + I 00 O O — « O O lO : ;c-)C>T»ooc»CfMcor^co»c dOt-Xi-^OOI^OO'-HCOcO^'-'OS-^QOO-^-^ c^c^coO(MTi«c^coTfO^"0-*io — o«; — + + I OOt^^O^S— •■^«C'^C^OO^C»C-^' ioi>-a5cot^t--coiot^eoiO'*oi'^cooiO'— ' + I +1 t~-O'^'-*C^:DCCiC0i'}«C^r-0:C0»C*C00'^ tcooroo r:»or^coooa;'-«'Oi^'*':sr-io [ III ■«* 00 eoeq + OO i^O ■ T-« to i o o 03'*r-corfco:ooO'-'T^(Mr*«ooooiW30i-»t>-ooco«oc^ — c^jeoco»ot^t^oooooiOsoOfocc-rr'tcciioi.o:coi-^ + o o * + o 0,, II CO > CLAY RESOURCES AND CERAMIC INDUSTRY 295 Absorption and linear shrinltage curves for clays of class 6. 010 08 Oh Of OZ. I 3 5 7 9 II 15 /£■ I a: i I I 20 JO 10 10 20 10 20 10 5 ** oU^ 1 — 1 No 9 1 — A ">v J S ^- • ■ " — >•- -.. ' — l—i < A No 14 ^ T. L!, • -• — .— A No 27 "^ ^ .5. ,» • ... ... ... ■^^ rr- <. >< No 35 A ^ " — ■ S^ ^m* .-4 .. -- . * H -- ^ __ 010 08 0b Of OZ I 3 5 7 9 II 13 /T ^, /O 5 o 5: t" I c: 20 I A 1 Noj34 r- "^ ■^ -= ... > J. .-' ... ... • • • ... .^ , ^ S» No|s5 I ■■■' V "V ,S. ^» ,-• j ■"" ... ... "^r A NoJ76 — ■ N \ S _.. ... .-- ;.v - — A, \, No 76 \ — ^ .?. ^*' -- ... "' ^ t^,/- //£AT TREfiH'nENT IN CONES. H[/\T TREfiTnENT IN CONES. CM 08 Ob Of Ol I 3 S 7 9 II n IS" 010 08 0b Of ai I 3 5 7 9 II 13 S 0^ 20 «5> /o § %20 ^ 20 « /o ^' o I C; 20 I ^ /o % A No fii \ a.^ s .'' ... "^ rrr rrr '^^^ A No 84 > S M - - rr rr f«-<; A , [Noj8£ > h-i^ ... S 1 ... T"" A 1 Horn 1 "" ^"'** ■— -- «.^ s ^ BAa ... - •-- ... ... //EAT TREfiinENT IN CONES. HEAT TREATMENT IN CONES. 296 DIVISION OP MINES AND MINING Absorption and linear shrinkage curves for clays of class G. ft; I i 0100806 Of OZ / J S 7 9 // 13 /r I I 30 20 10 3^ zo 10 3d 20 10 No 14 5 -. A N. 1 1 \^ _> ... -S --- --" ""* <. — No 15 A 1 \ ^ .S- ,'• ■~ r» < -- - y> No 19 7 A \ _ S *M. HEfiCT TREPJnENT IN CONES. s 5 10 ^ zo lo ^ 20 •« t" 10 lo I 5s 10 % ^ 0)0 08 Ob 0^ OZ / 3 S 7 9 II 13 /£- A_ ^ d^t — - .5. — --- s-t A TTZ No 25 S — - 's ■■ i>— « No 26 3 ^*^ 5 ^^ ^^ — ... -- -— *^ A No 26 6 -— - • — .?.-- ... -- ... .-• __ — ■ ■— M A ^ No 272 ^ _S . * ■ - ~ /VEAT TREAmENT INCOMES. b. Dense-Burning, Less Than 6% Apparent Porosity Between Cones 10 and 15. 7. Mainly Medium to High Strength. No. 13 (p. 163). Riverside Conntv. Alberhill C. & C. Co. "Extra Select :Main Tunnel." See also No. 15 and 29 in class 2. This clay is hand sorted from the main tunnel fireclay bed, in order to prepare a grade for the market that has better fired colors than the run-of-mine material, but for some undetermined reason the sample is distinctly inferior as to color, compared to No. 15 and 29. It is used principally in the manufacture of art tile, and to some extent in firebrick. It has excellent plasticity, medium dry strength, and a sandy, open texture in the drv condition. It contains 2.6' r of -|-200-mesh sand. The colors are: dry, 17'"^f; wet, 17'"'b; cones 010 to 06, ll'f; cone 01, 17"f; cones 02 to 18, 17"'19'"f. Finger-nail hardness is developed below cone 010, and steel hardness is approached at cone 7, but vitrification is not complete until cone 15 is reached. The total linear shrinkage, plastic basis is 14.5% at cone 15. The softening point is cone 29-30. The best firing range is from cone 7 to cone 15. .Vo. 55 (p. 203). San Diego County. Near Carlsbad. Pacific Clay Products Co. "Kelley Ranch White." Tliis is a butf-burning clay with excellent plasticity, suitable for the manufacture of face brick and fire brick. It contains 2.6/r of +200-mesh sand, has medium dry strength, and in the dry state it is soft, fine-grained, and dense. The colors are: dry, 11"; wet, 5"; cones 010 to 01. 7"f; cone 02, 5"f; cone 1, 9"f ; cone 3, 13"f ; cones 5 and 7, 17"f ; cones 9 and 11, 17"d; cone 13, 15"d. A pleasing assortment of buffs, creams, and yellow- browns is obtained by varying the firing conditions. Finger-nail hard- ness is obtained below cone 010, and steel hardness develops at cone 1. The fired structure is sound, fine-grained, and above cone 1, it is stom-. CLAY RESOURCES AND CERAMIC INDUSTRY 297 The total linear shriiikajie, ])]astie basis, at cone 15 is 17.99r. The softeninff point is cone 29. The best firinfj range is from cone 1 to cone 1"). Xo. 56. German fireclay, used by Atlas Fire Brick Co. This is a fine- ll'd ; cones 7 and 9, 17'"d ; cones 11 and 13, 17'''b. Steel hardness is developed at cone 02. Less than 10% absorption appears at cone 1. The fired structure is sound and stony. Slight blistering appears when fired under neutral or reducing conditions to cone 11 and 13. The fired surface texture is slightly rough. The maximum total linear shrinkage, plastic basis, is 18.9%, at cone 9. The softening point is cone 28-29. The best firing range is from cone 02 to cone 9. No. 204 (p. 151). Calavera.s County. Valley Springs. California Pottery Co. "Blue Plastic." The properties of this clay are closely similar to those of No. 203, in class 14, but it contains less iron, which results in lighter fired tones, and in greater refractoriness. It contains 1.0%, of +200-mesh material. The colors are: dry, 17"d ; wet, 17"b; cones 010 to 04, 9"d ; cones 02 to 7, 13"d ; cone 9, 15"d. The total linear shrinkage, plastic basis, is 18.4%, at cones 11 and 13. The soft- ening point is cone 27. This is an excellent clay for buff-burned face brick and roofing tile. No. 213 (p. 59). Amador County. lone. Eckland pit. This is a buflF-burning clay with smooth and strong ])lasticity, and medium-low dry strength. In the dried condition it is medium-hard, fine-grained, and close-textured. The residue on 200-mesh is 12.6%. The colors are : dry, 13"d ; wet, 15'' ; cones 010 to 02, ll'd ; cones 1 to 7, 13"f ; cones 9 to 13, 17"d ; strongly nu)ttled with iron specks. Steel hardness is developed at cone 3, and less than 10% absorption at cone 13. The fired structure is sound and stony, except at cones 11 and 13, when a few large cracks appear in the fired test pieces. The surface texture is smooth until cone 9 is reached, when the reduction of the non-plastic ferro-magnesian minerals causes a pitted surface. The total linear shrinkage, plastic basis, at cone 13, is 22.1%. The softening point if ;^00 DIVISION Ol'' MINES AND MINING cone 31. The best firing- range is from cone 3 to cone 8. The clay is suitable for face brick and faience tile mixes, and could be used in some fire brick mixes. No. 229 (p. 174). Riverside County. Alberhill. L. A. B. Co. "No. 7 Pit." This is a buff-burning i)lastic fireclay that is suitable for face brick or fire brick manufacture. There is slight effervescence in hydro- chloric acid. It contains 0.8'/^ of -|-20()-mesh sand. The plasticity is smooth and strong, the dry strength is medium-low, and in the dried condition it is medium-hard, fine-grained and close-textured. The colors are : dry, 9"d ; wet, 7"b ; cones 010 to 06, 5'f ; cones 04 to 3, 5''f ; cones 5 to 9, 17"f ; cones 11 and 13, 17"(1. Steel hardness is developed at cone 1, and less than 10'^{ absorption at cone 9. The fired structure is sound and stony, and the surface texture is smooth. The total linear shrinkage, plastic basis, at cone 13, is 20. 4'/^ . Slight bloating appears at cone 15. The softening point is cone 32. No. 230 (p. 174). Riverside County. Alberhill. G., McB. & Co. East Pit. "No. 9 Clay." This is a buff -burning refractory clay with smooth and strong plasticity, and medium-high dry strength. It con- tains 2.0 9( of -|-200-mesh sand. In tlie dried condition it is medium- hard, fine-grained, and close-textured. The colors are : dry, 13""d ; wet, 17""d; cones 010 to 04, pinkish white; cones 02 to 7, yellowish white; cones 9 and 11, 19"f ; cone 13, 17'"d. Steel hardness is devel- oped at cone 02, and less than 10% absorption appears below cone 5. The fired structure is stony, and all test pieces are broken into two or more pieces by fracturing. The total linear shrinkage, plastic basis, at cone 13, 17.5 % • The softening ])oiut is cone 32-33. The clay can not be used alone, but when mixed with non-plastic material, it is an excel- lent clay for face brick, fire brick, and terra cotta. No. 245 (p. 52). Amador County. lone. Core drill hole No. 55-1. Arroyo Seco Grant. This is a buff-burning clay with good, but sticky, plasticity and medium dry strength. In the dried condition it is soft, friable, fine-grained, and close-textured. The colors are: drv, buff- Avhite; wet, 17""f; cone 1, 19"f; cones 5 and 9, 17"d; cone 13, 15"i. Steel hardness develops below cone 1, and less than 10% absorption between cone 1 and cone 5. The fired structure is sound and stony, and the surface texture is smooth. The total linear shrinkage, plastic basis, at cone 13, is 19.0% . The softening point is cone 30-31. It could be used in face brick, terra cotta, tile, and fire brick. - iVo. 545 (p. 52). Amador County. lone. Core drill hole No. 55-3, Arroyo Seco Grant. The plasticity is good, but sticky ; the dry strength is medium, and in the dried condition it is soft, friable, fine- grained, and close-textured. The colors are : drv, gravish white ; wet, 15"'"f; cones 1 and 5, 19"f; cone 9, 17""f; cone 13, 17""d. Steel hardness is developed below cone 1, and less than 10%) absorption is jiroduced between cone 1 and cone 5. The fired structure is sound and stony, and the surface texture is smooth. The total linear shrinkage, plastic basis, at cone 13, is 16.7% . The softening point is cone 29. No. 247 (p. 52). Amador County. lone. Core drill hole No. 55-2, Arroyo Seco Grant. This is similar to No. 246, but has greater shrinkage, a higher softening point, and effervesces slightly in hydro- CLAY RESOURCES AND CERAMIC INDUSTRY 301 chloric acid. Tin* total liiicai- shrinkage, plastic basis, at cone 13, is 19.5Vc. The softenino: point is cone 32. No. 2iS (]). 52). Amador Connty. lone, ("ore drill hole No. 56-1, Arroyo Seeo Grant. Tlic plasticity is good, the dry strength is medium high, and in the dried condition it is medium-hard, fine- grained, and clo.se-textured. A ]>art of the sample consists of soft grains of partly kaolijiized matter tluit is not rendered i)lastic by the usual methods of preparation. This results in a heterogeneous structure. The colors are: dry, 17'"f; ^vet, 17"'d ; cones 1 and 5, 17"d; cones 9 and 13, 17""h. Steel hardness is developed below cone 1, and less than lO'/r absorption appears between cone 1 and cone 5. Blistering is noticeable at cone 13. The maximum total linear slirinkage, plastic basis, is 21.1 /r, at cone 9. The softening point is cone 30-31. It is suitable for the manufacture of terra cotta and tile, but is not suitable for making a good fire brick. No. 249 {\).b2). Amador County, lone. Core drill hole Xo. 56-2, Arroyo Seco Grant. This is very similar to No. 245, and does not require a separate description. The total linear shrinkage, plastic basis, is 18.2'/ at cone 13. The softening point is cone 30-31. iVo. 55c? (p. 52). Amador County, lone. Core drill hole No. 57-3, Arroyo Seco Grant. This is similar to No. 136 (class 8) and 240 (class 4), with the differences as noted. There is slight effervescence in hydrochloric acid. The colors are: dry, pinkish white; wet, yellow- ish white; cone 1, nearly white; cones 5 and 9, 19"f; cone 13, 17"'b. Steel hardness and less than 10/r absorption are developed between cones 1 and 5. Xo firing cracks were noted. The total linear shrinkage, plastic basis, is 21.5%, at cone 13. The softening point is cone 31-32. No. 254 (p. 52). Amador County, loiu'. Core drill hole X"o. 57-4. Arroyo Seco Grant. Tliis sample contains more coloring matter and more non-plastic ferro-nuignesian minerals than No. 253. There is slight effervescence in hydrochloric acid. The i)lasticity is good, the dry .strength is medium, and in the dried condition it is soft, fine- grained, and open-textured. The colors are: drv, 17"f; wet, 17"'f; cone 1, 15"f ; cone 5, 17"'d ; cone 9, 17""d ; cone 13, 17"'b. Steel hard- ness appears below cone 1, and less than 10% ab.sorption is developed between cone 1 and cone 5. The fired structure is sound and stony, except that at cone 13, one large crack developed in the test piece. Blistering is noted at cone 13. The maximum total linear shrinkage, pla.stic basis, is 21.6' v, at cone 9. The softening point is cone 31. This is a suitable clay for face brick, terra cotta and tile. No. 271 (p. 163). Riverside Countv. Alberhill. Alberhill Coal & Clay Co. "Lower Tunnel, Hill Blue." See also No. 9 and 272 in class 6, and No. 274 in this class. The plasticity of No. 271 is smooth and strong, the dry strength is medium-high, and in the dried condition it is hard, fine-grained, and close-textured. It contains 2.0% of -|-200- mesh sand. There is slight effervescence in hydrochloric acid. The colors are : dry, 13"" f ; wet, 5""f ; cones 010 to 9, 17"f ; cones 11 and 13, 21""d. Steel hardness is developed at cone 1, and less than 10% absorption at cone 5. One or two of the test pieces show small cracks, otherwise the fired structure is sound and stony, and the surface texture 302 DIVISION OF MINES AND MINING is siuootli. Tlie total linear slirinka ("(.imtv. Albcrliill. A. ('. & ('. Co. "Upper Tunnel Hill Blue." See also No. 9 and 272 in class 6, and No. 271 above. No. 274 is intermediate between No. 271 and 272 in its content of sand and its ceramic properties. The dry strength is medium. There is no effervescence in hydrochloric acid. Tlie sample contains 11.4% of -f-200-mesh sand. The colors are: dry, I'^'^f ; wet, ir)'""b; cones 010 to 06, 15"f ; cones 04 to 9, 17"f ; cones 11 and 13, 17"d. Steel hardness is developed at cone ;1, and le.ss than 10% absorp- tion at cone 9. The fired structure is sound, sliglitly heterogeneous, and the surface is slightly rough. The total linear shrinkage, plastic basis, at cone 13, is 19.8%. The softening point is cone 30. Tliis is a suitable clay for fire brick, face briclv and terra cotta. c. Dense-Burning, Less Than 6 Per Cent Apparent Porositv Between Cones 5 and 10. 8. Medium to High Strength. No. 121 (p. 53). Amador County, lone. Arroyo Seco Grant. Jones Butte. Leased by Stockton Fire Brick Co. "Unctuous Clay." The available quantity of this clay is insufficient for commercial production, but a sample was tested as a matter of general interest. It has a smooth and strong plasticity, medium dry strengtli, and in the dried condition it is medium-hard, fine-grained and close-textured. The colors are : dry, nearly white ; wet, 21'"f ; cones 010 to 06, pinkish white ; cones 04 to 9, yellowish white ; cones 11 and 13, I'^'^f . Steel hardness is developed at cone 04. Less than 10.0% absorption appears at cone 5. The fired test pieces are stony below cone 11, and glassy at cone 11 or above. They are sound, but seriously warped. The total linear shrinkage, pla.stic basis, at cone 13, is 25.6%. The softening point is cone 33. The clay is closely similar to some of the varieties that are mined at Lincoln, Placer County, especially No. 146, post. No. 124 (p. 56). Amador County. lone (Carbondale). Leased by G. A. Starkweather. "Yarn No. 1." This is a piuk-and-cream burning clay with smooth, moderately-strong plasticity and medium dry strength. It contains 1.0% of +200-mesh sand. The dried condition is soft, "soapy," fine-grained and open-textured. A strong tendency to warp and to laminate was noted. Tlie colors are: drv, 2V"i; wet, 21''"d; cones 010 to 04, 9'f ; cone 02, 17"f ; cones 1 to 1, 17"d ; cones 9 to 13, 19"f. Steel hardness is developed at cone 1. Less than 10% absorption appears at cone 3. The fired structure is generally sound, but a few pieces split in firing. The total linear shrinkage, plastic basis, at cone 13, is 20.8 7('- The softening point is cone 32. The best firing range is above cone 1. The claj'' is suitable for fire brick, terra cotta, stone- ware, etc. A'o. i55 (p. 58). Amador County. lone (Clarksona). N. Clark and Sons. "Dosch." This clay has been well knoAvn for many years in the pottery, stoneware, and terra cotta industries. It contains but 1.2% of -j-200-mesli sand. It is smooth and has strong plasticity, medium dry strength, and in the dried condition it is medium-hard, fine-grained, CLAY RESOURCES ANI> , ifiRAMIC INDUSTRY 303 aiul close-textured. Tlie colors are: dry, yellowish Avhite; wet, 17"'f; eone 010, 17"f, becomin}? nearer to wiiite with increasinrr firing tem- l)erature. approximating? 19"f at cone 3; cones 11 -and 13 (flashed) 17"'. Steel hardness ai>pears at cone 1. and less tlian 10',' absorption at cone 3. The fired structure is sound, stony and smooth-textured. The maxinmm total linear shrinkage, plastic basis is 21.0% at eone 13. Slio-ht bloating was noted at cone 15. The softening point is cone 31. The l)est firing range is from eone 1 to eone 13. Tlie clay can be ca.st and jiggered. No. lie (p. 156). Placer County. Lincoln. Lincoln (May Products Co. "Xo. 1-6." This is the best known variety of Lincoln clay at the present time. It is shipped to all parts of the Pacific Coast for use iu stoneware, pottery, faience tile, terra cotta, fire brick, and other pur- poses. It is an excellent clay for casting and jiggering. The plasticity is smooth and strong, and it contains but 0.6% of --f-200-mesh sand. The dry strength is medium, and in the dried condition it is soft, fine- grained and close-textured, with a talcv feel. The colors are : dry, buff- white ; wet, 17''d ; cones 010 to 04, ll"f ; cone 02, 13"f ; cones 1 and 3, 17"f; cone 5, 17'f; cones 7 and 9, 21"'f; cone 11, 17""f; cone 13, 13""f. Steel hardness is developed at cone 1. Less than 10% absorp- tion appears at cone 3, and vitrification is complete at cone 9. Slight blistering is noticeable on test pieces fired under reducing or neutral conditions at cones 11 to 15. The fired structure is sound and stony. The maximum total linear shrinkage, plastic basis, is 21.5%, at cone 11. The softening point is cone 31-32. The best firing range is from cone 1 to cone 11. The long vitrification range, the excellent plasticity, and the ability to withstand abuse in drying and firing, are the important advantages that this clay possesses to a greater degree than any other clay in the state that is available in commercial quantities to the entire iiulustry. The same is true of Xo. 280, see po!il. No. 147 (]). 156). Placer County. Lincoln. Lincoln Clay Products Co. "Xo. 7." This clay is very similar to Xo. 146, but fires to slightly darker tones. It is used in faience tile, face brick, and sewer-pipe mixes, but is not quite as suitable for casting and jiggering as No. 146. The colors are: drv, 9"d ; wet, 13'"b; cones 010 to 04, 5'f ; cones 02 and 1, ll"f; cone 3, i5"f; cone 5, 17"f; cones 7 and 9, 17'"f; cone 11, 17""f; cone 13, 13""d. Steel hardness is developed at cone 1, and less than 10% absorption is developed at cone 3. Vitrification is com- plete at cone 9 — , and blisfei-ing is well develojied at cone 13. The maximum total linear shrinkage, plastic basis, is 21.4%, at cone 11. The softening point is cone 31. No. 1.51 (p. 156). Placei- County. Lincoln. Lincoln Clay Products Co. "Wa.shed China Clay. ' ' This sample was supplied by Mr. Dillman from a warehouse stock of some material that was prepared some years ago by washing the Xo. 1-6 (sample X'^o. 146) clay, in an attempt to produce a china clay for the local market. The color was improved slightly by this treatment, but not sufficiently to permit the use of the clay as a substitute for English china clay, and the shrinkage was increased greatly beyond the already high shrinkage of the crude clay. Slight blistering appears at cone 11. The maximum total linear shrink- age, plastic basis, is 25.6%, at cone 9. The softening point is cone 30. ^04 DIVISION OF MINES AND MINING There is slifi:lit effervescence in liydrochloric acid. Sfuiniiiiii^- was not noticed, as in the majority of the crude Lincoln and lone clays, but no special tests Avere-inade to determine if washing? iuid completely removed the vaiuidium salts which have been stated to be the cause of scumming of these clays/ No. 152 (p. 147). Placer County. Lincoln. Clay Corporation of Cali- fornia. This samjile of plastic fire clay, toji'cther with Xo. 15:} (class 7), was taken from the i)it a])pi-oach durinf>' the i)relimiiuiry develop- ment of this ])roperty. Tlie test results should be comi)ared with those of Xo. 280, which sample was sui)plied by the company from the ware- house after full-scale production had been i-eached. Xo. 152 has excel- lent plasticity, medium-hijih dry streno'th, and in tlie dried condition it is soft, fine-xcellent, the dry strength is medium, and in the dried condition it is medium-hard, fine-grained, and close-textured. The colors are: drv, 17"f; wet, 17"d; cones 010 to 1, ll"f; cones 3 to 9, 17"d; cones 11 and 13, 17""d (flashed). Steel hardness is developed at cone 04. and less than 10*;, absor])tion apjiears at cone 3. The fired structure is sound and stony, excei)t that a few small cracks ai)peared in some test j)ieces during firing. The fired sur- face texture is smooth. Slight blistering is noticeable at cone 13. The maximum total lineai- shrinkage, plastic basis, is 23.6%, at cone 13. The softening point is cone 32-33. No. 175 (p. 65). Butte County. Oroville. Table ^Mountain Clay Products Co. This is a plastic, buff-burning clay from the lone fornui- tion. The plasticity is smooth and strong, the dry strength is nu'dium, and in the dried condition it is soft, "talcy, " fine-grained, and close- textured. It contains 2.4^, of -|-200-mesh sand. The colors are: drv, ]7"f ; wet, 15"d; cones 010 to 04, 7'f ; cone 02, ll'f ; cones 1 to 5, 15'd; cones 7 and 9, 15"d ; cones 11 and 13, 17"'b. Steel hardness is devel- oped at cone 02, aiu1 less than 10*^,' absorption at coiu' 1. The fired structure is stony, and the surface texture is exceptionally smooth. Up to cone 7, all test pieces are sound, and at cone 7 and above, each test piece is fractured into two or more fragments. The total linear shrink- age, i)lastic basis, at cone 13, is IS. 9'^ . Bloating is ]ironounced at cone 15. The softening point is cone 30-31. The best firing range is from 'See Currv, E. R., Notes on Green Scummins: .Tour. Am. Cer. Soc, Vol 9, p. .^92, 192G. (LAY RESOURCES AXD CERA^flC INDUSTRY 305 cone 02 to I'onc l:?. Since tlie sainplc was taken near the surface durinf; tlic |)reliniinary developnieiit of the i)roi)ertY. it may not be representa- tive. The clay is suitahh> foi- the manufacture of fire bi-ick, roofing- tih', terra cotta, and for any pottery oi- decorative tih' in whicli the l)ulf color is not objectionabh". No. 201 (p. 69). Calaveras Count \. llelisma. This is a plastic, buft'-burning clay from the lone formation. The plasticity is smooth and strong, the dry strength is high, and in the dried condition it has finger-iuiil hardness, is fine-grained, antl close-textured. The sample contains 11.4'/^ of +200-mesh sand. Tiie colors are: dry, 17'"f; wet, 17"'f ; cones 010 to 04, ll"i; cones 02 and 1, 17''d; cones 3 to 6, 17"b ; cones 9 to 13, 17'". Steel hardness and lO'^ absorption are developed at cone 04. The fired structure is tough, stony aiul .sound, excei^t at cones 11 and 13, where large cracks appear. Vitrification is complete at cone 9, above which temperature bloatnig begins, but the softening point is cone 28. The maximum total linear shrinkage, plastic basis, is 21.5% at cone 9. The clay is suitable for the uuniufacture of face brick. No. 252 {\i. y)2). Amador County, lone. Core drill hole No. 57-2, Arroyo Seco Grant. Tliis sample i.s similar to No. 245 and 249, in class 7, with the important diiil'erences as noted below. The colors are: dry, 17"f ; wet, 17"'f ; cone 1, 13"f ; cone 5, 17"'f ; cone 9, 17'"d ; cone 13, 17""d. Slight blistering is noted at cone 13. The maximum total linear shrinkage, plastic basis, is 22.4%, at cone 9. The softening point is cone 32-33. Ao. ^80 (p. 147). Placer County. Lincoln. Clay Corporation of Cali- fornia. See also No. 153 and 146. The plasticity is excellent, the dry strength is medium-high, and in the dried condition it is medium-hard, close-grained, and fine-textured The bonding strength, with 50% (3ttawa sand from — 20 to +30-mesh, is 211 lb. per sq. in. It con- tains 11.2% of +200-mesh sand. There is slight effervescence in hvdrochloric acid. The colors are: dry, nearly white; wet, 17"'f ; cones 010 to 04, 7'f ; cones 2 to 5, 7"f ; cones 7 to 13, 21""d. Steel hardness is developed at cone 02, and less than 10% absorption at cone 1. The fired structure is stony, and is sound up to cone 9. At cones 11 and 13, a few cracks are noted, and there is slight blistering. The surface texture is smooth. The maximum total lineai' shrinkage, plastic basis, is 20.3%, at cone 9. The softening point is cone 30-31. The clay is used by the Stockton Fire Brick Co. in the manufacture of fire brick and refractory cement, aiul is marketed to tile manufacturers and others. 20—54979 306 DIVISION OF MINES AND MINING TABLE No. 20. II. Buff-Burning Clays. A. Refi'actory clays, softi'iiing point cone 27 + . b. Dense-burning, less than 6''/< apparent porosity between cones 10 and 15. 7. Mainly medium to high strength, but also including some clays of low strength. Clay No. % S.W. % P.w. 1.3 12.4 15.9 3!t 14.7 18.1 .■iC 13.1 10.9 8U 17.0 24.8 83 12.8 17.5 85 16.3 17.7 101 16.5 17.1 110 20.3 20.6 i:{;i 22.4 21.5 149 18.6 18.8 15.3 20.7 21.8 156 20.3 17.1 204 17.1 17.7 213 15.5 23.8 229 17.0 18.4 230 15.4 18.4 245 19.6 17.2 246 15.2 17.2 247 18.1 20.7 248 27.3 16.4 249 18.7 16.8 253 20.2 20.5 254 19.6 21.8 271 17.0 17.5 274 19.1 15.4 % W.P. 28.3 32.8 24.0 41.8 30.3 3 4.0 33.6 40.9 47.9 37.4 42.5 37.4 34.8 39.3 35.4 33.8 36.8 32.4 38.8 43.7 35.5 40.7 41.4 34.5 34.5 D.T.S. 255 257 628 Erratic 230* 245 355 200-400 140 260 616 670 280 105 181 ±419 O O r o o O 328 309 ±680 ±395 204 ±251 531 444 % D.V.S. 22.4 25.5 26.4 27.1 22.8 28.6 30.0 34.2 34.6 32.5 33.7 36.1 29.9 24.7 29.7 27.4 34.5 26.8 30.4 48.4 33.8 33.3 32.2 30.4 35.1 % D.L.S. 7 7 8 8 7, 8 9 10 10.4 9.8 10.2 10.8 9.1 7.6 9.1 8.3 10.4 8.2 9.2 14.1 10.2 10.1 9.7 9.2 13.4 Soften- ing pt. in cones 29-30 29 27 33 29 31-32 30 32-33 33 31-32 30 28-29 27 31 32 32-33 30-31 29 32 30-31 30-31 31-32 31 31-32 30 * Bonding strength with 50% Ottawa sand ( — 20- + 30-mesh) is 56 lb. per sq. in. c. Dense-burning, less than 6% apparent porosity between cones 5 and 10. 8. Medium to high strength. Clay No. 121 124 136 146 1^7 1^1 152 157 175 201 252 280 ; S.W. 27.4 17.4 20.9 19.7 20.5 29.5 26.8 20.2 15.4 23.2 17.6 19.5 % P.W 20. 19. 20. 19. U 28. 22. 22. 17. 18. 21.1 20.7 % W.P. 48.1 37.0 41.0 38.8 39.2 37.9 49.4 42.3 .'!2.5 41.4 38. 7 40.2 D.T.S. 3 40 219 270 239 284 301 710 37!t 369 89 4 296 466* % D.V.S. 45.3 29.4 35.4 34.0 35.6 43.4 43.0 33.2 27.5 40.2 29.2 33.1 % D.L.S. 13.2 8.9 10.6 10.3 10.7 12.8 12.8 10.1 8.3 11.9 8.9 10.0 Soften- ing pt. in cones 33 32 31 31-32 31 30 33 32-33 30-31 28 32-33 30-31 • Bonding strength with 50% Ottawa sand ( — 20- -f 30-mesh) is 211 lb. per sq. in. f/c S.W. = Per cent shrinkage water. % P.W. = Per cent pore water. f/r/W.P = Per cent water of plasticity. D.T.S = Dry transverse strength, pounds per square inch, without sand. % D.V.S. = Drying shrinkage, per cent dry volume. % D.L.S. = Calculated linear drying shrinkage, per cent dry length. CLAY RESOURCES AND CERAl^fTC TXDUPTRY 307 2 ^ « •' « S > a * E £ P S -2 _2 . = -^ -= .r 5 'c 'E "^ -o ^ - -^ at -^ z Id u. 5 V. 2 _j ■n ^ « < l" — t- — . hr o bC -f" -^ ^ ■ — 3 3 n -o -O I g Q .*. f3 «a ' c^ j.-^ S o .^=^' " -< ktirf t t t < CO WT >C «M I ' "^ 1 1 1 1 . ■ ■ ■ 1 ie4< '< I o: -^ I o CO c o O ^i OCICl 'CS'J'CiCOTfC^»0 0'»«-f'C^I-^CC>OW:cDOcOOC^HMCO<;©OOcO(N05COOO — t>- ^i «»oh- icoc^O'^'-ooc^ •^cpo 'NOc^t^t^fMcitDCOO OOi ^COO »o CM C^l — — -- „ c^ ■ 1 1 1 1 iCMC — COCMOOO — 1-*"^ ^.» t^cDC^-^-C^OOCOOOO — ic-«»«i-«eD • •III iCM*e}4 OCMO'^OCOCOO'^ CM g ?0 •<»' O »r5 CO lO -^ OS CM 05 -H OS i t 1 1 » 1 Ci) CM '^ CO CO CO CO CO ■* CO CO ^^ c o O coooooo'C^iic«ooc'icoc^Jco5DTt"r-coO(M^r-ooi--'M — »oroooocc— cooot-* C5 — ' ..^ 00'^»CW500CCt^OS-^T'«OOCOOOOOiOCO O r* lO t^ woo -^ C5 ^QO — Oi CDOO CM • I C0C0^MC0(M-t<-'fCit^:O'-«O;C»C0 • 1 ^^ ^ -^ ^ CM CV| ^ CO fO oseait^o«pcoocoecocO'*^oico CMCM<— •MCMC'I'M.— i^^CMCM'— "C^CMCM Q0CiCr:C0(Mr^-^Cnrj':0C^)^00OO ' 1 1 t ■■-J'lCOO'— Oi-n''-fC»C:iOCCoO ' ' ' 1 >OCO!:OCDiO»0'OOI--;0000 CM^CieOCMCviCMCCCOCOCMCO o CJ^O--i2CMI^a;CMt*0(MCMt^-rt«0> — — COCM— COW01(NCM^«M — CMCMicooe-^CMco^oocMcocoo CMCO-HCOCMC-ICM-MCOC-KM— CMCOCO or^i^^ot^cc^ic^ioO'— 'ooooocoo»o — '^ ^ " — " •— (M — ^ C cocv?(^^cococococo:0'^^M(^!'^^^coM eoiooco-for^oicpoc'jcc-rcoi^o 0»0 CM O -^ CO »CCM O CO-t» ^ 00 CM iCCOCOOt^t-iCoOCOCO-f-fiMTfOCS I • 1 • 'cooiicr— cioo'XJco-^ooo-f -r O c-rr'-c-oc'ios CO CM CO CO CO CO CO CO CO CO CO ^ CO CO CO QO CO ^ »r3 oo O oi O CO >c >0 -^ C: '--M o; ! ! ClCOt^(3iC0iO ' i I I I I^O^iOOSr^-^CMOcDOTt^ 1 > 1 1 1 icO-^'-<»0»C'*COCDOOOSCD<0 1 CM "CO ^ -+ CMCO" Wt-^CO O CDCM b- U5 , o o u 5 O .o^: '■'-H — 0^ '-HrOiCOOCOOOO^CO^iC»CO'— CMCO-^'rJ''rr--t*-rt'»/3lOt^t^C-lCMCO'rrM'»ClOlOt--OiOOO _ — — ««„C^, C^ICM 6? 308 DIVISION OF !\nNES AND MINING A lisc)i-]il idii ami linear .shi'iiikagc cui'vcs for clays of class 010 08 06 O^OZ I 3 S 7 9 II 15 15- S I tt: S -J »^ •« ^" I I *9 20 10 20 10 o 20 10 20 10 No 13 N ^ — -^ — • _s _ » .- -- -- -- -- >^ .A No 39 V ^ — ^ -■*■ w * -• • s -- -- -- -- — 's No 56 _ A. s. ***■ ~'^ " rr =^ ►-^ V A No 60 S \ • • w * -"■ ~ " -- -- -- -- •■ ^ ^ ^ ^^ ft: //fAT TREATneNTlNCOfiES. CIO Oaob Cf OZ I 3 S 7 S II 13 IS" 20 10 20 10 o 20 10 20 10 HEAT TRFATHFNT IN CONES _ No, 83 \ -^ »** — .. _s ^^ — -^ A No 85 ^^ "V ^ ^ =« «•* _S_ ^' — S A No 10) — •V ^^ S .. M » — — — *<. s — — < No II S Si- ., .* — - -- — ^H, ^_ -- ,s. ^^ "S "" — _ ^ or OK) 08 Ob Of OZ I 3 5 7 S II 15 IS- I I I 20 10 O 20 /O O 20 10 O 20 10 O ■~" A S \. No. 13 3 \ V ... ... -- ... -, ".^ .- _S_ -- .-' ' V — — - ^ / ^ A No. H 9 \ N k n* .S ^ ^^ -- '• - ^ — ^ / — ^ Sn- No 15 3 \ __ »> ^ ^ ^ „ _. _S. ^•l* -- -' ^ \ ■*-* No 15 6 A V ^«j r* __ JS. ^* ^ ==^ Z^ . "*^ ^ (XiOBObOfOll 3 5 7 9 II 15 /T /^£AT TREATMENT IN CONES HEAT TREATMENT IN CONES. CLAY RESOURCES AND CERAMIC INDUSTRY 309 Absorption and linear shrinkase curves for clays of class 7. 010 08 06 Of OZ I 3 5 7 S II 13 ir HEfiCT JREfirnENT INC0NE5. i tt: -J OlOOSOb m OZ I 3 5 7 9 II 15 /r 20 10 o 20 10 a 20 10 o 20 to ° HE A T TREAinEN T IN CONES. No 25 3 1 — ^ Srf' ^— 'i ^S — No Z5 4- \ ^^ — — .S — r' \ ^ - No 27 1 ""^ ^ V _^ -.- _s -- *"• r*. V. No 27 4 — — A . _ •V „ — s — — - ^ ^ 310 DIVISION OP MINES AND MINING m 5 ^ a 5 o ^ S o o u o m > ;-< 3 o a> Ul m u a o b. en S ^ o ( / \ • \ 1 V \ 1 1 t- / M t^ 1 1 i t 1 \ n / \n lo 1 1 1 6 Z t / ^ / Z 1 1 / c5 Z 1 ( i • « / \ \ / / \ \ / \ > X^ V / * J / \ / / \ \ / 1 1 / r \ < lo'i i < :li Streiij^th. Xo. 19 (p. 16:1). Kiversidp (\)nnty. Albcrliill V. & V. Co. "Yellow Strippinth to i)enuit its use in a superior grade of coiiunon l)i-ick, which is marketed undei- the name of "Diamond Brand." The dry stivngth is medin)u-lii.') (\). M\). Kivcrside {'()iint\. Alberhill. (1.. McB. & Co. No. 94 is the "West Blue" and No. 95 is the "Select West Blue" clav. These two samples should be compare(_l with No. 25, the "West Tunnel Blue" of the Alberhill C. & C. Co., and not with their "West Blue" (No. 23, class 5) and "Select West Blue" (No. 16, class 10) varieties. No important differences betAveen No. 94 and 95 were dis- 312 DR'^ISION OF MINES AXD MIXIXO closed by the testiiifr, but they both have a hipher proportion of sand and a lower percentage of iron than No. 25, Avhicli results in a largre difference in the ceramic properties and uses of No. 9-t and 95, com])ared with No. 25. No. 94 contains 24.2^f, and No. 95 contains 27.6'/; of +200-niesh sand, compared to 18.8'/f for No. 25. The plasticity of No. 94 and 95 is good, the dry strength is medium, and in the dried state they are soft, medium-grained and open-textured. The colors are: dr^', 17""f ; wet, neutral gray; cones 010 to 02, l."]'"d; cones 1 to 13, 13""d. Abundant jiarticles of ferro-magnesian minerals give a pleasing granitic texture to the test pieces fired above cone 1. Finger- nail hardness ai)]iears below cone 010. and steel hardness at cone 1. Absorptions under 10*^^ are obtained at cone 3. Bloating is pronounced at cone 11, especially when a reducing flame is used. No. 95 has lower shrinkage and lower absorption at cone 9 than No. 94. The maximum total linear shrinkage, plastic basis, is at cone 9. and is 11.7/^ for No. 94, and 10.5 'y for No. 95. The softening points are cones 17 and 18, respectively. The best firing range is from cone 1 to cone 9. No. 94 is used in tile bodies, and No. 95 in terra cotta bodies. Ao. 5.9 (p. 171). Riverside County. G., McB. & Co. "Tile Clay." This is a red and tan-burning plastic clay that is used for the manu- facture of roofing tile, face brick, and similar products. There is slight effervescence in hydrochloric acid. It contains 30.89c of -)-200-mesh quartz-mica sand. The plasticity is excellent, the dry strength is medium high, and in the dried condition it is medium hard, medium- grained, and open-textured. The colors are: dry, 13""d; wet, 17""; cones 010 to 02, 7"b ; cone 1, ll"b; cones 3 to 11, 13"b; cone 13, 15". Mottling from the presence of ferro-magnesian minerals is pronounced above cone 5, giving pleasing textural effects. Finger-nail hardness is developed below cone 010, and steel hardness develops at cone 5. Absorjitions below 107c are not obtained until cone 11 is reached. The fired structure is sound and stony and the texture is rough. The total linear shrinkage, plastic basis, at cone 13, is 11.99^ . The softening point is cone 26-27. The best firing range is from cone 02 to cone 9. No. 114 (p. 90). San Bernardino County. Near Rosamond. Titus deposit. This is a buff-burning clay with fair plasticity, medium dry strength, and a medium hard, medium-grained, dried condition. It has not been produced steadily, but tests have been made by various clay manufacturers. The colors are: dry, grayish white; wet, 23"'"f; cones 010 to 3, 17"f ; cones 5 to 9, 17'"f ; cones il and 13, grayi.sh white. Finger-nail hardness is developed below cone 010. and steel hardness appears at cone 1. The fired structure is sound, homogeneous, stony, and without warp. The surface texture is slightly rough. Above cone 11, scattered iron specks become noticeable. Absorptions below 10/^ are obtained at cone 9. The total linear shrinkage, plastic basis, is 6.9%, at cone 13. The softening point is cone 17-18. The clay might be useful in stoneware, vitrified floor tile, and similar mixtures, altliougii for the highest purposes, wasiiing would be necessary to remove the non-plastic coloring impurities. No. 13'i (p. 58). Amador County. lone (Clarksona). N. Clark and Sons. "Dosch Stripping." This is a sandy yellow-burning clay with good plasticity and medium-high dry strength. It contains 18.0% of CLAY RESOURCES AND CERAMIC INDUSTRY ^H Tj -|-2()()-HiP.sh sand. In the dried condition it is medinm hard, fine- •rraincd, and close-textured. The colors are: dry, lo"d; wet, 15"1) ; cones 010 to f), 9"d ; cone 7, 19"b. .Steel hardness (lev(dops at cone 02, and less than 109' absorption at cone >]. Tlie fired structure is sound, g:rannlar and roup^h-textured. A vesicular structure develops above cone 7. Tlie maximuni total linear shrinkaofe, plastic basis, is 15.1% at cone 7. Tliis niatci'ijd is used in sewer-])i])(» mixes. Xo. 168 (p. 1;)6). Nevada County. Cliica^o Pai-k. Beaser Rancli. Til is is a pink-burninj; clay from near the surface of an undeveloped deposit. The plasticity is smooth, but weak, the dry strengtli is medium, and in the di-ied condition it is medium hard, fine-»rained, and close- textured. The colors are: dry, 17"'f; wet, 17"'d: cones 010 to 06, l.yf; cones 04 and 02, 15'd; cone 1, Wh. The fired colors are ochra- ceous salmons and butTs, which are unusual. No scumminf? or efflo- rescence was noted. Steel hardness is develo])ed at cone 02. The fired structure is .sound, aiul stony, and the surface texture is exceptionally smooth. The total linear shrinka<>'e, ])lastic l)asis, is 8.6% at cone 1. The clay could be used locally for common. brick, and might be u.sed to make an attractive, though unusual, face brick. No. 169 {]). VAH). Nevada County. Pearldale. Sonntag Ranch. This is a buff-burning clay from a surface exposure of an undeveloped deposit. The plasticity is fairly smooth and strong, the dry strength is medium, and in the dried condition it is soft, medium grained, and open-textured. The colors are: drv, 17"f; wet, 17"d ; cones 010 and 08, ll'f; cone 06, i:rf ; cones 04 and 02, 15'f ; cones 1 to 5, 17'f ; cone 7. 17"d; cones 9 to 18, 17"'b, but with a distinctly mottled appearance. Some interesting color etTects for floor tile and face brick can be pro- duced with this clay. Steel hardness is developed at cone 1. Less than 10% absorption appears at cone 7. Slight bloating is apparent from the shrinkage and porosity data at cones 11 and 13, but no loss of shape was noted. The fired structure is sound and stony, and the surface texture is slightly rough. The maximum total linear shrinkage, plastic basis, is 11.1/^ , at cone 9. The softening point is cone 19-20. The best firing range is from cone 1 to cone 9. Xo. 173 ( )). 2;>r)). Yuba County. Smartsville. J. P. Dempsey Ranch. Kaolin itic material from a copper prospect in volcanic rocks. It was not possible to secure a sample entirely free from limonite. The plas- ticity is fair, the dry strengtli is medium, and in the dried condition, it has finger-iuul hardness, is medium grained, and open-textured. A high percentage of non-pla,stic matter is present. The colors are: dry, yellowish wliite; wet, 17'"f ; cone 010, 7"b; fading progressively with increasing firing temperatures to 13'"d at cone 5. Green scumming is pronounced. Steel hardness is developed at cone 04. The fired struc- ture is sound, and fine-granular, except at cone 6, where light super- ficial hair-cracks appear. The surface texture is slightly rough. The total linear shrinkage, plastic basis, at cone 9, is 19.1%. Xo. 255 {\). r)2). Amador County. Tone. Core drill hole No. 57-5, Arroyo Seco CI rant. This is similar to No. 254 in class 7, but fires to darker colors. The plasticity is good, the dry strength is medium, and in the dried condition it is medium hard, fine-grained and open- textured. There is slight effervescence in hvdrochloric acid. The colors 314 DIVISION OF MINES AND MINING are: dry, i)"d; wet, 9"b; cone 1, 9"d; cone 5, 15"d ; cone 9, 17"b; cone 18, 15"i. Steel hardness is developed below cone 1, and less than 10% absorption between cone 1 and cone 5. The fired structure is sound and stony, and the surface texture is smooth. No blistering w^as noted at cone 13. The total linear shrinkage, plastic basis, at cone 13, is 21.6%. The softening point is cone 26. This is a good clay for face brick, roofing tile, and similar products. No. 283-A and B (p. 232). Tulare County. Dueor. W. A. Sears deposit. See also No 284, class 10, and 285, class 5 These are samples of impure kaolin, aiul have fair plasticity and medium dry strength. The dry condition is medium-liard, fine-grained, and open-textured. The colors of No. 283-A are: dry, nearly white; wet, 15'f ; cones 010 to 3, 17"d; cones 5 and 7. 17^1;' cone 9,'l5'd; cones 11 and 13, 13'd. The colors of No. 283-B are: drv, gravish white; wet, 21""f; cones 010 to 02, 17""f; cones 010 to 5, 21'"f; cones 7 to 13, 17"d. The colors are rather disagreeable yellowish buffs, and are irregular. Yel- low scumming is very pronounced. Steel hardness is not developed up to cone 13, the upper temperature limit studied. The fired struc- ture is sound, and there is no evidence of vitrification up to cone 13. The total linear shrinkage, ])lastic basis, at cone 13, is 10.7% for No. 283-A, and 9.7%, for No. 283-B. The softening point of No. 283-A is cone 26-27. Further studies are needed before the possible uses of these clays can be predicted. 10. Low Strength. No. 16 (p.WS). Riverside County. Alberhill C. & C. Co. ''Select West Blue." See also No. 23 in class 5. This is a plastic, buff-burning clay that has a wide vitrification range above cone 7, and is used for face brick and pottery. It contains 22.6% of 4-200-mesh sand, high in ferro-magnesian minerals, which results in a pleasing granitic texture when fired above cone 7. The plasticity is fair, the dry strength is low, and the clav is soft and friable in tlie dry state. The colors are : drj^ 15'""f ; Avet, 15'""b ; cones 010 to 02, 17''f ; cones 1 to 5, 17'"f ; cones 7 to 13, 17""f, with a granitic texture. Finger-nail hardness is developed at cone 06, steel hardness at cone 02, and bloating begins at cone 13. The total maximum linear shrinkage, plastic basis, is 14.0%, at cone 11. The softening point is cone 18. The best firing range is from cone 02 to cone 11. No. 55 (p. 195). San Bernardino County.. 4.2 m. N.E. of Bryman. Gladding, McBean and Co. This is a vitrifying clay of value in face-brick manufacture. It has poor plasticity, low dry strength, and a soft, oi)en, dry condition. A large proportion of non-plastic matter is present which is high in iron, and results in a pleasing granitic texture when fired. The ])ercentage remaining on 20()-m('sh is 48.6. The colors are: dry, 7"f ; wet, 7"d ; cones 010 to 04. 7"f, cones 02 to 5, 9'"d ; cones 7 to 11*, 17""d; cone 13, 15""'(1. Finger-nail hardness is obtained below cone 010, and steel hardness develops at cone 1. Absori)tions below 10% are obtained at cone 3 oi- above, and bloating begins above cone 11. The maximum total linear shrinkage, plastic basis, is 9.5%, at cone 11. The softening point is cone 18. The best firing range is from cone 02 to cone 11. CLAY RESOURCES AND CERAMIC INDUSTRY 315 No. 8:i (p. 174). Riverside County. Albeiiiill. L. A. B. Co. "Clay Shale." This is a sandy, buff-burning: clay shale, with weak plasticity and incdiuin low streu^Hi. It effei-vcsccs sli<:li11y in liydroehloric acid. In the dried condition it is soft, medium-grained and open-textured. The colors are: dry, 17''d; wet, 17"; cones 010 to 3, 5'f ; cones 5 to 11, 5)'f; cone 13. 17'f. Troii sjjecks are numerous. Finger-nail hardness develops below cone 010. but steel hai-diiess is l)ar('ly attained at cone 13, at Avhicli point bloating begins. The fired structure is sound, granular, and open. The maximum total linear firing shrinkage, plastic basis, is 3.5%, at cone 11, nearly all of wiiich takes ])lace during drying. The softening i)oint i.s cone 23-20. The best firing range is from cone 010 to cone 11. The clay may be used with more i)lastic clays as an ingredient of face brick mixtures, if the mottled texture is not objectionable. No. 88. (Dei)osit not deseril)C(l.) Riverside County. Hudson Ranch, near Elsinore. Tliis is an imi)ure silica sand, mixed with enough clay to im])art weak plasticity to the mass. The dry strength is medium low, and in the dried condition it i.s coarse, open, and friable. The colors are: dry, 21""f ; wet, 17""f ; fired, from cone 010 to cone 11, grayish-white, with black specks above cone 7. Steel hardness is devel- oped at c(me 11. The fired structure is coarse-grained, and weak. Enough fluxes are present to cause fusion to begin at cone 9. The total linear shrinkage, plastic basis, at cone 9, is 8.3%. The material has little ceramic value. No. Ill (p. 178). Riverside County. Alberliiil. P. C. P. Co. "Lower Douglas." This is a pink-burning clay containing 28.6% of +200- mesh sand, but nevertheless i)()ssessing good jilasticity, and a medium low dry strength. The dried condition is soft, medium-grained, and open-textured. The colors are: drv, 17"f; wet, 15"d; cones 010 to 1, 9"f ; cone 3, 15" f ; cones 5 to 9, 13'"f ; cones 11 and 13, 17""f . Above cone 5. the clay is strongly mottled with iron specks, resulting in a pleasing fine-granitic texture. Finger-nail hardness appears below cone 010, and steel hardness at cone 1. The fired structure is sound and fine-granular. Slight bloating begins at cone 11. Absori)tions below 10% are obtained at cone 5 or above. The maximum total linear shrink- age, plastic basis, is 12.4%, at cone 9. The softejiing point is cone 19-20. The clay is useful in terra cotta, face brick, and faience tile bodies. No. 167 (p. ISA). Nevada County. Wolf. Coe property. Pine Hill :\rine. See also Xo. 159 and 160 in class 1, and 166 in class 11. This is similar to No. 160, but contains more iron. The plasticity is weak, the dry strength is low, and in the dried condition it is soft, fragile, fine- grained, and open-textured. The colors are: dry, 7"b ; wet, 9'b; cones 010 to 3, 7"b; cones 5 to 9, 7"d ; cones 11 and 13, 17"'d. Finger-nail liardness is developed at cone 010, and steel hardness at cone 11. Less than 10% absorption is obtained at cone 13. The fired structure is sound, and below cone 11, is fine-granulai". Above cone 11, it is stony. The total linear shrinkagf. ])laslic basis, at eone 13, is 13.6^1,. The sofi cuing [>oiut is cone 23. No. 170 (p. 136). Nevada County. Banner Mountain road. This is an impure, sandy, i)ink-])urning clay with weak plasticity, and medium- low dry strength. In the dried condition it is medium-hard, coarse- 316 DIVISION OF MINES AND MINING grained, and open-textured. The colors are: dry, 17"d ; wet, 17" b; cones 010 to 06, 13"b ; cones 04 to 1, 13"d. Steel hardnes.s is develoi)ed at cone 02. The fired structure is sound, granular, open-textured, and the surface texture is smootli. Tlie total linear shrinkage. ])lastic basis, is 4.8%, at cone 3. It could be used for common brick, but the plasticity is barel.y sufificient. No. 238 (p. 70). Calaveras County. Campo Seco. This is an nnpure sericite schist that is said to have been used as a refractory clay in the former smelter of the Penn Mining Co. The jilasticity is weak, the dry strength is low, and in the dried condition it is very soft and friable. The colors are : dry and wet, grayish white ; cone 010, 17"f ; cones 06 to 1, 17"d ; cones 5 and 9, 2V'"i. Steel hardness is developed at cone 02, and less than 10% absorption at cone 5. A vesicular structure developed at cone 9. The maximum total linear shrinkage, ])lastic basis, is 9.3%, at cone 5. The material is of doubtful value in ceramics. No. 269. Inyo County. American Silica Co. "Death Valley Super- fine." This is a very fine-grained, sandy material, with sufficient clay to give a short and s])ongy plasticity to the nuiss. There is con- siderable effervescence in hydrochloric acid. The dry strength is medium Ioav, and in the dried condition it is hard, and has a fine sandy texture. The colors are : dry, 17'"d ; wet, 17'"b ; cones 010 to 06, 15"f ; cones 04 to 1, whiter than 17"; cone 3, 17"d. Steel hardness is devel- oi)ed at cone 3. The fired structure is sound and fine-granular. The total linear shrinkage, plastic basis, is 26.6%, at cone 3. The softening point w^as not determined. No. 284 (p. 232). Tulare County. Ducor. W. A. Sears deposit. See also No. 285, class 5. and 283-A and B. class 9. This is an impure kaolin, having weak plasticity, low dry strength, and a medium-hard, coarse-grained, open texture in the dry condition. It was only fired to four cone numbers. The colors are: dry, 15"d; wet, 17"; cones 1, 5, 9 and 13, 15". The fired colors are rather unsatisfactory yellows for most ceramic jiroducts. The fired structure is weak and coarse-granu- lar. The total linear shrinkage, plastic basis, is 6.4%. The softening point was not determined. This is the least satisfactory of the sam- ples tested from this de])osit. Yellow scumming is jironounced. b. Dense-Burning, Less Than 6% Apparp:nt Porosity Below Cone 10. 11. Low Strength. No. 166 (p. rm. Nevada County. Wolf. Coe property. Pine Hill Mine. See also No. 159 and 160 in class 1 and 167 in class 10. This is similar to No. 159, but contains a higher jiroportion of fluxes and color- ing matter. The residue on 200-mesh is 4.6%. The plasticity is smooth, and moderately strong, the dry strength is medium-low, and in the dried condition it is medium-hard, fine-grained and close-textured. The colors are : dry, 13"f ; wet, 9"d ; cones 010 to 06, 7"f ; cones 04 to 3, 5"f ; cones 5 and 7, 5""f ; cone 9, ]3""f. Plasticity is not destroyed until cone 06 is reached, but steel hardness is developed at cone 02. Less than lO'^c absorption api)ears at cone 02, and a vesicular structure is developed above cone 3. The fired structure, from cone 02 to cone 3, CLAY RESOURCES AXD CERAMIC INDUSTRY 317 is soniu], and stony, with a smooth surface texture, total linear shriiii\a;^('. phistic basis, is l.l.S';, at eone '^. |)oiiit is cone 1:5. Tlie ehiy nii^dit Wud some use as a vit hurt', eream, or i)ink bodies burned between the limits eone 8. TABLE No. 22. M. Buff-Burning Clays. B. Non -refractory clay.s, .softening point cone 27- Tlie maximum The soften iiig rifyino ao-ent in of eone 02 and a. Open- l)nrning, not below 6'/f apparent porosity lielow cone 10. ;i. Medium to high strength. Soften- ('lav ing pt. No! Tc S.W. c/c P.W. . o >, c P c o O O, >. a c e*5 n o a> c 'a bl: a o. j:2 bC Z E o rt _c Ol V} UJ -1 OQ < OQ it: 3 s 3 o 1-J C3 is o 1- ffi >. o -a o •~^ ■ o ^ ?; c/j — u .^ OJ C3 Ol - m O O O ^•;; !!!!!! 1 1 1 1 !!! 1 ,^-^^ >■ ;;;;;;;;;;;;;; ; I '. I ! I ! 1 I 1 a; 5 O < O 00 =D ■— ' iC OO ■^ 1 1 05 'lOOO (>» CVKM^.— .— ' <« . 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OS o - (1h £5 S > 6§ CLAY RESOURCES AND CERAMIC INDUSTRY 319 Al)sorption and linear shrinkage curves for clays of class 9. i2 I I I I 010 C8 Ob Of OZ I 3 5 7 9 II n /^ A No 19 , 10 20 10 —' S ^ He 25 s . _s_ ^ -- — — -- ^ jA No 56 20 10 10 10 S .. .. ^ No 2A A. ^ -- s r" Ci — N ^ No 35 rJ s -- — > .-- -- ~ ^ 010 08 06 0^ OZ I 3 5 7 9 II 13 /T 5 2ot 10- /V£AT rREATnfN T IN C0/V^5: I I o 10- 10- T ' — — No 99 S ^» -- No II 4- ^ ^ — ^ — s .. ^ " * A No 13 5 — " ^ ^ ^ W S±i ss .5. ^^ •• " *v •= -7^ \ --1 ^_ No 16 & S ^ ~~ -^ _ No 169 A ir< J. ^^ — — N ^-— -- ..^ _ HEAT TREATHENT IN CONES. tt: U, i -J I I OlOqSOi, 0^ OZ I 3 5 7 S II 15 IS" 20 10 10 30 20 10 O £0 10 - A *^ *V, No 17 3 N, - ^ s. -. — _ _S -- •** ^ "* ■' No, 5 _s .* <] ■— ^ < ^ A No lb 3A ^ — ^ — - — _S — — — '' -- -- — " — - _A_ No 25 3B ^^ Jt* .S. .. .. ^^ ,^m — — — HEAT TREATnENT IN C0NE5. 320 DIVISIOX OF MINES AND MINING Absorption and linear shrinkage curves for clays of classes 10 and 11. 610 08 0b (H 02 I 3 5 7 S II 13 IS" I a; I -J I 20 10 20 10 20 10 20 10 ,A No 16 ■^ X 5 ^ -- — ^ "" " '■ >1 A No 55 >-. V. 5. ^' — ^ -- >i — "a" Nc 82. S k — A, - No 38 s — V S i \ tzz. ^^''M ^/T? '^ )^A fn fN Til vo om :S. •^ 010 08 Ob Of OZ I 3 5 7 9 II IJ isr «^ 20 Q» 5 1 10 0=^: tt: ^ 10 ^ 20 frS 10 V 5^ >. ^ v:; ?n ti ^ ^ 10 t-*! •^ *^ 1 A No II 1 -n "^ — s S_ .. _- >. e.^ < - a" ^"" ^^" ^ ^ No ■ — , 16 7 \ ^ s .. ^^ .- ,''\ A ^ No 17 S .. A No 23 8 ^ •- ■^ _S_ — — - =*i; ** AZVir TREf\Jt1£NT INC0NE5. 010 08 0b 0'^ OZ I 3 5 7 9 II 15 L lO ^ CO .so ^ Ct ^ ^0 2^ ^0 ■2: ft 20 (o (.o ^ m n or VI C ?0 <4 u- i^ 10 s t ih) n No 26 9 ■~~- <, ^ \ N \ > — — — -- ^ No 26 4 A ■^ ^ « »• _S_ -- -- — \, A No}l6 6 \ / ^ S_ ^'' — — f /ViVfr TREfimfNT IN CONES. (LAY RESOURCES AND CEUAMIC INDUSTRY 321 III. RED-BURNING CLAYS. A. Open- Burning, Do Not Attain Less Than 6% Apparent Porosity at Any Temperature Short of Actual Fusion. 12. ]\I{'(liuiii 1() 1 1 lull strength. ^'o. 8 (p. 163). Riverside County. Alberhill C. & C. Co. "Red Clay N'o. 2." This is used ]ii'iii(M]ially as a rcd-eolorinp- day in the nianu- facturc (if I'licc hi-ieiv and other higli-^'rade red-bnrnetl pi'oduets. It is siiiiilai' in its properties to No. 7 (class 13), but is not (juite as uniformly line-grained, has gi'eater sliiiidvage and strengtli, and vitrifies more tlioi-ongldy at eone 13. The eolors ai-e as follows: dry, 11"1); wet, 11"; cones 010 to 3, H'b; cone 5, !)"b ; cone 7, 7"b; cones 9 and 11, 5"; and eone 13, 5"'"b (flashed). Finger-nail liardne.ss is found at cone 08, and steel liardness at coiic !>. The total linear shrinkage, i)lastic basis, at eone 13, is 1.1.8^7 . Tlie softening i)oint is cone l!)-2(). The best firing range is from cone 08 to cone 11, and especially good results are obtained from cone 1 to cone 7. No. 18 (p. 1()3). Riversi(h' County. Alberhill C. & C. Co. "Clark Tuiiiiel ^Mottled." This is a i)lastic red-burning clay, used in sewer- pi l)e mixes to increase! the vitrification range of the mix. It contains 15.6/^ of -|-2()()-mesh .sand, has excell^init 'plasticity, medium dry strength, and in the dried state is medium hard and has a medium grain. The colors are: drj^ ll"b; wet, 9"; cones 010 to 06, 9'b; cones 04 to 02, n/; cones 1 to 7, 9'i; cones 9 to 11, 5". Finger-iuiil hardness is (levelo])ed at cone 010, and steel hardness at cone 3. The total linear shrinkage, plastic basis, is 17.8% at cone 11. The softening point is eone 19. The be.st firing range is from cone 1 to cone 11. No. 24 (]). 163,). Riverside County. Albei-hill C. & C. Co. "West Tunnel ^Mottled." This is a red-burning clay used in sagger mixes and face brick. It contains 13.8% of -|--00-mesh .sand and has smooth and .strong plasticit}', medium dry strength. In the dry condition it is medium-hard, fine-grained, close-textured, with a tendency to laminate. The colors are: dry, ll"d; wet, 9"; cones 010 to 04, 9'b; 'cones 02 to 3, 7"b ; cone 5, 9" ; cone 7, 5"k ; cone 9, 5"i ; cones 11 and 13, 1'". Finger- nail liardne.ss develops below cone 010, and steel hardness at cone 7. The specimens appear to be well vitrified at cones 11 and 13, but the absorptions are greater than 10%, at these temperatures. Some of the test pieces are slightly cracked. The maximum total linear shrinkage, plastic basis, is 14.2% at cone 11. The softening point is cone 18-19. The best firing range is from cone 5 to cone 11. Slight bloating is noted at cone 13. No. 26 (p. 163). Riverside County. Alberhill C. & C. Co. "West Yellow Stripping." This is used for face brick and sewer-pipe. It contains 21.8% of -4-200-mesh sand and has a smooth and strong plas- ticity, exceptionally high diy strength, high drying shrinkage, and medium firing-slirinkage. It laminates easily, warps badly in drying, and in the dry state is hard, with a fine grain and close texture. The colors are: dry, 19"; wet, 19"i; cone 010, ll"b, cones 08 and 06, 9"; cone 04, 11" ; cones 02 to 3, 7" ; cones 5 and 7, 5" ; cone 9, 7" ; cone 11, 5'"; cone 13, 5'"i. The fired colors are excellent for the darker shades -'1 — 54979 822 DIVISION OF MINES AND MININO of face brick. Piiifrer-uail liardiiess is present in the dry condition, and steel hardness appears at cone 1. Absorptions below 10/^ appear at cone 02. Bloatinff lieojins at cone i). The total maximum linear shrinka 7, and good structures are obtained from cone 3 to cone 7. No. 6.9 (]). 169). liiverside County. 10 m. south of Coi-ona. Emsco Clay Co. "Red Horse." This is a red-burning clay with smooth, strong plasticity. It is suitable as an ingredient of red earthenware, roofing tile, face brick, and sewer-pipe mixes. The sample contains I'-i.H'/r of -|-200-mesli sand. The dry strength is medium, and the dry condition is medium hard, fine-grained and close-textured. The colors are: dry, 9'b; wet, 9'i ; cones 010 to 04, 7'b ; cones 02 to 3, 9'; cone 5, 7''; cone 7 to 11, 5''i. The fired colors cover an interesting range of deep reds. Finger-nail hardness is developed below cone 010, and steel hardness at cone 04. Vitrification is practically complete at cone 7, but the apparent porosity is still above 8 per cent. All test pieces above cone 08 are slightly cracked. The fired condition is strong, tough and fine-grained. The total linear shrinkage, plastic basis, at cone 7, is 14.4%. The softening i)oint is cone 18-19. The best firing- range is from cone 04 to cone 7. [The shrinkage and apparent porosity data at cones 11 and 13 were lost. See absorption curve for general trend.] Xo. 73 (]). 169). Riverside County. Em.sco Clay Co. "Bone." Although this is locally" classed as a bone clay on account of its pisolitic structure in the raw state, it is lateritic, and contains so much iron as to give a low^ fusion point. It contains 46.8% of +200-mesh material. The iilasticity is spongy, ])ut fairly strong, the dry strength is medium, and the dry condition is granular, and o])en-textured. The colors are : dry, 9'd; wet, ll'i ; cones 010 to 04, ll'f ; cones 02 to 5, 7'^b ; cone 7 to 11, 9"'b ; cone 13, 5''''k. The fired colors are suitable for red face brick and roofing tile. Finger-nail hardness is develoi)ed below cone 010, and steel hardness at cone 1. All fired test pieces are sound, granular, and strong. Vitrification is complete at (approx.) cone 7, bej^ond which temperature, bloating gradually develops. The maximum total linear shrinkage, plastic basis, is 9.2^t, at cone 7. Absori)tions below 10% are obtained at cone 02 or higher. The softening point is cone 15. The best firing range is from cone 02 to cone 7. The clay can be used as a coloring agent, and to prolong the vitrification range of red-burned structural ware. Xo. 100 (p. 171). Riverside County. Alberhill. G., McB. & Co. "Yellow Striii])ing." This is an impure, sandy clay that is used in face-brick and sewer-pipe mixtures. It effervesces slightly in hydro- chloric acid. The plasticity is good, the dry strength is exceptionally 324 DIVISION OF MINES AND MINING high, and in the dried condition the clay has finger-nail hardness, and is dense and fine-grained. It contains 20.8% of 4-200-inesh sand. The colors are: dry, 15"d ; wet, 17''; cones 010 to 02, 9'b; cone 1, 9'i; cones 3 to 11, 5'i. Steel hardness is developed at cone 06. Absorptions below 10% are obtained from cone 02 to cone 9, inclusive. All fired test pieces are sound, and have a stony structure. Vitrification is complete at cone 5, and bloating begins above cone 9. The maximum total linear shrinkage, plastic basis, is 17.3%, at cone 5. The softening ])oint is cone 14-15. No. ion (p. 171). Riverside County. Alberhill. G., IMcB. & Co. "Sloan lied." This is a red-burning clay with good i)lasticity, medium dry strength, and in the dried condition it is soft, medium-grained, and open-textured. It contains 17.0% of -|-200-mesh sand. It is used for face brick, roofing tile, and .similar products. The colors are : dry, ll'd; wet, 9'k; cones 010 to 5, 9'b; cone 7, 7"b; cones 9 to 13, 5"i. Finger-nail hardness is developed at cone 06, and steel hardness at cone 1. The fired structures are all sound and stony, with a slightly roughened surface texture. Absorptions below 10% are obtained at cone 7 or above. The total linear shrinkage, plastic basis, at cone 13, is 15.0%. The softening point is cone 18-19. No. 112 (p. 178). Riverside County. Alberhill. P. C. P. Co. ' ' Hoist Pit Blue. ' ' This is a plastic, pink-burning clay that is used in sewer-pipe mixes. The plasticity is excellent, the dry strength is medium, and in the dried condition the clay is soft, medium-grained, and open-textured. It contains 25.0% of -|-200-mesh sand. The colors are : dry, 17'"b ; wet, 19''k ; cones 010 to 02, 7'd ; cones 1 to 7, 7''d ; cone 9, 9'''d ; cones 11 and 13, 13'"i. Finger-nail hardness appears below cone 010, and steel hardness at cone 1. Absorptions below 10% are obtained at cone 7. The fired structure is sound and heterogeneous, and the fired surface texture is smooth. The total linear shrinkage, plastic basis, at cone 13, is 16.1%. The softening point is cone 19. No. 113 (p. 176). Riverside County. Alberhill. P. C. P. Co. "Hoist Pit Red." This is a red-burning sandy clay of use in sewer- pipe mixes, roofing tile, red earthenware, etc. It contains 18.6% of -|-200-mesh sand. The plasticity is excellent, the dry strength is medium high, and in the dried condition the clay is hard, brittle, fine- grained and close-textured. The colors are : dry, 9'b ; wet, 7'i ; cones 010 to 7, 9'; cones 9 to 13, 9"'. Finger-nail hardness (nearly) is present in the dried state, and steel hardness appears at cone 3. The fired condition is sound and fine-grained, and the fired surface texture is slightly rough. The total linear shrinkage, plastic basis, at cone 13, is 11.3%. The softening point is cone 23-26. No. 117 (p. 131). Santa Cruz County. Castroville. Joe Area. This is an excessively plastic surface clay, that can almost be classed as an adobe. It is used for making hand-made roofing tile on a small scale. It has an exceptionally high dry strength, but must be dried carefully to prevent warping and ei-acking. In the dried condition it is dense, fine grained, and has finger-nail hardness. The colors are : dry, 17"'b ; wet, 17"'i ; cones 010 to 06, 9'b ; cone 04, 9' ; cone 02, 9"i. Steel hardness develops at cone 02. Bloating is well advanced at cone 1. All test pieces cracked on firing. The maximum total linear shrinkage, CLAY RESOURCES AND CERAMIC INDUSTRY 325 plastic basis, is 18.0%, at cone 02. Most of the shrinkage takes place iluring drying. The best firing range is from cone 010 to cone 02. The short vitrification range and the poor drying qualities of this clay preclude its general use for structural-clay products. No. 119 (y). 1^). Contra Costa County. Point Richmond. Richmond Pressed Brick Co. This is one of tlie tyi)ical red-burning Tertiary clays of the San Francisco Bay region that are widely used for the manufac- ture of common brick and buikling tile. As ground, the sample con- tains 43.2% of +200-mesh sand. The phisticity is good, the dry strength is medium, and the dried condition is hard, medium-grained, and open-textured. The colors are : dry, 17'^^' ; wet, 17""i ; cone 010, 13"b; cone 08, ll^'b; cones 06 and 04, 9''; cone 01, 7"i; cone 1, 5'k. Steel hardness is developed at cone 04-f-. Vitrification is complete at cone 1, and bloating begins at sliglitly higher temperatures. The fired .structure is sound and fine-granular, and slightly roughened surface textures are obtained. The maximum total linear shrinkage, plastic basis, is 12.1%, at cone 1. No. 155 (p. 151). Placer County. Lincoln. Gladding, McBean & Co. "Pit Sand." This is a red-burning sand-clay mixture that is used in tlie manufacture of roofing tile, sewer pipe, and other red-body ware. The residue on 200-mesh is 31.8%. The ])lasticity is fair, the dry strength is medium high, and in the dried condition it is hard, medium- grained, and open-textured. The colors are: dry, 17''"d ; wet, 17""; cones 010 to 06, 13"; cones 04 and 02, 1"; cones'l to 5, ll"i; cone 7, 5"m. Finger-nail hardness is present in the dried condition, and steel liardness is developed at cone 1. The fired structure is sound, except for light hair-cracks on the surface. The fired surface texture is rougli. Bloating begins at cone 7, before the body is vitrified to a low absorj)- tion. The maximum total linear shrinkage, plastic basis, is 15.0% , at cone 5. iVo. 77^ (p. 66). Butte County. Oroville. Quincy i-oad. This sample is representative of a residual deposit of decomposed granite. The plas- ticity is fair, the dry strength is medium high, and in the dried condition it is medium hard, coarse-grained, and open-textured. The colors are : dry, 15"d; wet, 15"; cone 010, 15"; cone 08, 13"; cones 06 and 04, 11'; cone 02, 9' ; cone 1, 7'i. These are good colors for common brick. Steel hardness is not developed up to cone 1. the upper temperature limit studied. The fired structure is .sound and granular, and the sur- face texture is moderately rough. The total linear shrinkage, plastic basis, is 8.2%, at cone 1. The material is suited for the manufacture of common brick. .Vo. i78 (p. 66). Butte County. Palermo. Lund Brick Yard. This is a clay-gravel mixture from a Tertiary river channel and is being used for the manufacture of common brick. Three separate samples were taken. No. 178-1, 2, and 3, each representing different phases of the material. Only one of these. No. 178-2, was tested completely. The others were fired to but three different temperatures each. The differ- ences between the three varieties are the result of differing proportions of sand, silt, and gravel. No. 178-1 contains 51.6% of +200-mesh sand, No. 178-2 contains 23.6%, and No. 178-3 contains 15.2%. This descrip- tion covers No. 178-2, and the reader is referred to the tabulated data 326 DIVISION OF MINES AND MINING for the results on the other samples. The plasticity is strong, but with a tendency to stickiness when excess water is used. Tlie dry strength is higli, and in the dried condition it has finyer-nail hardness, is medium- o-rained, and open-textured. The tendency to laminate is pronounced. The colors are : dry, ll'b ; wet, ll'i ; cones 010 to 3, 9'i ; cone 6, 5'k. Steel hardness is developed at cone 02, and less than 10/r absorption at cone 6. The fired structure is strong and stony,* with a slight tendency to crack. The surface texture is moderately rough. The total linear sliriid:lli is nuHliiuu low, and the dried condition is modiuiii liard, incdium frrained, and open-textured. The colors are: dry, 5"; wet, 'Vi; cones OK) to :{, 5"; cones 5 and 7, 9"'; cone 9, 9"i ; eone 11, ll"k. Steel liardness appears at cone 1. Less than 10% absori)tion is i)resent at cone f}. The fired structure is ^n-anular and hair-craeked. The total linear slirinkajje, plastic basis, at cone 11, is 17.5%. The softening point is cone 17-18. No. i:ri (]). 62). Amador roniily. lone. "Newman Red Mottled." This is a red-bnrniiifif clay witli «?ood ]>]asticity, low dry strength, and in the dried condition it is very soft, fine-gi-ained, and close-textured. It contains 'A:2% of -f'200-mesh sand. The colors are: dry, 9"b; wet, !)"; cones 010 to 02. 9')); cones 1 to 7, 9'; cones 9 to 13, 7'. Steel hardness appears at cone 1, and less than 10%j absorption at cone 11. The fired structure is stony, and at cones 11 and 13 several tension cracks appeared during firing. The total linear shrinkage, plastic basis, at eone 13, is 20.0%. The softening i)oint is eone 23-26. The best firing range is from eone 1 to cone 9. The clay can be used as a coloring clay for face brick, roofing tile, and similar ware. Xo. 171 (p. 136). Xeva(hi Connty. Xortli F.loomfield road. This is a i-ed-burning clay tliat could be used for common-brick manufacture. The plasticity is fair, the dry strength is medium low, and in the dried condition it is hard, fine-grained, and close textured. A tendency to develop drvinu- cracks was noted. Tlie colors are: dry, 17'f; wet, 21"'; cones 010 to 06, ir)"b; cone 04, 15"d; cone 02, 11'; cone 1, 9'. The fired colors are suitable for common brick, roofing tile, etc. Steel hardness appears at eone 02, and less than 10% absorption at cone 1. The fired structui'e is stony, and is sound except for a few small cracks, which may have been formed during drying. The surface texture is snu)oth. The total linear shrinkage, plastic basis, is 16.1%, at eone 1. Xon-plastics should be added. No. 1.98 (p. 125). Marin County. San Rafael. ' McNear Brick Co. Til is is a red-burning, sandy, clay-sliale that develops sufficient plas- ticity for brick and liollow-tile making. The dry strengtli is medium- low, and in tiie dried condition it is medium-hard, coarse-grained, and open-textured. Tlie sample as ground contains 55.8% of +2^^^-"i^^'' material. The colors are: dry, 15"b ; wet, 15"i ; cones 010 and 08, 7'b ; cones 06 and 04, 9'b; cones 02 to 6, 9"b. Steel hardness is developed at cone 1. The fired structure is coarse-granular and open, and hair- cracks are prominent, especially when fired above coiu' 1. The total linear shi'inkage, plastic basis, is 11.8%), at cone 6. The best firing range is from cone 04 to cone 6. The sample contains more non- plastic nuitter than the normal run-of-pit material. No. 218 {p. IHl). Riverside County. 8 m. south of Corona. This is a pink-mottled clay with excellent plasticity and medium-low dry strength. It is similar to No. 72 (Emsco Red). In the dried condition it is medium-hard, brittle, fine-grained and close-textured. The colors are : dry, ll'b ; wet, 9'i ; cones 010 to 3, 11' ; cone 5, 7'b. Steel hardness is developed at cone 3. The fired structure is sound and stony and the surface texture is smooth. The total linear shrinkage, plastic basis, is 19.5%, at cone 11. The softening point is cone 23. The clay is suitable for the manufaeture of face brick, roofing tile, and similar products. 330 DIVISION OF MINES AND MINING No. 256 (p. 52). Amador County. Tone. Core drill hole No. 60, Arroyo Seco Grant. This is a red-burning clay with good, but sticky, plasticity and medium-low dry strength. In the dried condition it is medium-hard, fine-grained, and open-textured. The colors are: dry, n"d ; Avet, 11" ; cone 1, 9" ; cone 5, 7"i ; cone 9, 9"' ; cone 13, 9'"i. Steel hardness is develo])ed at cone 5, and less tlian '[{Y/< absor])tion at cone 13. Tlie fired structure is weak and hair-cracked. The total linear shrinkage, plastic basis, at cone 13, is 20.3 /< . The softening point is cone 19-20. This is not a good clay, but could be used as part of a face-brick mixture. TABLE No. 24. III. Red-Burning Clays. A. Opeii-buniins, tlo not attain less than 6% apoarent porosity at any temperature short of actual fusion. 12. Medium to high strength. flay Soften- ing pt. No. % S.W. % P.W. % W.P. D.T.S. % D.V.S. t ri! o c ,-, c a l-l 3 m fO tm « 5f 00 < O -•i 1 1 1 1 1 1 I <; : ; : : i i i o 5 ^i — ■ .— CO ■ O cs -^ -d CM ' .— ic ' 00 r^ CO 00 ' ttJCsCl 11.7 12.0 28.2 24.4 9.6 "i6'2' eo CI .•» 10.1 26-2" m 6 12 2 1 1 CO CO »fl »C 00 ' o 1 '-^ o Ci o eo «■»»* • i^Cl- CO CO C-1 1 N lO c^iocioo "*r^ 01 M W ' " (M sO Ol '^ »0 ^O*O00t-* , , . .CO C *C 00 I 1 1 !oo — :coo 1 1 < ■ -*C0-^»O ! t^ COCC'^OO t-*co»o c: (M »C '17 ■ ■ ^ ^ ^' ^^ S ~ I*^ °^ ^ CI — — — C) — -7 1 — CI — 'M \ 1 ! I tc •-•ocsoo - . i 1 :o c- OC O =0 .— ■ eo Ci o: o t- oo :c . 1 1 1-^ »cooc^ •- . 1 1 1 ifio cocjcieo .^00 • 'cioo • 'CO ' > -i*'-*0300oO'*oo^cooo;--^*— CI P» ■ »d^ oo O CJ CO :D , 1-^ O — tC o: IM Tj< _|_!M ^ — r^ — 1 1 ! '0 0: COOOOO ■•** »c eo t^ , . . . . (M ^ eo ■^ 'OO OS ' ■ OS OS ' 5 O 20.2 35 5 34.8 18.3 16.3 17.0 15.2 23 3 22 I 19.5 14 6 2t.l 31.1 28.0 '7"0 25 6 HI) i\ O oo ' .»!- c; :C ic M ' ic -f ' W2CC b- . S (M CI ' Cfl -^ Cfl ■ lO-'fooco-^ cr. :r-0!;0'rf — — • 500000:00 -J< 00 MOOCO ^ CO , ^ — 1~ -v" --o ■^^oa^t^-^ '.tZlZ^ci?^ iioa::-— 0— tOOOCl-^OOOOOO iOJ — CICOO iCI-O':000t^t^C0 ' CI CI — w — oo-.rooo-^ — ■rtin — i^ — !M — ococJTco '■gSS'"!2:XJ?:3 .40 ■ ' '-S* 0000«3-^000 • • tci • ■ oi !£>co — oiim>*C ■ -^ 1 • "*?• coeo'^cocieoco . :o ' ' 'O t— eo 00 --I* 00 Tj> CO > t h- 1 -f CO "-r »c '-C ci ■**• i^ O o g^ c^u50Qoo-x)->o^-^~^--^a-^oooa: — ocoo : — — corooo ..J « a5 . .a: ^j- 00 =■- «; c 00 ■ ..p «>coi-i-ot-ooo-.o--cc^o CO ^ =c : -o oo i co - . rn 0: (M M =0 CO t- 00 ri 00 a: -J- "5 c-J M cd- :0 ;t- : t- CB C-) — oc — . . ;l- •* t~ 1 1 + ++ + ■ + or o o c jj ^, „ = ,-L-:c;~ju; = .o^iracOi.-5M-t-t- — "-oocMot- lot^d^t-tMcso-o-* ; ;«5 or- — loiococo . C0--C.M^ = «=0-C>OWOOC«C^OO lo-SCOCOCOCOO- ; ;0O 000«-.C-0 ; o o t- .n 00 o 17 - — — — -i- -^ = == "« >" — c^J - "»• '■'' CO o; oo c-i CO r- — co^c?S^?S?lSco?^t^icocococ-icocococo?^ .coc-lScoco — co • -eo ic c» 00 IC c; ' 'to i^O iC -f 00 CO ■ . . ^.^ 5*3 c^ ^ ^ ^ cv, CO > OOCMIO lOOOQOOSCOeoOO • loo -^COOOOCOOCi ■ ' 'i^ cJooo-^oo ! ; ; 1 +- +-^ : ^'1 aooo-^^Mico»cr:cooicc-icot — IMCO «-— ^-*-, ;y. — .»1-^— ;C"^ — t^. — ..-_ 1 — Cl^l^- — 0000 — Clas s No.. . C) CO Oh < CD > 332 DIVISION OF MINES AND MINING 010 Absorption and linear shrinkage curves for clays of class 12. 08 06 0^02 I 3 5 7 9 II 13 JS' 1/ ^ 20 1 ° ^ 20 % '^ *-^ _Aj Na 6 V — ^~ _S ^^ -- — — — — " " ^ _A. V^ No (6 ^ ^ • -- _» _S_ ■ — — — — — ■"■" % A No 24 ^ 20 »« 10 ^" % 1 - \ ~ — _S „ .- ~~ — - No 26 _A_ ^ _. _S -' — " rr ^ 1*. ^ ~ ~ ^* . . 01008 06 OfO Z / 3 S 7 9 1/ 15 /£■ //£AT TREAmfNT IN C0/iE5. HEAT TREATnENT IN CONES. 010 08 06 0^ OZ I 3 ^ 7 9 II 13 IS' I I -J I I i 20 He '^ — ^ A - _S ^^ — '- " =^ 5*, — ?o No 10 10 — -~ < / ^ „ Jl .- :^ ^ — •- / \ ?0 »- A No 10 s in *^ \ .^^ 20 in ,s ,' — — — •< -^ __ — _A, •\^ No II 2 > - s. s r^ — — — > - HEAT TREATMENT IN CONES. 52 -J I 010 08 06 0^ 01 I 3 5 7 9 II 13 IS' 20 10 10 10 10 20 10 A No 1 1 3 " "■" — — S _. _ ^ _ . — -- — _ A No II 7 .4 \ ■^ < _ No) II 9 S \ < ^ ■X ""^ ■^ ^ 15 5 s ,, « — -- — A : , S No 17 S s A£- ^ ,- 1 HEAT TREATHEN T IN CONES. CLAY RESOURCES AND CERAMIC INDUSTRY 333 Absorption anrl lin<-;tr shrinkago curvis for clays of class 12. 12 tt; I ■J 010 OB 06 Of Ol I 3 5 7 9 // 13 /S" CIO 08 06 Of OZ / 3 5 7 9 // 15 /S' I I I 20 10 20 iO ZO 10 ZO 10 No 17 8-1 — _A _S „ _ _ No 17 &-1 — ^ >>_ w S ^^ S < A No 17 9-3 ■""■ — $ — , ^ No 18 ^ ^ V. J. -'*' -' ^ HE/\T TREAineN T IN COfiES. «^ 10 >-. «2> ^ 10 I ^ ^ 10 1 » *« 10 •« ^' I C; to I ^ < No 182 s -• Z^ •"^N^ — — ^ \. /I No Id 3 s \ < Zl = A \ No I9|9 \ s ^ ^'' Nc ^ ^ ^ No 20|6 s ,^»- iTT" ■I* A 7 No 2( 4 ■"■ !r f < \ 1 -y^/jr TREAmENT IN C0IVE5. a: S I I 010 08 06 Of OZ I 3 5 7 9 II 15 IS' 10 10 10 JO o 30 ZO 10 "^ _A \ No 21 6 ' _s_ • <: ■*" < No 21 7 }' N ^ >^ No 22 1 _s — — — ^ """ No 25 1 ^ -K - A No 26 1 '>> \ s ■- — — s^ — **^ ^ HEhT TREAjnENT IN COfiES. 334 DIVISION OF MINES AND MINING i ft: S I I Alisiirptinn and linear shrinkage curves for clays of class ,„. ao 08 06 Of Ol I 3 5 7 9 II li IS- 010 08 0b Of OZ I Z S 7 9 // 13 /T 20: to- 20. 10 ZO- IC o 20- 10 ^__ _A No 7 — I ! — — ^ S .. ^ ^ r — — — F— "^ A Nc 72 ■- ^ "~" — s. S ^^ ___ — — — *' "^ y > Si. No 12 a N _- _. — — — _S_ " -- f^ — a" V No 13 1 -\ "~~ ^ N *- -< ^- _s_ ,, x ^ — — ~~ ** N ■ HEhT TREfiJnENT INCOMES. i2 Ci 10 5 ^£0 i 10 % "< ^ 20 »« 10 ^" I f^ 20 I ■-^ A V NollT 1 r— " \ S( ^ «• _S y Jt^ __ A_ No 19|8 ^ - — — _s — — -" •* =" A No 21 S — 5-^ ^'^ S ^.^ s^ .• — N A No 25 6 \ ^ _S — — -• ^"^ /y£>}7 TREATMENT INCOMES. Ill-B. Dense- Burning. Less Than 6% Apparent Porosity at Vitrification. a. With Loxo Vitrificatiox Raxge, \ Cones or Moke. 14. Mainly Medium to High Strength, But Also Including Some Clays of Low Strength. No. 10 (p. 163). Riverside County. AlberhiU C. & C. Co. "Hill Blue Green." Tliis is a fine-grained, exee.ssively-plastie clay that serves mainly as a strengthening clay in sewer-pipe and similar mixes. The dry strength is verv high, but the excessive dr^dng shrinkage causes serious warping and cracking when used alone. The dry clay is very hard and dense. The colors are: drv, 23"'"b; wet, 21'"'; cones 010 to 06, 9'b ; cones 04 to 1, 9" ; cones 3 to 5, 9"' ; cone 7. 1"' ; cone 9, l""b ; cone 11, 13""d (flashed). All test ]iieces cracked on firing, except those at cones 010 and 08. Finger-nail hardness is found in the dry state, steel hardness is developed at cone 04, vitrification is complete at cone 1, and bloating begins above cone 5. The total maximum linear shrink- age is 22.3'/ , at cones 3 to 5. The softening i)oint is cone 14-15. The long vitrification range and excellent dry strength of this clay are its princijial merits. No. 21 (p. 163). Riverside County. AlberhiU C. & C. Co. "Sagger Clay." This is a pink-burning, plastic clay that finds use as a vitrifying agent in sagger bodies. It has a smooth, strong ]ilasticity, and a medium low dry strength. There is slight effervescence in hydrochloric acid. In the dry state it is soft, with a medium-fine grain, and has a tendency to laminate. The colors are : drv, 7"b ; wet, 7" ; cones 010 to 04, 5'd ; cone 02, 7'd ; cones 1 to 5, 7"d ;" cone 7, 13"'d; cones 9 to 13, 17"'d. Iron specks are prominent at cone 7 or above. Finger-nail hardness is developed below cone 010, and steel hardness at cone 1. A few small CLAY RESOURCES AND CERAMIC INDUSTRY 335 (Tiii'lss appeared in the test iirin^i, jji-obably cau.sed by too rapid firing duriiiji- tlu' water-smokiiijr stajie. Tlie total linear .slirinkajre, plastic basis, at cone }'). is 2\.-\' i . The softening point is cone 2."?. The best firing i-ange is from eone 02 to cone ^'^. The wide vitrification range of this eiay within tlie limits of commercial firing is its principal merit. With the addition of non-plastic material, it is suitable for pink- and l)uft'-burned face brick, roofing tile, and similar ])roduets, as well as for saggei-s. A'o. ^^;? (p. 163). Riverside County. Alberhill C. & C. Co. "Yellow Owl Cut." This is a yellowish clay containing 12.6'/, of +2()()-mesli sai.J, and has good jjlasticity, high drying shriidcage, medium-high dry strength, and good dry condition, though with a tendency to laminate. It is used in sewer-])i])e mixes. The colors are : drv, 15"d ; wet, 15" ; cones 010 to 08, 5'd ; cones 06 to 0-1, 7'd ; cones 02 and 1, 9'b ; cones 3 to 7, 7"b ; cones 9 to 13, 9""d. Finger-nail hardness is developed at cone 010, and steel hardness at cone 1. The total linear shrinkage, plastic basis, is 1H.6'(, at cone 11, and slight bloating a])i)ears at cone 13. The soften- ing i)oint is cone 17. The best firing i-ange is from cone 02 to cone 11. The most desirable features of this clay are its dry strength and wide vitrification range. Xo. 75 (p. 174). Riverside County. Alberhill. L. A. B. Co. "Red Xo. 2." This is a vitrifying clay with its light-red firing colors that is valuable in roofing-tile and face-brick mixtures. In the natural state it is hard and brittle and the color is mottled i)iidv and cream. It con- tains 16.4'>v of -(-200-mesh sand. The plasticity is excellent, the dry strength is medium, and the dried condition is medium-hard, and medium close-grained. The colors are: drv, 7"b ; wet, 7"; cones 010 to 1, 9'b; cones 3 to 9, 9"b ; cones 11 and 13, l""i (flashed). Finger- nail hardness ai)pears below cone 010, and steel hardness at eone 3. Absor])tions below lO'^ are obtained at cone 5, and vitrification is com- l^lete at coiu^ 11. Slight bloating ap])ears at cone 13, under reducing conditions. The fired test pieces are moderately hair-cracked, and at cones 11 and 13 a few large open cracks appear. The maximum total linear firing shrinkage, ])lastic basis, is 24.0^^, at cone 11. The soften- ing point is cone 20-2)]. The best firing range is from cone 3 to cone 11. The clay should be mixed with non-plastics to obtain safe firing l)roperties. No. 123 (p. 56). Amador County. lone (Carbondale). Lea.sed by G. A. Starkweather. "Yaru No. 2." This is a red-burning clay with smooth and weak ])]asticity. and medium dry strength. It contains 5.4% of -|-200-mesh quartz-mica sand. In the dried condition it is soft, fine- grained and close-textured. The colors are: dry, 17"d ; wet, 17"b; cones 010 to 7, 9' ; cone 9, 9"" ; cones 11 and 13, T''\ Steel hardness is developed at cone 02. Less than 10% absoi'])tion a])pears at cone 1. The fired structure is sound, and the texture is smootli. Vitrification is complete at cone 11, and blistering a])i)ears at cone 13. The maximum total shrinkage. ])lastic basis, is 22.1%, at cone 11. The softening j)oint is cone 27-28. The best firing range is from cone 1 to cone 11. The clay may be used for face brick, roofing tile, red-burned pottery, etc. No. 127 (p. 57). Amador County. lone. M. J. Bacon. "Bacon Red." This is a red-burning clay with excellent smooth plasticity, 336 DIVISION OP MINES AND MINING and medium low dry strenutli. In tlio dried condition it is soft, and fine-grained. The colors are: dry, 7"b; wet, 7"; cones 010 to 5, 9'b; cone 7, 7'b ; cones 9 to 11], 7"b. Steel hardness appears at cone 1. Less than 10% absorption is obtained at cone 7. The fired structure is sound, and the fired surface is smooth. Tlie total lineai- shrinkage, plastic basis, at cone 13, is 20.0%. The softening point is cone 27. The best firing range is above cone 1. The clay may be used for face brick and roofing tile, and for pink colored pottery or tile bodies. Xo. 148 (p. 156). Placer County. Lincoln. Lincoln Clay Products Co. "No. 8." This is a red burning variety that possesses nearly the same plastic, drying and firing i)roi)erties as No. 146, in class 8, but with a lower softening ])oint. It contains \2.V/v of -|-200-mesh sand. It is used for face brick, sewer pil)e, roofing tile, etc. The colors are: dry, 15'b ; wet, 15'b ; cones 010 to 04, f/d ; cones 02 to 3, 7"b ; cone 5, 7" ; cone 7, 7"; cone 9, l'"i; cones 11 and 13, V". Steel hardness develops at^cone 1. Less than lO^^ absor|)tion is developed at cone 3. The fired structure is sound and stony. Blistei'ing is noticeable at cone 11. The maximum total linear shrinkage, plastic basis, is 20. 29^, at cone 9. The softening i)oint is cone 20. The best firing range is from cone 1 to cone 9. No. 177 (j). 66). Butte County. Oroville. Quiney road. This sam- ple contains a high i)roi>ortion of partly-deeom])osed volcanic ash. Since it is the only sami)le of its type on which test data could be secured, the results are given as a matter of general interest. The plasticity is weak and spongy, the dry strength is medium-high, and in the dried condition it is hard, fine-gi-ained, and close-textured. The colors are : dry, 17"'f ; wet, 17"i ; cones 010 and 08, 15"d ; cone 06, 13'b ; cone 04, 13'd ; cones 02 and 1, 17''i. Steel hardness is developed at cone 04. The sharp change from 16.8% porosity at cone 04 to 0.1% porosity at cone 02 should be especially noted, together with the corresponding sharp decrease in volume. The fired structure at cone 02 is glassy, and large cracks are present. Bloating and fusion follow when fired above cone 1. The total linear shrinkage, i)lastic basis, is 26.6%, at cone 1. No. 181 (p. 80). Humboldt County. Angel Ranch. This clay has been used by Mr. R. H. Jenkins at the Humboldt State Teachers College, as a casting clay for pottery. It has good ]ilasticity, with a tendency to stickiness. The residue on 200-mesh is 8.8'/* . The dry strengtli is medium high, and in the dried condition it is medium hard, fine-grained, and close-textured. The colors are: drv, 17'"f; wet, 17"'b ; cone 010, ll'f; cone 08, ll'd ; cones 06 and 04, 9"'d ; cone 02, ll'd; cone 1, 9"i; cone 3, ll"i; cone 5, 15". Steel hardness appears at cone 08, and less than 10% absorption at cone 04. Vitrification is complete at cone 1, and a vesicular structure is developed beyond cone 1. The fired struc- ture is sound and stony, and the surface texture is smooth. The maxi- mum total linear shrinkage, plastic basis, is 14.0%, at cone 1. The best firing range is from cone 08 to cone 1. No. 188 (p. 92). Lake County. Kelseyville. This is a red-burning thin-bedded clay shale. The clay slakes readil\' in water, and works into a smooth and moderately strong plasticity. It effervesces slightly in hydrochloric acid. The thy strength is medium, and in the dried CLAY RESOURCES AND CERAMIC INDUSTRY 337 eoiitlitioii it is iiiodiuin Jiard, fine-fjraiiied, and close-textiirtMl. The colors are: dry, 17'"f; wet. 17"'i ; oonc 010. 11"; eono OS, 13"; cones 06 lo 02, })'; cones 1 and 3, 7"k. Steel liardness is developed at cone 04, and less than 10' r absorption at cone 1. The fii-ed strength is medium and a few small cracks are present in all fired test pieces. The total linear shrinkage, plastic basis, is 25A% at cone 3. On account of excessive shrinkage, sliort vitrilication range, and medium strength, this material is only useful for manufacturing a poor quality of common brick, even if mixed witli non-plastic material. No. 202 (p. 68). Calaveras County. Valley Sjirings. California I'ottery Co. ''Pink ^Mottled." This is a fine-grained, red-burning clay, with smooth and strong plasticity, and medium dry strength. It con- tains AA'/v of -|-200-mesli santl. In the di"ied condition it is soft, fine- grained, and clo.se-textured. A strong tendency to laminate was noted. Tlie colors are: dry, 11'; wet, 7'i ; cones 010 to 04, 9"b; cones 02 to 5, 11" ; cones 7 and 9, 9". Steel hardness is developed at cone 02, and less than 10% absorption at cone 1. The fired structure is sound, tough, and stony. The surface texture is smooth. The maximum total linear shrinkage, plastic basis, is 20.6%, at cone 11, and bloating is apparent at cone 13. The .softening point is cone 20. This is an excel- lent face brick and roofing tile clay. No. 203 (p. 68). Calaveras County. Valley Springs. California Pottery Co. "Yellow Plastic." This is similar in its ceramic prop- ci-ties to Xo. 202, but is not so fine-grained, and contains more non- plastic matter. The residue on 200-mesh is 10.2%. The colors are: dry, ir)"b; wet, 15"b; cones 010 to 04, ll'b; cone 02, 9'; cones 1 to o, 11"; cone 7, 7"; cone 9, 5". Steel hardness is developed at cone 1, and less than 10% absorption at cone 5. The surface texture is rougher than that of No. 202. The total linear shrinkage, plastic basis, is 18.0%, at cone 13. The softening point is cone 19-20. No. 210 and 212 (j). 186). Sacramento County. Xatoma. Xo. 210 is a sample of ''Xatoma Xo. 1," and Xo. 212 is a sample of "Xatoma No. 3." They differ onl}' in the proportion of non-plastic matter, which is greater in X"o. 212 than in X'^o. 210. The clay is extremely fine- grained, and contains a high i)roportion of mica. The jilasticity is strong, and in the dried condition the samples have finger-nail hardness, are fine-grained, and close-textured. The clay must be dried carefully to avoid cracking. The dry strength of Xo. 210 is high, and of Xo. 212 is medium liigh. The colors of Xo. 210 are: dry, 13"b; wet, 13"i; cones 010 to 04, 9'; cone 02, 9'i; cones 1 and 3, 9k; cone 5, 9'm. The colors of X^^o. 212 are: dry, 13''; wet, 11"; cones 010 to 06, 13" ; cone 04, 7" ; cones 02 to 3, 7"i ; cone 6, 5"m. Steel hard- ness and less than 10% absorption are developed at cone 04, and vitrifi- cation is complete at cone 5. A vesicular structure appears at cones 7 to 9. The fired structure is sound and strong and the .surface texture is smooth. The total linear shrinkage, plastic basis, of No. 210 is 19.1%, at cone 5, and of X'^o. 212 is 16.9%, at cone 6. Mr. L. W. Austin, of the company, kindly gave the following data on Xo. 210 : 22—54979 Equivalent Acciinnil Si/.v in imn. mesh on 0.02 1.000 0.40 0.01 2,000 2. OS O.OOU 3,000 7.0G (1.(104 4,000 13.36 o.oo:! 5,000 20.19 0.002 10,000 29.89 0.001 20,000 52.07 0.000(1 30,000 59.22 338 DTVTRTON OF MINES AND MINTNfi Sizing Test of Natoma Clay No. 1. {{\\v Percent through 99.60 97.97 92.94 86.64 79.81 70.11 47.93 40.78 ]\ri'. Austin ro])orts the results of commercial firiiio' tests on Natoma No. 1 (our number 210) as follows: Drying shrinkage, 7.5 to 9.0%; total linear firing shrinkage at cone 5, approximately 15% ; absorption at cones 5 to 7, 0.35 to 0.1% ; bloating usually begins at cone 9. Another firing test gave a total linear shrinkage, plastic basis, of 20. 5^^, after heating to cone 5 in 36 hours and holding the finishing temperature for 4 hours. A number of clay products manufacturers have tested this clay, and some have introduced it into their mixes. It is particularly valuable for the purpose of producing a hard, strong vitrified body, with rich- red colors, and a smooth texture. In some plants the sviccessful use of this clay will require a modification of the drying procedure. The clay can be cast, or pressed, and takes die impressions very perfectly. In an auger machine, the finely divided mica is an aid to lubrication, yet the flakes are not so large as to cause excessive lamination. b. With Short Vitrification Range, Less Than 4 Cones. 15. Medium to High Strength. No. 1 (p. 218). Santa Barbara County. R. Muengenberg and E. 11. Whitiker. West Montecito Street, Santa Barbara. This is a mixture of a yellowish sandy clay and a plastic black adobe, mined locally and used for structural wares. It effervesces .slightly in hydrochloric acid. It develops a sticky plasticity and has high dry strength and good dry structure. The percentage of -f--^^0-i^i<^^li sand is 33.2. The dry color is 17"", the Avet color is 17""i, and the fired color to cone 3 is 9'i, a good color for common brick. Steel hardness is developed at cone 1, and bloating appears at cone 5. The maximum total linear shrinkage, plastic basis, is 12.8% at cone 3. The best firing range is from cone 02 to cone 3. No. 2 (p. 218). Santa Barbara County. Toro Canyon, near ]\Ionte- cito. An adobe clay, used in the Toro Canyon brickyard operated by jMuengenberg and Whitiker for the manufacture of red structural wares. The percentage of -|-200-mesh sand is 33.4. It develops a sticky plasticity and high dry strength with good (\vx structure. The dry color is 13"' and the wet color is 13'"i. The fired color is 9'i from cones 010 to 02, and 7"i from cones 1 to 3, both of which are good common brick colors. Steel hardness is developed at cone 1, and bloating appears at cone 5. The maximum total linear shrinkage, plastic basis, is 12.5% at cone 3. The best firing range is between cones 02 and 3. No. 4 (p 234). Ventura County. A yellow plastic clay from the Fer- nando (Pliocene) formation, north of Ventura, and used by the People's CLAY RESOURCES AXD CERAMIC INDUSTRY 339 LuiiilxT Co. for tlio mamit'aeture of ml si i-iirliii;il ware. It is finc- ^raiii(>(l. and 2.(i', of -]-200-mesh sand. It is used for common brick, but is suitable also for making liollow building tile. The plastic and drj^ing properties are such that it can be used alone. It has a higli dry strength, and in the dry state it is hard, with a medium grain and open texture. The colors are: dry, 17'"b; wet, 13'"i ; cones 010 to 02, 9'i ; cones 1 and 3, 7" ; cone 5, 9''i. These are nearly the same as in sample No. 30, and cover a good range of common brick colors. Finger-nail hardness is present in the dry state, and steel hai'dness appears at cone 1. Vitrification is complete at cone 3, and l)loating appears at cone 5. The maximum total linear shrinkage is 10.4% at cone 3. The best firing range is from cone 010 to cone 3, and Avell vitrified products are obtained from cone 1 to cone 3. No. 42 (p. 181). San Bernardino County. Vidal. "Blue." See also No. 43. This is a bluish, extremely fine-grained clay-shale of the ben- tonitic type. In water, it slakes readily to a smooth slip. It effervesces strongly in hydrochloric acid. When mixed with 57.7% water, it devel- ops a smooth, workable plasticity, without excessive stickiness. The drying shrinkage is high, and ordinary air-drying methods caused large drying cracks and excessive warping to develop. In the dried state, it is hard, fine-grained, brittle and close-textured. The dry strength could not be determined accurately. With the firing schedule emplo.yed, the clay was badly shattered, but data were obtained for cone 010 and cone 08. The colors are: dry, 17"'f; wet, 21'"d; cones 010 and 08, 15"b. Finger-nail hardness appears in the dry state, and steel hardness at cone 010. In view of the isolation of the deposit, it has no commercial A'alue. The fineness of grain, plastic strength, and apparently high dry strength are interesting features. No tabulated data or charts of firing shrinkage and absorption are presented. i\^o. 45 (p. 181). San Bernardino County. Vidal. "Pink." This clay is similar to No. 42, except that it contains more iron and more non-plastic matter, resulting in deeper fired colors, and lower drying and firing shrinkage. It effervesces strongly in hydrochloric acid. The dry strength is high. The colors are: dry, ll'f ; wet, 17""d; cones 010 to 1, 11"; cone 3, 13"k. Efflorescence is especially pronounced. Finger-nail hardness is present in the dried state, and steel hardness is developed at cone OS. At cone 3, kiln-marking and bloating begins. The maximum total linear shrinkage, plastic basis, is 20.0%, at cone 1. The fired structure is tough and strong. The best firing range is from cone 08 to cone 1. No. 60 (]). 100). Los Angeles County. Los Angeles. Davidson Brick Co. This is a red-burning clay suitable for the manufacture of com- mon structural ware. The ratio of clay to sand is such that the plas- ticity, drying and firing properties are entirely satisfactory without admixture with other materials. It contains 5.4%, of +200-mesh sand. There is slight effervescence in hydrochloric acid. The dry strength is medium-high, and the dry structure is hard, fine-grained, and open- textured, with a tendency to laminate. The colors are : Avy, 17"d ; wet, CLAY RESOURCES AND CERAMIC INDUSTRY 341 ]7'"i • cone 010 9'(1 ; cone 08, ll'b ; cone OG, U'b ; cone 04, 9"b ; cone 02, !"• cone 1, 9"'; cone 3, 5'"i ; and cone 5 (bloated) 9"'k. This affords an 'excellent range for red brick. Finger-nail hardness is obtained below cone 010, and steel hardness develops at cone 1. Vitrification is complete at cone 3. and bloating begins just below cone 5. All fired test pieces were sound and strong. Tiie maximiiin total linear shrink- age, plastic basis, is I6.97; , at cone 3. Tlie best firing range is from cone 010 to cone 3, or if vitrified products are desired, from cone 1 to cone 3. Xo. 61 (p. 102). Los Angeles County. Santa :Monica. (Jladding, McBean and Co. This is representative of tlie clay used, by several other plants in the same locality, and in some of the sewer-pipe and conduit plants in the Los Angeles district. It is a red-burning clay, witli suitable plastic, drying, and firing properties to permit its use as the sole ingredient of common brick, hollow building tile, roofing tile, etc., and as a vitrifving and bonding clay in sewer-pipe and elec- trical conduit mixes. It contains 18.07o of -f 200-mesh sand. The dry .strength is medium liiu'h. and the dry condition is hard, fine-grained, and close-textured. Tlie colors are: dry, 17"'; wet 13''"k; cone 010, ll'b: cone 08, 11' ; cones 06 and 04, 9' ; cone 02, 9'i; and cones 1 and 3, 9"k. These colors give a suitable range for the uses indicated above. Finger-nail hardness is obtained below cone 010. and steel hardness at cone 02. Vitrification is complete at cone 1, and bloating begins at cone 3. The fired structure is sound and strong. The maximum total linear shrinkage, plastic basis, is 13.1 7r, at cone 1. The best firing range is from cone 010 to cone 1, or if vitrified products are desired, from cone 02 to cone 3. .V^;. 89. Riverside County. Elsinore. Hudson Ranch clay. This is a red-burning sandy clay from an undeveloi:)ed deposit. It effervesces slightly in hydrocliloric acid. It has good plasticity, medium-high dry strength, and the dried condition is hard, medium fine-grained, and close-'textured. The colors are: dry, 17""b; wet, 17""; cones 010 to 06, 15"b; cones 04 to 1, 13"b ; cones 3 and 5, 7''; cones 7 to 13, 7"k. Finger-nail hardness is present in the dried state, and steel hardness is developed at cone 7. Ab.sorptions under lO^r are obtained at cone 11, and bloating is well developed at cone 13. All fired test pieces are sound. The maximum total linear shrinkage, plastic basis, is 20.2% at cone 11. The clay might have local use as a coloring and bonding clay, but its high shrinkage and short vitrification range are undesirable features. No. 118 (p. 192). San Benito County. Paicines. This is a yelloAvish, plastic surface clay, with a smooth, strong ])lasticity and exceptionally high dry strength! There is slight effervescence in hydrochloric acid. Tn^the dried condition it is hard, fine grained, and close textured. It contains 4.0^; of -l-200-mesh sand. The colors are: dry, 21""d ; wet, 21""; cone 010, 9'd : coups OS and 06, 9'b; cone 04, 9'; cones 02 and 1, 9'k; cone 3, 7"k. Finger-nail hardness is develoi^ed below cone 010, and steel hardness at cone 04. Less than 10% absorption is developed at cone 04, and vitrification is complete at cone 02, above which temper- ature bloating begins. The fired structure, up to cone 02, is sound and stony. The maximum total linear shrinkage, plastic basis, is 18.8%, at 342 DIVISION OF MINES AND MINING cone 02. This clay is not in use, but would be entirely suitable for red- burned structural ware, and is worthy of investigation as a casting clay. No. 172 (}). 136). Nevada County. ]\Ianzanita ]Mine, near Nevada City. This is the so-called "pipe clay" of the hydraulic mines. It develops fair plasticity, medium-high dry strength, and a medium-hard, fine-grained and open-textured dried condition. The colors are: dry, grayish white; wet, 28'""d; cones 010 to 04, 15"b; cones 02 to 3, ll"b; cone 5, 5"i ; cone 7, 5"k. Steel hardness is developed at cone 04, and less than 10*^^ absorption at cone 02. The fired structure is sound and stony, and the surface texture is slightly rough. Tlie nuiximum total linear slirinkage, plastic basis, is 24.8% at cone 5. Bloating is apparent at cone 7. The clay could be mixed with non-plastics and used locally for the manufacture of common brick. No. 184 (p. 80). Humboldt County. Eureka. Freshwater Slough. This is a common clay with good plasticity, and medium high dry strength. In the dried condition it has finger-nail hardness, is fine- grained, and close textured. The colors are: drv, 17""b; wet, 17""i ; cones 010 to 06, 13'b ; cones 04 and 02. ll'b; cone 1, 13'k. Steel hard- ness is developed at cone 04, and less than 10' { absorption at cone 02. Vitrification is complete at cone 1. The fired structure is sound, and the surface texture is smooth. The maximum total linear shrinkage, plastic basis, is 22.8% , at cone 1. The clay is entirely suitable for the manufacture of common brick, hollow tile, and roofing tile, but should be mixed with non-plastic material to decrease the shrinkage. .Vo. i(95 (p. 80). Humboldt County. Eureka. Loofbourrow Ranch. This is a common clay with sticky plasticity, and medium-high dry strength. It is extremely fine-grained and contains carbonaceous matter. In the dried condition it has finsier-nail hardness. The colors are; dry, 15'""b ; wet, 15'""i; cones 010 to 04, ll"b; cone 02, .5"; cone 1, 7"m. Steel hardness and less than 10% absorption are devel- oped at cone 02, and vitrification is complete at cone 1. The fired structure is sound. The total linear .shrinkage, plastic basis, is 19.3%, at cone 1. No. 200 (p. 73). Contra Co.sta County. Walnut Creek (Oxley siding). N. Clark & Sons. This is a red-burning, calcareous shale that is used as a non-plastic ingredient in sewer-pipe mixtures. The plasticity is weak, the dry strength is medium, and in the dried condi- tion it is medium hard, fine-grained, and open-textured. The colors are: dry, 17"'f; wet, 17"'b; cones 010 and 08, 15"b ; cone 06, 11'; cones 04 and 02, 9'; cone 1, 9'k; cones 3 and 5, ll'ni. Steel hardness and less than 10"^; absorjition are developed at cone 1. The fired structure is fine-granular, and the surface texture is slightly rough. Above cone 1, the test pieces are disrupted by one or more large cracks, and the greenish-broAvn coloration due to the presence of lime is a])parent. Tlie maximum total linear shrinkage, ])la.stic basis, is 19.7%, at cone 3. No. 211 ()). 81). lliiiiil)()ldt Comity. Near Strong's Station, Van Duzen River. This is a common-l)rick clay tliat has good pla.sticity, medium-high dry strength, and in tlie dried condition has finger-nail hardness, is fine-grained, and close-textured. The colors are : dry. t'LAY RESOUKCES AXD t'EHA.MR' INDUSTRY 343 21""d; wet, 21""b; cones 010 and 08, 13"b; cones 06 to 02, 11"; cones 1 and 3, 5"". Steel liardncss and less Hum lO'r absorj^tion a|>]iear at cone 1. The fired strncture is sound and stronj>', and the surl'ace texture is slig:htly roufrli. The total linear shrinkage, plastic basis, is 15.1%, at cone 3. The material could be successfully used for the manufacture of common bi-iek and hollow tile, although the fired colors are not especially atti'active. No. 223 (p. 141). Oranue ("ounly. ({oat Ranch. (J., McP.. tk Co. Red-burning -shale. Tliis material develops good plasticity if ])roi)erly ground and jiugged. The dry strength is medium-high, and in tlie dried condition it lias finger-nail li;ii-dness, and is close-textured. Tlu're is sliglit effervescence in livdrocldoric acid. The colors are: dry, ir/'d; wet, 17"k; cones 010 to 06, 13"b; cones 04 and 02, 11"; cone 1, o"\; cone 3, 5"k ; and cone 7. y'm. Steel liardness and less than 10% absor])tion are developed at cone 1, and bloating a])i)ears at cone 5. Tlie fired structure is sound and strong. Tlie maximum total linear slirinkage, plastic basis, is lA.b'/c, at cone 3. This is an excellent material for the manufacture of vitrified heavy clay products, such as sewer pipe, electrical coiuluit, paving- brick, and similar ware. No.264{]).A2). Alameda County. Decoto. M & S Tile Co. This is a common alluvial clay that is used for making hand-made roofing tile. The plasticity is good, the dry strength is high, and in the dried condition it has finger-nail hardness, is fine-grained, and close-textured. The colors are: dry, 17"i ; wet, 15"k ; cones 010 and 08, 11'; cones 06 and 04, 9'i ; cone 02, 7'k. Steel hardness and less than 10'/ absori)tion are developed at cone 02. Bloating begins above cone 1. The fired structure is sound, and the surface texture is smooth. The total linear shrinkage, plastic basis, is 14.27' , at cone 02. This clay belongs to the same geologic formation as No. 265, and its ceramic pro])erties are closely similar. No. 265 (p. 40). Alameda County. Niles. W. S. Dickey Clay Manu- facturing Comi)any, Plant No. 18. This is a common alluvial clay that is used for manufacturing hollow tile and paving brick. The i)lasticity is fair, but it is usually necessary to add from 15 to 20^ of a ])lastic clay from Lincoln or lone to secure suitable working i)roperties for an auger machine. The dry strength is medium high, and in the dried condition it is hard, fine-grained, and close-textured. The colors are: dry, 15"i ; wet, 13"k; cones 010 and 08, IT ; cones 06 and 04, 9'i; cones 02 and 1, 9'm. Steel hardness and less than lO^' absorption are develojied at cone 02, and vitrification is complete at cone 1. The fired structure is sound and strong. The total linear shrinkage, plastic basis, is 14.0%, at cone 1. 344 DIVISION OF MINES AND MINING TABLE No. 26. III. Red-Burning Clays. B. Dense-burning-. Less than 6% apparent porosity ;it \itrificatiun. a. With long vitrififation i-ange, 4 cones or more. 14. Mainly medium to high strength, but also including some clays of low strength. Soften- Clay ing pt. No. % S.W. % P.W. % W.P. D.T.S. % D.V.S. % D.L.S. In cones 10 3G.0 10.5 46.5 1530-1- 73.4 20.0 14-15 21 13.5 21.7 35.2 187' 23.3 7.2 23 22 23.5 14.8 38.3 525 45.0 13.0 17 75 16.6 21.7 38.3 292 28.7 8.7 20-23 123 19.2 23.2 42.4 228 31.0 9.4 27-28 127 16.9 20.7 37.6 121 28.8 8.7 27 148 15.9 19.3 35.2 255 28.1 8.6 20 177 22.1 39.7 61.8 582 26.4 8.1 181 14.2 12.3 26.5 794 28.6 8.6 188 25.1 31.7 56.8 364 36.2 10.8 202 17.5 21.5 39.0 230 29.4 8.9 20 203 15.3 18.6 33.9 232 27.1 8.2 19-20 210 21.5 15.5 37.0 1009 40.3 12.0 212 18.9 16.3 35.2 625 35.0 10.5 h. With short vitrification range, less tlian 4 coni's. 15. Medium to liig-h strength. Soften- (May ing pt. No. % S.W % PW. % W.P. D.T.S. (A D.V.S. % D.L.S. in cones 1 14.0 13.1 27.1 848 27.8 8.5 2 12.0 11.9 23.9 845 24.4 7.6 4 29.4 17.8 47.2 1212 54.0 15.5 5 22.1 18.3 40.4 ]0;!4 39.7 11.8 6 22.2 13.7 35.9 1258 43.5 12.8 30 15.3 19.5 34.8 595 27.3 8.0 31 6.4 13.5 19.9 903 12.5 4.0 43 30.4 16.7 42.7 1158 59.4 16.8 60 14.2 18.7 32.9 720 25.1 7.8 61 11.4 14.2 25.6 639 22.0 6.9 89 27.5 13.9 41.4 597 52.4 15.0 118 26.4 13.1 39.5 1363 53.2 15.3 172 16.6 41.0 57.6 352 20.0 6.3 184 26.4 20.9 47.3 703 43.8 12.9 185 18.7 21.4 40.1 502 31.2 9.4 200 14.7 2 8. 3 43.0 363 21.8 6.9 211 14.2 16.5 30.7 619 26.1 S.O 223 10.2 16.8 27.0 412 18.5 5.8 264 15.6 10.8 26.4 1020 31.8 9.6 265 12.5 Per 12.4 cent shrill 24.9 kage water. 791 25.2 7.8 % S.W. % P.W i^ Per cent pore water. W.P == Per cent water of plasticity D.T.S. =r Dry transverse Stl ength, pounds per square incli williout sand. % D.V.S. = Dry ing shrinkage, per cent dry volume. % D.L.S. CLAY RESOURCES AND CERAMIC INDT'STRY 345 5 B V .^ K UJ ^ c - ■ — ■ u en c P C I-. o s Z UJ c 3 CO 1 ■a .2 c p -1 CO n ^ e K IC j= bC r3 CO M u > ^ •"■ o j=: 1- o »o 2 a S -^ .2 ^ o o o o O s°: d CO c^ >o Oi cc O'^CO'-'C^O CO o o (^ »o "O r* I •00 CO O O t^ CI C-J • ^- c; cc CO c^i c>i CO C^ O T^ t-^ »0 O -* •b-CO .CD CO 00 OOOOO O T-lOO 'CO^00 'OO ,o^ OO CD 00 >— ' !>■ O (M ■ CO O CD t^ CO ^ I C^ — lO d lO lO I CO C^l (T-l (M "-< •f4-+^- ^ . -^ O I t CD OS ' ' t-t to^ «5^%OOOCMCDOI locDt-'S'Cv^LO OiOO .C^iOt-t-.-icoeoco*M co-^tM-— 'C^ OcDC^>D— iW i-t<-ti— 'COOlC^ •— OO-HCCM^rS-CDC^iOCn-^^C^cDOO M^C5^lOeOOCnt-Oi — CRC^COt^^-OOCOOJO: ..» ooo — — ooooO(Nt^te — r- — t- cOT)»'Oc^io«(NO:» »-;reto(Mt^co«;C'i'XJooirtr^t>jo doodr^io-* ocoiN to -* -;oo 2; 2°'"'^ "* " t-(M>OC-. « to -*-£-<• to Ot--*-* c^-»-ir:c-lC^)C~ltOiOQO0O — -tf-OC^OOCOCOOO-T^ otocsMMooocntocot-cor-woo racoco-rcocoCO^ OOira-3>tO — OtOCOiO — OC-. -•I-Q0-*0 — cote ^,-_H-^-.^tO«Si — - -- > *^ X A. \ No 21 ^ "V ►"^ ^. •»•• — — .- .S_ — -.-' ^^ ^ — A No 22 X X S_ •• "■ — ^^ ■*■ ■*■ - ^ A ^ <^ No 75 \ ^ — — ,*' <«« — _S -- — -" '"v \ 7 9 II 13 /S HEPCT TREATMENT IN C0NE5. HEfiiT TREATHENT IN CONES. 010 OB 06 O'tOZ I 3 5 7 9 H 13 IS" ft: i -J 30 20 /O o 10 10 -10 zo 20 10 \ A No 17 7 T~~ \ > ^— < x' 'S \ He Id 1 N /\ - _s. > ^ — . V \ ^^^ vA Nc -IS & s ^ N ... -. s. -- "'^ \ go 08 Ob Of OZ. I 3 5 7 9 // /J XT ^EAT TREATMENT IN CONES. HEAT TREATMENT IN CONES. CLAY RESOURCES AND CERAMIC INDUSTRY :U7 tt: i -J I I Absorption and linear slirinkape turves for clays of class 15. iy0 08 06 Of OZ / 3 5 7 9 II 13 /T Vl — r No 1 A — s. ■" s ^ < (^ No Z 10 10 ZO to 10 s S X -• • ' — >A ^ V No 4 ,s. ., > S A No 5 "~" — N • _s_ ,. ^^ 'X "^ - ^ s. No 6 ^ X ,« ^ 1 _ OlOO&Ob CH OZ I 3 S 7 S II 13 IS" ^ zoY ■^i 10 s 0^ — ft: ^ 10 |c -J ^ CiO •» §" 10 to I ^ 10 /f£AT TREAjn^NT IN COfiES. -, A Nd30 \ V S_ ^' >< N *-* A_ ^ s Nc3l S s * ^ ^ A \ No|43 _S > <; A Na60 \ S ^^ — ^ K A s No|ei s^ ^ ^^ OU-J-—; ^£/?7 TREATMENT IN C0NE5. OI0080(>0fOZI3579 II 13 IS 010 08 Ob Of 02 I 3 5 7 S II 13 IS" HEAT TREATMENT IN CONES. -J I I 30 20' 10- JO- 20 10 O- 30: 20- 10 No 18 4 A \ V. r*** JS ..' x \ No 16 5 A ^ V _S -'* /s \ A No 20 — \ ^^ *V — ^ — ^^ / X \ ^ J 'HEAT TREATMENT IN CONES. 348 DIVISION OP MINES AND MINING Absurption and linear shrinkage curves for olays of class 15. 010 Ob Ob (HOI I J 5 7 9 II 15 IS- -2 oc) 20 A No2l 1 1 >-> "m /o ^ \ %zo S. ^ \ •• ■• - A No £2 3 ^ V / / _s -- ,> i a o u >^ a La c o e o O -oft-' CO o <; c5 <• OS O c ^t: CO I o '• i < to 1 < 1 1^ 1 1 OS I c ^i 00 CO -*« CJ CO CO 1 loco 1 'MO 1 -co CO -* Oi CO lO ci ^ CO o < 'cooir- O O 00 Oi ^ r^-^ — eo w 1 eoc-j CO 00 -^o CJ ^ - o ^':; O t^ CI CO CO cTi c; t^ CO r^ o c^ Ci ^ CC - « t— OC 'T*- IM t^ CO CD Tf CD C^ CO IM CO "M CO CO CO '^ '^ CO' CO O: O ^ a; CO ^ (M -^ CO (M O CD 1 1^ o o c c O < t^ o ^ o »o r^ -^ »C CO in ^ ^ ^ (M C^ Class No.. . I^ + il CO 65 352 DIVISION OF MINES AND MINING Absorption and linear shrinkage curves for clays of class 17. . 010 08 0b m OZ I 3 S 7 9 II 15 IS" *o ^ 20 % Ci 10 Uj- '^ 30 ^ 20 ♦« /o IS ^ f:; 20 I ?, 10 /Vf/!7 TREATnfNT IN C0NE5. A ^ No 41 S A No 46 S ^ ^ V No II 5 N sA s — < \ y "s \ ■*^ \ < No 1 1 6 s Si "C" --- ... ^^ "5 s \ -^ i2 ft: -J OIC 08 Ob Of 02 I 3 S 7 9 II 13 IST 30 20 10 30 20 10 r No 16 3 — I A \ _s. ,'' s s A Nc 20 5 ^ ^ — s ... ,'' " 30 No 26 2 A_ _ 20 10 /■I "~* .. -- _S — — -- — -- //£A T TREATnFN T IN CONES. cJjAY resources and ceramic industry 353 chemical analyses. Table No. ;!() <;ivcs cliomieal analyses of ('crtaiii clays from (li'i)osits that were sampled and tested. About one-half of the analyses were made on a portion of the same samples that were tested for ceramic l)roperties and therefore can be directly correlated with the results of the tests. Tlie other lialf of llu' analyses were compiled from the litera- ture and from data presented by certain of the clay manufacturers. The sami)le nund)ers to which these analyses correspond are given in parentheses, but owino; to variations in the character of the clay being mined at ditl'ercnt times, the anal^'ses of the samples actually tested may be considerably different from those given in the table. Table No. 31 presents a group of chemical analj'ses of deposits that were not sampled. Very few of these clays have possible uses in ceramic manufacture, except for common brick. The analyses are given as being of possible interest in the future and to serve as a guide to the character of material to be found in the localities noted. 2:^ — .-,^07!> 354 DIVISION OF MINES AND MINING o a. Ui D a UJ _i < V) o oc u. i/i >■ < C/5 UJ ■ -I <' KK ^"xx x" X x"x" rersity R. XI R. XI ersity er. OO SS-5 2 3 O Vi Co., S. Co., S. Co., S. nford U nford U .\ngeles . s. e. 1 &Cn. . C. S. 6. 1 Stanford U & Co., S. . C. S., 6. 1 Stanford U & Co.,S. 1. Co. Stanford U . C. S. 6. 1 Stanford U Stanford U Stanford U Co., S. Co.,S. nford U: n&Co. . S. S, 1 >. ery & ery & ery & er, Sta er, Sta .s, Los I. A. C mery & mery & mer, Stai , McBea , .1. A. C, c W. Briggs, lith, Emery lith, Emery W. Briggs. J. Minner, idding, Mel W. Briags, W. Briggs, ith, Emery ith, Emery VV. Briggs, W. Briggs, W. Briggs. o ^ (at o K_; Minner, h, Emery Clav Proi Minner, hfiel, .1. A Minner, . Briggs, '. Briggs, 1 B s a = s s ■- e~.5fe~ h.E hficI ■Br h,E hfiel h. El h.Ei Mil ding hfiel. .^.-^.^^^u, a 1 t:; L !? "tiJ t; : 1 ^ ^^£;^ ^is .■^.ti~-^ £ s a a,^- ■„• 3 S3 .'a =! a a •- 3 a2Maj>>!i3m c/:' CQ O t/j CQ U* 1 cA' cu > 03 > a o cococpa oaiooor--oooo;ioooo — • o OS :o -^ o o O - O^O; 0050000COOOO IM O CC (M OS O O kO — O Ol C) CO OQOiOOOOV "O oc O CO oc o oL OOOOOOOOOOi ooo o o o o o o o O O O CR O 1 _ 1 O 05 r!i CTi C!!5 -(N u:if^ o 05-* CO CD CO Oi iJCO "ti CM I^CM £ T-i o CO cor-- >— " 00 Tf ^c^j.-o^ oo ^oo O O C5 -^ ^ ^ O 00O5 — o CI O O o o 't ^- CO C^l lO — O '^ o a: cc M- — t^ o — 3 O.o ^ . - . ^ ... .... " " " — r~ " " Cv| -■ w . . oc " rt- « o — =• *o-* — " ** 'i w'^^ o o — o c^ ooo odd o M*»00 .•;0'*:f .• .■ic»oco»— «o O (U . • CO ■^ -^ l" X t-' fc-' t-" J2 r^ L," ■^ ij tJ ^o o oo — — o .• — »0 CO lO i CO 1 OiCC^^i— CO^ci^OOOC^lO IT s"^ ooo OO ooe>oo o a ooo o o c o ooo ooo d CO OO Oi -^ ^ — ' -ff Cr- »0 1 I^ o »o O 00 -* OO O — — O O C^ c Cfi CO O CO iC o — o o o « 00-f-f^G0C000iMO5t--ir:»OO 1 -* C-. ^ O 00 , • CO ! . 1 c: . , a>io c: 'oT'^ o 1 1 1 ' C . 3 3 ; s o , E-102? ;o Co. . - d O a; c a Co.... aolin (med.). (soft).. 0. -a . Co. Scl. M Co. S. H.-3 . Co. M. T. .Mfg. Co.. H s 1 1 COM , Bone. ay 0. 26 bo iloan No 'a 3 .a bO CD bC c: 2 o 2^ CI. Q o o 57^ £ Nevad; eked k; No. 2 No. 3 eras C a _ _ _ 2 o d i Q- rt 6 6 o-Z"J s 6 o" OO id o ^^ s § & H ^d^i o d*^" . d =B"8 5 am jj ^j TO t- W .yaggjiw » o t^ ■J-' t^ a> L. t- .. Lh h- O) O CJ OJ QJ <1 j£|lil.B| fefc^^ fe £^^ i^ rt rt-^ .aj= aXiSi c: <<-c (^ t-, to ^ — — CM OS COCOCM iple — (M , >. >. >.>, x' X !>■, *x >. •^ i-.^ •gi- i' ■»;■» ><.^ 1 >, Xi? '^ fc« ■1 1.1 fc- ■-* k- h. k> > >t jl.ll oig «l 'H > \ y = > > "2 1^1 == ^ ^ '=^ ^ Uj-= '■•^Ui Sn •= 2 L- .*« :_> T3 :^^ '— — t^' •^.^ d "^-? t-i - l-o i ■-, ^ •S'2 «,- §-^ - t O ~0 5C-' ' c Vh U- ^ ^ 1 • fca k. 1 **•* 1 CO . 3 CO 3S d^ 1^ 3 5 rt o.o d a •2d «i d 2" d ti i B : CO jT _- ojco <-B' -st- -c'^' o C- pa "S "i-s -<• •? |Ih..h 1 .^ e9 OS 3 'C .2 .Si to to -'^i -£11 '■£■£ -1 1^' (i; ^ k. .2 -E-C _- >. c3 .H-n a ' C Sj OC C3 >. c >» - -- >i b n Q con ;g.2PQ Qaam :a5 = P3 C3 So 1 o QCQpa<; ^ - b- ' ' - -^ fflaJui isd^ ■sis' 7^ i^ Jd <£ .03 3 «S co> ^'uiuiJ t* § r* — olc^ooo otoo ■^ — CO O CMO -•. ! d OS •*" ?o 1 Oh- 1 Oi O o O o 00 coo 1 »0 -H O iC o o 1 S-. ^ =i O OO ec 1 h* ■«!f CO OO O 05 1 OSO o o o o OO OO'ioscsO CICC: o o C: O 1 d O 1 2 ' O Ci CS OS o d d OO o c o 35 OO'CiClO ClOO OO — . O 1 O O loo O CS 0-. OiO OO ^" ^^ ^" '"' t ^" — ^- "" "" — 1 1 ^ *~* ^^ 1 1— 1 .-. - ■* CO C-. O COlO 1 o a> ■* CO c-i OCO S: CI U50 ?o CCOO CO -^ 030 t^cco o- lOO eC> — d — lO d -^o c^ o OO OCl _ CO »o -^ CO t^ O cr. -rj. --c • 0-. O 1 CO 00 -i^ coco CI -* (M (M -^ M — ' (M (M C^ !M rr CMci CI -* O^H "* t^OO lO »o h-t-^ eooics — 1 *-* C5 CO Ci coc'ic--ro« csc^ioo' mo — O |l 05 00 OS— M OO OS CO d -* r^ ci 00 C>) (TO ^C«i|t^OOCi CIClCO ^lO — 1.0 |l coc» •r r^oo CI o — ^ ooo d CO OO C5 (M — (N 00 05 lO O 00 CI 1 CO CO CI -^ 1 [ CD CM j OO t^ -^ OS — lor^ deoooci T-J CI CO ccco CM CMCO CO CMCM . CO CO CO CI ■! — CM — c^ .- CM — CO C) CI — c» II 1 1 »c to CJ 00 00 !D!Ot~ OOO CR»0 ooc^ Hot* o -*t«oo w o 1 t^^^ O-^CDiO 00 CO lO CO '-^ CO 1- M ^ iO t^ C5 COCO O -^00 COt^ I f5 CO ^ CO Isd is.;; dQS^ '2 b ; ;- ; ;2 o :s d d . d d^ 2 J -5) i Q 1 d 2 1 d O o • 1 1 : ■ t < o c Z o" o d d • d :z I d 2 id . :o & is a is > 03 II fe^ ii";^© IcS" d-« •3| ■a 09 'S 6 a ; •S.S 0-3 1 ' ^ 00^ 'v o; &; ;CU PM ;s «■&; &&; ij^s ddS ;ii-«l fc CU m3 p^^^a d d |d d ;ii ^"•■^d idf d d ^1 . CC CD ^ .. a ,j CJ -; ' » cj:— Jj'd a! ft-' .1: s ..5.S a coin: coin: ^i-^-r: r:c;-ii5^C^ -f-f-i ^.ii'il' fe > ? o — o v;ccco g . g o o o — m C M C "S II-- «3=2~ -O -^ C 1! .s-s-sj ^^1! 12 J ■^ jIj i-j K |! <->: <: oa<: -H- j>>s: ^^ __^ ^____, ^^ ^ ^_^ || ^,^^_^ ll ^.^ .— v.— . >— S-— . ^_^ "5 lO o O CO,i— OCCCi Ci-^: o r^ r^ ci,|^-l lOO o CI CO t^CM OOCl CO o TT -^ »o lO izO'O^ffO'Tl- 't^O' -r -f>.o CO-* O ^CM -*oo — " II -* CI CI CI "— ' II •-^•— '^-^ -— ' ■— ' ^•^ ■-^ •^-^-—' ll 1^ 00 :'=» It o 1 c»» 1 n II •^ 11 II II — II 1 " II 1 a E a. S B O Qi CU ^S o o = a 2 o GO a a o C.B en C Gi B C I. V s.^ S a S o STte o II ^"c.^ S E >. O E 3 J . a X „ tfi "^ c-=S i E g 3 ^6 *^ X r^—* CI o d2 II cS fc --^ s o ^gE^i C CO ft.5 356 DIVISION OF MINES AND MINING a 111 a ^ J2 Q. 9 S < CO ^ 3 1- o z s (n X > P < -1 C3 o C 03 < "3 z c d o f:i u. o _l < o at 3 O liJ 111 u CO a> 111 CO >■ < Z < _l < i 111 z o as ^ ^ t:^" ^ -< l^d h^ t^' ^' iii i^ >:d ^" Ui ni t^ ^* t^n' t4 ^ iii t:d t o o >< X c =: a c c c: c *- ^ C* i, ' ; :^ *^ ^ ui iii lii ui tii ui t:d tij ui ui t4 ^ -J _• __• CC (Tl lO X - s s »c 00 r^ =3 :3 3 3 cj -c ro ■^^-t~*'?':CfMn— -icio-^ooo- ^ Soo O i;'H'x"5*^ — "S i;"S"2 — "5"2'^"5 — "9 =; ^ — "H — x^"^^^^-"x'^oo'x'^'x"^ c-c-c-^-^-3- 3 -^ C-1 C-l O i.*^ CC CO t* — C^l <-« 303 3^ P^OOOO — ^C^C^'^C^— 3 " ; iC O r. OC OC C^J l>- CC 3 lO — -?■ — cc oo :^ o c^ M r^ 4f: -^ 00 -^ •* t-- c» t~ r-- — t-- t^ ;-ri^>f; — c-i'^»ct^c:cr. oow-^occcac*--:; o o Z a bl -1 S CD a < -Cede o o o o o c: c >>>.>>>. >.o o c c c c c ^ >> eS C3 cS ed c3 e c ^ ^ . . . wO ^^^^ZSS:5S O -u--=: c c3 ZZt. L. L. L- L. af^X. « ; z. a. '^ "" X -r, X "-- ~'-:::*3 ^' " ^-^ C C-i s ^' ^lifc^i. i-«';"5t-- t-t: =c £«ffli2i5i55a2SK'S2S g > > w OS 09 9 9 9 S ^ ij s_ o w> cj ;z; ^ ~^ ti u t^ — t- t- C S- t- t- — — ^ t. t- — SSScocc — ■ :^^ Jcc wC^w — SS2^ :s;z t: = -i5 5 '^ -#= = 63 S-^ =- i -Is w _^<; 2S: ; rt ci :i «^ : rx 31 £- Ch ;z; q E x X X X a: 5 r5 O O O 0-0'^'T3'Ct3'Ct3"3 "3'C ■— -— -^ ■— 5 5 , , •' " ■"■": -^ _3 . " T , "^ . " C C C C CJ o cj CJ Ci o ii c Cj C- ^ J J^ f .— — — X X X X X X X I. X X — — ._ — , aocjoowtJuocjrT-r r ■"; ""= 3 -—■—•—■—■—•—•—•—•— ■— — «- — >-t-i-fc,fc-t-t-t-(-»-i- — — — — „_, — — ■- — — — — — — •- — - a c ^^ S X X ^ 6? O CLAY RESOURCES AND CERAMIC INDUSTRY 357 INDEX OF CLAY SAMPLE NUMBERS ^§1 4 CO r* ?g- ?«-! m ■ to 1 ^ ■a at •a a. 253 13 •Si »g- : f^- ; F ; '5.'"^ : f • 5^ ; F ; H.'"^ ; S ; v-^ ; -^ \ f 1 5" , _3 * i 1 1 f i f 1 218 338 59 265 111 176 315 162 159 223 141 343 2 218 338 60 " ioo" 340 112 178 324 163 159 "m 229 175 300 3 218 348 61 102 341 113 178 324 164 150 230 175 300 4 234 338 62 145 259 114 90 312 165 159 231 175 281 5 234 339 63 140 260 115 90 349 166 138 "316" 232 175 281 6 234 339 64 140 260 116 90 349 167 138 315 233 70 7 169 328 65 141 322 117 131 324 168 136 313 234 70 8 169 3^1 66 179 277 118 192 341 169 138 313 235 70 """263 9 169 287 67 179 277 119 74 325 170 136 315 236 68 263 10 169 334 69 169 323 120 53 272 171 136 329 237 68 263 11 169 257 70 169 272 121 53 302 172 136 342 238 70 316 12 169 257 71 169 278 122 53 328 173 235 313 239 52 281 13 169 296 72 169 328 123 56 335 175 65 304 240 52 274 14 169 287 73 169 323 124 56 302 176 66 325 243 52 15 169 264 74 175 278 125 53 273 177 66 336 244 52 "281 16 169 314 75 175 335 126 52 279 178 65 325 245 52 300 17 169 277 76 175 288 ; 127 57 335 180 77 326 246 52 300 18 169 321 77 175 278 128 54 261 181 80 336 247 52 300 19 169 311 78 175 288 129 62 261 182 81 326 248 52 301 21 169 334 79 175 278 130 62 290 183 81 326 249 52 301 22 169 335 80 175 297 131 62 329 184 80 342 250 52 282 23 169 277 81 175 289 133 63 298 185 80 342 251 52 327 24 169 321 82 175 315 134 58 261 188 92 336 252 52 305 25 169 311 83 175 297 135 58 312 190 133 261 253 52 301 26 169 321 84 175 289 136 58 302 191 133 280 254 52 301 27 169 287 85 175 298 137 57 266 192 133 281 255 52 313 28 169 264 86 175 279 138 57 280 194 227 262 256 52 330 29 169 264 87 175 279 139 57 290 195 227 262 257 52 291 30 203 339 88 315 140 56 280 197 227 291 258 52 292 31 204 340 89 341 141 58 280 198 125 329 259 45 263 32 205 322 90 "173" 265 142 58 280 199 74 326 261 159 328 33 205 287 91 173 260 143 185 274 200 73 342 262 159 350 34 205 288 92 173 289 144 185 273 201 69 305 263 159 292 35 202 322 93 173 265 145 156 291 202 68 337 264 42 343 36 201 311 94 173 311 146 156 303 203 68 337 265 40 343 37 201 259 95 173 311 147 156 303 204 68 299 266 140 292 38 201 259 96 173 272 148 156 336 205 229 349 268 140 260 39 203 296 97 173 290 149 156 298 206 232 327 269 316 40 203 322 98 173 272 150 156 291 208 57 262 270 "140" 282 41 202 348 99 173 312 151 156 303 209 59 263 271 169 301 42 181 340 100 173 323 152 147 304 210 186 337 272 169 292 43 181 340 101 173 298 153 147 299 211 81 342 273 169 273 44 196 264 102 173 290 155 151 325 212 186 337 274 169 302 45 196 264 103 173 260 156 151 299 213 59 299 280 147 305 46 195 349 104 173 279 157 151 304 214 131 327 282 141 282 53 195 288 105 173 324 158 138 216 213 327 283a 232 314 55 195 314 108 176 290 159 137 "261 217 213 327 283b 232 314 56 297 109 176 266 160 137 261 218 181 329 284 232 316 57 "194" 264 110 176 298 161 159 221 141 330 285 232 282 358 DIVISION OF IMINES AND MINING INDEX TO CLAY SAMPLES, BY COUNTIES County Name of property Designation of clay CO » B •a. p 03 p Description of property, page -9 W. S. Dickey CM. Co M & S Tile Co. Niles __ 265 264 259 15 15 1 40 42 45 343 Niles Tesla 343 263 Arroyo Seco Grant • Baker 126 125 120 122 121 240 245 247 246 248 249 250 251 252 253 254 255 239 256 258 257 244 243 128 124 123 5 4 3 13 8 4 7 7 7 7 7 5 12 8 7 7 9 5 13 6 6 5 8 14 52 53 53 53 53 52 52 52 52 52 52 52 52 52 52 52 52 52 52 52 52 52 52 54 56 56 279 Gage 273 Jones Butte fireclay Jones Butte laterite 272 328 .Tones Butte 'unctuous'.. Lot 237 E. side 302 274 Hole 55-1 300 55-2 300 55-3... 300 56-1 .301 56-2 .301 56-3 282 57-1 327 57-2 57-3 . . 305 301 57-4... -. .301 57-5_ Lot 254, N. E. cor 313 281 Lot 255, Hole 60 61 330 291 62 Lot 324. Hole 54 Lot 336, Hole 47 292 281 Shepard sand 261 Yaru No. 1... Yarn No. 2 302 335 Bacon and Bacon Bacon blue.. 139 138 127 137 6 5 14 2 57 57 57 57 290 Bacon bottom .. _ 280 Bacon red 335 Chocolate 266 Carlile N. Clark & Sons Carlile sand 208 134 136 135 213 209 141 142 140 130 131 129 133 1 1 8 9 7 1 5 5 5 6 13 62 7 57 58 58 58 59 59 58 58 60 61 61 61 63 262 Clark sand . 261 Eckland Fancher (W. S. Dickey C. M. Co.) lone Fire Brick Co Newman Estate Yosemite Portland Cement Co.. Dosch Doschstripping 302 312 Mottled 299 Sand 263 Fancher yellow 280 Fancher )lue 280 Sand 280 Carbonaceous sand .. 290 Pink mottled 329 Sand .- Harvey 261 298 Butte Lund Ranch Common. Common 178-1 -2 -3 177 176 175 12 12 12 14 12 8 65 65 65 66 66 66 325 Oroville-Quincy Road.- Table Mt. C. P. Co. 325 325 336 Decomp. igneous. Yellow plastic... . . .- . . 325 304 Calaveras California Pottery Co. Nigger Hillkaolin' Nigger Hill'kaolin' Valley Spgs. blue Valley Spgs. pink-mottled Valley Spgs. yellow Helisma.- 236 237 204 202 203 201 238 233 234 235 1 1 7 14 14 8 10 68 68 68 68 68 69 70 70 70 70 263 Helisma Penn. Min. Co Texas Min. Co.. 263 299 337 337 305 Kaolinized schist 316 Kaolinized schist.. Kaolinized schist.. Kaolinized schist. 263 Contra Costa N. Clark & Sons Walnut Cr. shale Shale . . 200 199 119 15 12 12 73 73 74 342 Port Costa Brick Co. 326 RichmonH P. R. Cn Shale 325 Del Norte .. . Musick Common 180 12 77 326 Humboldt Angpl R.anp,h Pottery (red)... Common Common Common _ Common 181 185 211 183 182 14 15 15 12 12 80 80 81 81 81 336 Loof bourrow Strong's Station Sunny .Avenue Thompson Brick Co 342 342 326 326 fl.AV KKSOrRCES AND CERAMIC INDISTRY INDEX TO CLAY SAMPLES. BY COUNTIES-^Contlnued 351) County Name of property Designation of clay i p Description of property, page Class No H ; 5 Amer. Silica Co Death Valley superfine 269 10 316 Merrv Widow Mine Impure kaolin 115 116 114 17 17 9 90 90 89 349 Titus . . Impure kaolin.. . 349 Titus 312 Lake Keiseyville _ . . . Common 188 14 92 336 I.nR \nceles Da\i(ison Brick Co. Common 60 61 15 15 100 102 340 Gladding. McBean & Co Santa Monica common 341 Msrin McNear Brick Co. Shale _... 198 13 124 329 Area. Common 117 214 12 12 130 131 324 Monterey Mission Tile Co Adobe 327 Clark and Marsh Kaolin, average- 190 191 192 1 5 5 133 133 133 261 Kaolin, selected 280 Kaolin, lower tuimel 281 Nevada Banner Mt. Road 170 168 172 171 159 160 166 167 169 158 10 9 15 13 1 .1 10 9 136 136 136 136 137 137 138 138 138 138 315 Beascr Ranch 313 Pipe clay 342 North Bloomfield Rd 329 Pine Hill Mine Kiinlin 261 Sonntaff Ranch Kaolin . 261 Kaolin.. 316 Kaolin 315 313 Sweet Ranch (Pine Hill) Kaolin Amreco fireclay 266 270 268 64 63 65 221 282 223 62 6 5 1 1 1 12 12 5 15 1 140 140 140 140 140 140 141 141 142 145 292 Brea C. P. Co. .\rc fireclay 282 1^1 Toro crude . 260 Hunter Ranch — lower Hunter Ranch— upper Common 260 260 322 Gladding, McBean & Co Vitrefrax Co. Goat Ranch flint 330 Goat Ranch flint 282 Goat Ranch shale M M 3 O'Neill Ranch fireclay 343 259 Placer Clay Corporation of Cal Gladding, McBean & Co Lincoln C. P. Co. Lincoln fireclay 280 152 153 156 155 157 145 146 147 148 149 150 151 165 162 163 164 161 261 262 263 8 8 7 7 12 8 6 8 8 14 7 6 8 ■"17" ""\2 17 6 147 147 147 152 152 152 156 156 156 156 156 156 156 159 159 159 159 159 159 159 159 305 Lincoln top clay 304 299 Lincoln fire-proofing 299 325 Lincoln terra cotta 304 No.O .- 291 M iacellancous No. 1-6 303 No. 7 303 No 8 336 No.9 298 No 10 291 Washed china clay 303 Alta Baxter Baxter . 350 Baxter Kaolin (impure) 328 350 Kaolin (imoure) , 292 Pivprfltdp Alberhill C & C Co A-clay . 14 17 18 11 12 19 9 271 272 274 10 29 13 15 27 6 5 12 1 1 9 6 7 6 7 14 2 7 2 6 169 169 169 169 169 169 169 169 169 169 169 169 169 169 169 287 Bone W-105 277 Clark tunnel mottled China E-101 321 257 China E-102 257 Diamond 311 Hillblue 287 Hill blue, lower tunnel Hill blue, main tunnel Hill blue, upper tunnel 301 292 302 3.34 264 Main tunnel ex. select Ma.in tunnel select 296 264 No. 10 287 360 DIVISION OF MINES AND MINING INDEX TO CLAY SAMPLES. BY COUNTIES— Continued County Name of property Designation of clay CD B •3, p o »" CO p Description of property, page : ? Pink mottled.... 7 8 21 28 273 23 16 25 24 26 22 13 12 14 2 3 5 10 9 12 12 14 169 169 169 169 169 169 169 169 169 169 169 328 Red No. 2 321 Sagger. 334 SH-3.. . 264 SH-4 273 West blue 277 West blue select 314 West tunnel blue 311 West tunnel mottled. 321 Westyellow.. . 321 Yellow Owl Cut... 335 Emsco Clay Co. (Harrington pit) Bone. -. 73 71 72 69 70 12 5 13 12 3 171 171 171 171 171 323 Pink mottled 278 Red. 328 Red Horse... . 323 White (No. 5) 272 Gladding, McBean & Co. (Alber- hillpitB) Bone (W-105?) 98 90 93 91 92 96 103 104 105 102 101 97 99 94 95 100 3 2 2 1 6 3 1 5 12 6 7 6 9 9 9 12 173 173 173 173 173 173 173 173 173 173 173 173 173 173 173 173 272 Main tunnel.. 265 Main tunnelselect 265 Main tunnel sand 260 Main tunnel yellow.. . . 289 No. 10 272 Sloan, bone . 260 Sloan, No. 5 279 Sloan, red.. . 324 Sloan, sand . 290 Sloan, white 298 Smooth bunker 290 Tile.... 312 West blue 311 West blueselect 311 Yellow stripping 323 Hudson Ranch- Clay. .. 89 88 15 10 341 Sand 315 Los Angeles Brick Co Bone, high-alumina 231 87 232 82 229 230 78 77 76 81 86 85 84 83 75 74 79 80 5 5 5 10 7 7 6 5 t 5 7 6 7 14 5 5 7 175 175 175 175 175 175 175 175 175 175 175 175 175 175 175 175 175 175 281 Bone, smooth Bone. smooth . 279 281 Clay shale . 315 No. 7 300 No.9 300 No. 10 288 No. 20 278 .No. 23 288 No. 25 289 No. 26 bone 279 Pink mottled 298 P. M. fireclay 289 Red 297 Red No. 2 335 West bone 278 West pit fireclay 278 West pit mottled ... 297 Pacific C. P. Co. (Alberhill and Corona pits) Douglas . 110 111 109 108 112 113 67 66 7 10 2 6 12 12 5 5 176 176 176 176 178 178 179 179 298 Douglas lower 315 Douglas main tunnel Douglas upper. . 266 290 Hoist pit blue ... 324 Hoist pit red. 324 McKnight fireclay. 277 McKnight sewer pipe 277 Temeseal Water Co Pink mottled . . 218 42 43 13 15 15 181 181 181 329 Wilson, J. W Common.. . . 340 Common 340 Sacramento Michigan Bar. . Cutter 143 144 210 212 4 3 14 14 185 185 186 186 274 Natoma Clay Co Van Vleck.. 273 No. 1 . 337 No.3 337 CLAV RHSOIHCES AM) CERAMIC IXIHSTHV INDEX TO CLAY SAMPLES. BY COUNTIES— Continued 861 County Name of property Designation of clay ■2. p Q p Description of property, page ; f Paicincs Common 118 15 192 341 Hart kaolin 57 55 46 53 44 45 2 10 17 6 2 2 194 195 195 196 196 196 264 Gladding, McBean & Co Bryman clay _ .. 314 Impure kaolin 349 Millet & Kennedy .. Buff-burning Pacific kaolin (Hart) 288 Standard San. Mfg. Co. 264 Pacific kaolin (Hart) 264 San Dieffo California C. P. Co Cardiff fireclay 36 38 37 35 41 39 40 30 31 33 34 32 9 1 1 12 17 7 12 15 15 6 6 12 201 201 201 202 202 203 203 203 204 205 205 205 311 ElCajonMt Kaolin, ayeragc 259 Gladding. McBean & Co Morris.H. T Kaolin, selected.. . 259 Cardiff 322 Common 348 Pacific C. P. Co. Kelley Ranch white 296 San Diego T. & B. Co... Kelley Ranch yellow 322 Rose Canyon .. 339 Rose Canyon 340 Vitrified Products Co. Cardiff fireclay 287 Cardiff fireclay. 287 Linda Vista shale 322 San Luis Obispo Santa Margarita Shale 216 217 12 12 215 215 327 Shale 327 S:\nt.a Barbara Brentner Carpinteria 3 1 2 17 15 15 218 218 218 .348 Muegenberg& Whitiker. .- Santa Barbara 338 Toro Canyon . 338 Beltane.- . Buff -burning 197 194 195 6 1 1 227 228 228 291 Weiss J. H. Average white . 262 Selected white.. ,. 262 Cummings Ranch Shale 205 17 229 349 Tulare Sears W. A. - Kaolin (impure) Kaolin (impure) 283-A 283-B 284 285 9 9 10 5 232 232 232 . 232 314 314 Kaolin (impure) 316 Kaolin (impure) 282 Valencia Heights Shale . 206 12 232 327 Anderson & Hardison (Santa Paula) Blue 6 5 4 15 15 15 234 234 234 339 Peonle's Lumber Co. 339 Yellow 338 Yuba Demnsey Ranch Kaolin (impure) 173 9 235 313 Florida Edgar koalin 59 59 2 7 265 Germany Fireclay . .. .. 297 GEiNERAL INDEX. A Page Abbe Ranch 192 Al)rasives, clay suitable for_- ._^ , ^^ 253, 254 Absorption . ^» ^^. ^^ . 245 Acme Brick Comi>any ^_^ ^_. . 94 Alameda, plants in 40 Alanifda County 38 clay resources 38 bibliography 49 Albany (see Berkeley). Albany slip, use of . 49 Alberhill 162-163, 175-17G, 178,180 clay, use of 93-98, 100, 101, 104, 107, 109, 117, 118, 119, 123, 215, 216 Alberhill Coal and Clay Company 162 clav deposits 169 clay tests 257, 264, 273, 277, 287, 292, 296, 301, 302, 311, 314, 321, 328, 334, 335 Alberhill-Corona district, description of 162 Alhambra 94 Alhambra Kilns, Inc. 94 Aliso Creek 139 Alpine Quicksilver Mining Company 192 Alta, clay near 159 Alumina, high, clay (see bone clay). Aluminum oxide 121 Amador County 49 clay resources 50 bibliography 63 Amador Kaolin Company 63 Amargosa River 88 Amboy, bentonite at 97 American Ceramic Society 238, 244, 252 American China Comjiany 94 American Encaustic Tiling Company, Ltd. 95 American Portland Cement Company 85 American Pottery Company 201 American Refractories Company 96 Amreco fire clay, tests of 292 Arc fire clay, tests of 282 American Silica Company 140 Death Valley clay, tests of 316 Hunter Ranch clay 140 Robinson Ranch clay 140 Amick, "W. D., property (lone) 63 'Amreco' fire clay, tests of 292 Anaheim 144 Analyses, chemical, tables of 353-356 value of 252 Andalusite 19 Ander.son 223 Anderson, Andres 187 Anderson, Mrs. A. E. L. 107 Anderson, H. P. 92 Anderson Ranch 92 Anderson and Hardison 234 clay, tests of 339 Angel Ranch clav 80 tests of ^ 336 use of 39 Angels Camn 68 Angulo, R. F.. and Sons 97, 218 Angulo Tile Company Plant No. 1 218 Plant No. 2 97 Antioch 75 Area, Joe 130 clay, tests of 324 Area roofing tile plant 130 Areata 79- 80 Architectural design 29 Armstrong, H. C. 105 Arnold, Ralph 222 Arrovo Seco Grant 51 clav, tests of 261, 272, 273, 274, 279, 281, 282, 291, 292, 300, 301, 302, 305, 313, 327, 328, 330,335 core drill samnles 52 Art pottery, manufacture of, in California 30 Art ware 38, 39, 45 Ashbury, F. A. 227 Atlas Fire Brick Company 97 ganister 194 Austin, L. ^:V. 221 Axelson, Victor ^^__.,„,^.,_,^,_^__J 187 INDEX 363 B Page Hachman, W. E. 98 Bacon, M. J. 41, 56 Bacon and Bacon 51, 5(i clays, tests of 266, 280, 290, 298, 3:i5 Bacon Red pit (lone) 57 Baden Brick Company 215 Baker, A. A. 220 Baker, Joseph 40 Baker, Levi S. 40 Baker Clay, tests of 279 Bakersfield 89 Bakersfield Rock and Gravel Company 89 Bakersfield Sandstone Brick Compan>' 89 Ball, Chas. 40 Ball clay, definition of 15 resources of, in California 19 Bane, T. H. i:il Banner Mountain Road clay 136 tests of 315 Barber pit (see Shepard pit). Bardin, Martha E. 132 Barstow 19 Batchelder, E. A. 97 Batchelder Tile Comiiany (see Batchelder-Wilson Company). Batchelder-Wilson Company 97 similar product 42 Bauer, J. A., Pottery Company 9S Baum, J. W. 252-25:! Bauxite 20 Baxter, clay near 159 Beaser, P. M. 136 Beaser Ranch clay 136 tests of 313 Beckman-Linden Engineering Corporation 42 Belgian sand 20, 28 economic factors 51 Bellota 207 Beltane 227 clay near 227 tests of 291 Ben All 183 Benicia i 225 Bentley, Arthur 78 Bentonite, Amboy 97 Berg, C. B. 73 Berkeley, plants in 38-40, 42, 45, 49 Bethany 207 Bettencourt, J. M. 41 Betteravia 217 Biddle, C. J. 121, 162 Biggs 66 Birtolini, G. 208 Bishop Canyon 104 Bisque doll heads 38 Bitterwater 192 Blake, W. P. 84 Bleininger, A. V. 240 Boggs, G. Ray 96,140 Bohannon Ranch 66 Bolflng, Chas. 220 Bnlinas Bay 124 Bone clay 20, 29 Bonding strength 241 Bonistell, C. E. 234 Bonner, J. M. 123 Borego Mountain 83, 84 Boving, P. C. 103 Bovvers. Stejihen 140 Bovles Heights Terrace formation 107 Bradbury. E. R. 142 Bradlev, W. "SV. 13 Bragdon, W. B. 39 Branner, J. C. 222 Brawley 83 Brea 140 Brea Clay Products Company 140 dav, tests of 322 Brentner, L,. L,. 'IS clav deposit 218 tests of 348 Brick, common, clays stiitable for 255, 256 Brick, statistics 31 Brick handling machines 26 364 INDEX Page Bridge House : 185 Briggs, C. W. 13 Briggs, U. N. 126 Brooks, Max 66 Broughton, H. W. 99 Brown, II. M. and R. W. 121 Brown, J. S. 84 Brown, Wm. 60 Bruns, L. H. 221 Bryman 195 clay, tests of 314 Buchler, A. E. 92 Buena Vista 50 clay deposit near 58 Buff-burning clays, tests of 277-320 Builders' Supply Company 218 Bundock, C. E. 185 Burchfiel, B. M. 13 Burning (see firing). Burress, Mrs. I. M. 41 Burson (see Helisma). Butte County 64 clay resources 64 undeveloped deposits 66 Butte County Farms 67 C Calaveras County 67 clay resources 68 geology 68 Calaveras formation 50, 68, 70 California Art Tile Company 72 California Bisque Doll Company 38 California Brick Company 40 California Brick and Tile Company 98 California China Company 38 California Clay Manufacturing Company (see Los Angeles Brick Company). California Clay Products Company 99 Cardiff clay 201 tests of 311 tile, use of 95 California Faience Company 39 'California Mullite" 122 California Pottery Company 39 Merced plant 128 Nigger Hill deposit 68 Oakland plant 39 Valley Springs clay pit 68 clays, tests of 299, 337 California Pressed Brick Company 40 California State Life Building 185 Calistoga 132, 133 Campo 19, 201 Campo Seco 68, 70 clay, tests of 316 Cannon, D. A. 183 Cannon and Company 183 Capay 235 Carbofrax, use of, in test kilns 243 Carbondale (see lone). Carboniferous 50, 68, 70, 84, 200 Cardiff 200, 201, 205 clays, tests of 287, 288, 311, 322 use of 99 Cardiff-Carlsbad district 19 Cargo Muchacho Mountains 83, 84, 87 Carlile, Mrs. Sarah E. 57 Carlile clay and sand pit (lone) 57 Carlsbad 200, 203 (see also under Cardiff). Carmel 131 Carmel River 129 Carmichael, W. J. 144 Carnegie 207 clays, extinct operations 45 'Carnegie' brick 209 Carnegie Brick and Pottery Company 45, 208 Carpinteria 218 clay, tests of 348 Carquinez Brick and Tile Company 76 Carrizo Mountain 83, 84 Carson Hill 68 Casting (of clay ware) 16 Castroville 130 INDEX :](]') Page Cazadero 226 Celito Products Company 30 Cement, use of lone sand in 51 CfHienl induslry 31 Chemical analyses, tables of 353-35U value of 252 Chemical ware 21 Cherokee 04 Chicago Park 136 Chico 200 Chico formation 18, 64, 126, 139, 141,215 China clay, definition of 15 resourc'i's of, in California 19 Chocolate Mountains 84, 85 Chocolate pit (lone) 57 clay, tests of 266 Chown, J. V. 236 Chroma 249 Chrome brick 21 Chualar 132 cMma 195 City Brick Company 100 Clark, A. V. 40 Clark, G. D. 4(i Clark, J. R. 133 Clark and Marsh kaolin 133 tests of 261, 280, 281 use of 38 Clark, N., and Sons 40 Alameda pottery , 40 lone properties 58 Clark sand, tests of 261 clays, tests of 302 clay washing plant 50 Walnut Creek shale 73 tests of 342 Clay, classification of 253 by color 251 by modulus of rupture 241 by ratio of pore to shrinkage water 240 by refractoriness 248 definition of 15 field tests of 237 high grade, California, geological age of 18 laboratory tests of 238 preparation of 15 products, statistics 35 samples, list of tests on 258 tests, buff-burning 277-320 dirty white-burning 348-352 red-burning 321-352 white-burning 237—276 use of, in oil wells 234 washing (at lone) 50, 57 Clay Corporation of California 147 clays 151 tests of 299, 304, 305 use of 60 Claycraft Potteries, Inc. 100 Clay-Worker 121 Clear Lake 91 Cleghorn, P. T. 209 Clemson, G. W. 121 Clinker Brick Company 91 Cloverdale 227 Coal Canon 67 Coast Fire Brick Company 76 Coast Range (see under various counties and individual ranges). Coe, Ira J. 137 Colfax 135 Color 248 classification of clay by 251 common names 249 Munsell's standards 250 Ridgway's standards 249 Ridgway vs. Munsell 250 variables of 248 Columbia Cement Company 85 Colusa 71 Colusa County 70 clay resources 71 bibliography 71 Common brick, manufacture of. in California 26 (Common brick clay, definition of 15 occurrence of, in California 17 300 iNDT':x Page Common hrick plants 21 Conduct omoter 211 Conduits, clays s-uital)Ie for 255 electrical, manufacture of, in California 27 Cones, pyrometric, end i>oints of 244 use of, in softening point determination 246 Conger, A. A. 105 Contra Costa County 71 clay resources 72 extinct companies , 76 geology _ 71 Cook, T. P. 121 Coors, H. F 100, 194, 260, 264 clay in Hart Mountains 194 tests of 264 use of 100 Coors, H. F., Company, Inc. 100 Core drilling, on Arroyo Seco Grant 52 Corning 231 Cornish stone 95 Corona (see also under Alberhill) 162, 169, 179 Corral Hollow 42 Costello, F. A. 39, 128 Costs, mining and transportation of clay 21 Cosumnes River 182, 185 Cotati 227 Cottonwood 223 Coyote Creek 139 Coyote Creek (Santa Clara County) 219 clay 219, 220, 221 Coachella Valley 84 Crampton, J. T. 119 Craycroft, F. J. 78 Craycroft brickyard (Modesto) ; 229 Craycroft -Herold Brick Company 78 clay, Merced 128 Creegan, J. F. 39 Crescent City 76 clay, tests of 326 Cretaceous 18, 38, 64, 72. 73, 79, 127, 139, 141, 161, 191, 200, 207, 213, 215, 217, 219, 225, 226, 229,234 (Slee also under Chico formation.) Crucibles, graphite, clavs suitable for 254 Cubach, O. J. 104 Cummings, C. E. 72 Cummings, .T. H. 229 Cummings Ranch 229 clay 229 tests of 349 Curran, .James 89 Curtis, T. S. 121 Cutter, George 185 clay on pronertv of 185 tests of 274 Cuvamaca Range 199, 200 Cyanite - -- 19, 29 Imperial "Valley, deposit of 86 use of 121 D Davenport 222 Davies, J. I.,. 111 Davidson, Nathan 100 Davidson Brick Company 100 clav. tests of 340 Death Valley S7 clay, tests of 316 Decoto, plant at 41 Deformation point (see softening point). Dehesa, Cornish stone at 95 Del Norte County 76 clay resources 76 Dempsey, .1. F. 23.5 Demp.sey Ranch 235 c'ay, tests of 313 Density, apnarent 246 Deutschke Hill (see .lones Butte). Diablo Range 129, 191 Diamond Brick Company "''- Diasoore 20 clay, classification and use 254 'Diatex' 211 Diatomaceous earth 30 Dickey. N. A. 40 INDEX 307 I 'age Uiokoy, W. S. Clay Manufacturing Company 40 li>ne clays 58 tests of 281) Xiles clay, tests of 34:5 use of 39, 40 Plant at hivermore 40 Plant at Niles 40 iMlltiian. M. .1. 155 Dirty-white-burning clays, tests of 348-352 Dosch jiit (lone) 58 clay, tests of 302 similar clay, tests of 274 Douglas, K. A. 118 Douglas pit 17G Drain tile, clays suitable for 255 Drain tile, manufacture of, in California 2G Drier, Carrier 27, 107, 209 Dry transverse strength 240 Dry press 28 Dry-pressing 16 Drying, methods of 17 Drying of test pieces 239 Ducor 231, 232 Dumortierite, in Imperial County 86 Duncan Mills 226 Durant, Edward 215 Durbin Ranch 67 ■Durox' 121 IHirst Ranch 236 Dwyer, W. P. 188 Over's Brickyard 123 Karthenware, red, manufacture of, in California 30 East Belt (Mother Lode) 68 Echstine, Mrs. G. P. 132 clay deposit 132 Eckland, Mrs. C. 59 clay 59 tests of 299 Edgar kaolin (Florida), tests of 265 (.See also under Florida clays). Edwin clay, tests of 272 Eel River 79, 82 El Cajon Mountain 200 clay deposit 201 tests 259 El Centro 83, 86 Electrical accessories, manufacture of, in Calif()rnia 30, 40, 100 Electrical insulators, manufacture of, in California 30 Electrical Porcelain Works 40 Elk Valley 77 clay, tests of 326 Elsenius, C. A. 49 Elsinore 162 Elsinore Joint Property 181 El Sobrante property 181 El Toro 19, 140 clays, use of (see al.so under Hunter Ranch) 101 Emeryville (.see Oakland). Emijire China Company 30, 101 Emsco Clay Company 169 clays 171 tests of 272, 278, 323, 328 use of 95, 97, 101-103, 111, 118, 119, 123 Emsco Refractories Company 101 Enameling, metal, in California 30 English clays 28 tests of 257 use of 40, 45, 94, 95, 99, 100, 107, 109, 117, 123, 215,220 Eocene 18, 42, 45, 64, 139, 140, 161, 162, 200, 202, 217,230 Epperspn, Mrs. H. T. 38 Escondido 199, 202 clay, tests of 348 Etna Mills 224 Eureka 79, 80, 81 Eureka Brick and Tile Company 80, 81 Eureka clavs, tests of 326, 336, 342 Exeter 232 368 INDEX F Page Face brick, clays suitable fur 253—256 manufacture uf, in California 2(j Face brick clay, detinition of 15 Fairbanks, H. W. 84, 140, 199, 200,212 Fairbanks, R. J. 88 clay deposit 88 Fancher pit (lone) 58 clays, tests of 280 Farr Siding 203 Faulstick Brothers 213 Fawcett, W. R. 109 Feather River (see under various counties). Feldspar 19 Arizona 28 San Diego County 201 use of 28, 30, 40, 45, 46, 94, 95, 100, 101, 109, 117, 123, 215, 220 Fernando formation 234 Ferrario, B. F. 73 Field, Thomas, Ranch 131 clay from 131 Field tests 237 Field work 12 Fillmore 233 Findley, Stuart 97 Fineness test 241 Fireclay, definition of 15 Fireplace tile, manufacture of, in California 28 Firing, methods of 17 Firing shrinkage 245 Firing treatment (in tests) 242 Fish Mountain 84 Fisk, H. G. 243 kiln 243 Flint fireclay 141 tests of 238, 282 Floor tile, clay suitable for 255 manufacture of, in California 28 Flores, Ramon 144 Florida clay, tests of 257, 265 use of 28, 30, 40, 94, 95, 101, 109, 117 Flournoy 231 Flower pots, clays suitable for 255, 256 manufacture of 98 Flue lining, manufacture of, in California 28 Forestville 227 Forget, A. J. 85 Fort Jones 224 Fortuna 80 Foster, A. J. 188 Franciscan formation 38, 71, 76, 79, 91, 124, 125, 126, 127, 129, 130, 132, 191, 207, 212, 215, 217, 219, 226, 229 Freight rates 21 Alberhill to Los Angeles 93 Freshwater Slough clay 80 tests of 342 Fresno 78 Fresno County 77 clay resources 77 Full Moon clay 85 Furnace (see under kiln). oxy-acetylene 246 Fusion point (see softening point). G Gabino Caiion 145 Gage pit (lone) 52 clay, tests of 273 Gamble, H. M. 65 Canister, deposit of 194 use of 97 Garber, H. 141 Garber Brick and Tile Company 141 Garden City Pottery Company 219 Garden Pottery, manufacture of, in California 27 Garden Ranch 67 Gardner, Harvey 174 'Gasco' brick 209 Gavilan Range 129, 130, 191 Gaylord, Ed. 159 Gazelle 224 Georgia clay, use of 46 CJerlack Brick Company 76 INDEX 36!) Page German fireclay, tests of 297 use of 97 Oil)l)Kite 20 Oilroy 219, 220 Gilrov Brick and Tile Company 220 Gin.nx, R. C. 42, 221 GlarUling, A. L. 151 Glacldinp, Charles 152 Gladding. MoBean and Company 101, 141, 151, 171, 195, 202 Alberhill clays 171 tests of 91, 265, 272, 279, 289, 290, 298, 300, 311, 312, 323, 324 Alberhill plant 173 Bryman clay deposit 195 tests of 314 Cardiff clay deposit 202 tests of 322 clay, use of, fmm Durst Ranch 23fi from Oroville 64 from Titus deposit 90 Klsinore Joint Property 181 Goat Ranch clays 141 tests of 282, 330, 343 Inyo County clay 88 Lincoln clavs _ 152 tests of 299, 304, 325 Lincoln plant 151, 153 Los Angeles plant 101 Santa Monica plant 102 clay, tests of 341 Temescal Tract 173 Tropico plant 102 Glass pots, clay suitable for 254 Glass sand 20 Glazing 17 Glenbrook 91 Glendale 102 Glen Ellen 227 Glen wood 222 Glenn County 79 Globe Tile and Porcelain Works 103 Goat Ranch 19, 141 clay, tests of 282, 330, 343 Golden Gate Sandstone Brick Company 76 Goldman, M. 128 Goodner volumeter 239 Goodyear. W. A. 199 Goodyear Station 225 Gorda 1^0 Gorge, clav near 159 Goss. H. F. 189 Gotham. T. B. , 215 Grass Valley 135 Gray.son ??9 Greenbrae 126 Green view 2?4 nrejre. J. N. 223 Griffith. A. "W. 142 r;rimp<^. H H. 67 Grog, function of If! Grog pit. near Tone 61 nros-Aimerode fireclays 19, 200, 202 GuadaUm«» 217 Guerneville 2^6 Gwin Mine '^8 Gypsum 141 H TT .Sr H Tile Companv 103 Kaaker. C. M. 140 ■FTaErerman. Ord. 103 TTalieman. V. K 103 TTnmilton cl'^v deposit 90 Hammond W J. 229 TTnnoork. C P.. and Son 181 TTancock's Brick Tard l^^l Hanford 90, 91 Kanifv Lumber Company R2 TTarbor City 105 TTardnes« 248 Waropnd'^fr Mi"e (see Valley View Mine). Warrie. Edwo»-d. .Tr. . 203 Harrington pit (sre Em.sco Clay Company). 24—54979 :]10 INDEX Page Hart 193, 194, 190 clays, tests of 264 use of 117 Harvey, Fred 63 Harvey pit (lone) (see Yosemite Portland Cement Company). Hasty, T. \V. 78 Havner, H. A. 105 Haverstick, Wm. 59 clays, tests of 262, 263 Hayden Hill 92 Haves, H. (}. 232 Healdsburg 227 Heins Lake clay 132 Helisma clay 68 tests of 305 Hernandez 191, 192 Hicks, clay near 195 tests of 288 Hicks, ganister near 97, 194 Hidecker, G. C. 41 Hidecker Tile Company 41 clay, from Marin County 126 High-grade ceramic pi-oducts 21 Hill, H. C. 121 Hill, J. H. 12, 162, 165 Hill, J. M. 130 Hislop, J. W., L. J. and W. A. 72 Hoff, J. D. 174 clay property 174 Hog Mountain-Gopher Range 68 Hoist pit 178 Holland Sandstone Brick Company 76 Holliman, R. H. 195 Holliman and Murphy clay 195 tests of 349 Hollister 190, 191, 192 Hollow tile (or block), clays suitable for 255, 256 manufacture of, in California 26 plants --21 statistics 31 Holt and Gregg 223 Horner, E. H. 209 Hoskinson, J. P. 70 Houts, W. A. 69 Howeth, H. B. 119 Hoyt, W. S. 73, 74 Hudson Ranch clavs, tests of 315, 341 Hue 248 Humboldt Clav Manufacturing Company 80 Humboldt County 79 clay resources SO geology 1 79 Humboldt State Teachers College 80 Hungry Hollow 80 Hunter Ranch 19, 140 clay 140 tests of 260 use of 96, 101 Huntington Beach 143 I Idria 191 Illinois silica 28, 30 use of 45, 46, 215,241 Imi>erial County 83 clay resources 85 cyanite and dumortierite 86 geology 83 mineral resources 85 physiography 83 Independent Sewer Pipe Company 171 Inglewood 100 Insulators, electrical, manufacture of, in California 30 Insulators, thermal, manufacture of, in California 30 Inverness 124 Inyo County 87 clay resources 88 geology 87 lone — - 49- 63 clay use of 40, 41, 97, 117, 128. 209, 215, 216, 220 sand, use of 39-42, 46, 49, 72, 74, 75, 94, 183, 187, 221 use of in cements 51 INDEX ,S71 Page Iiin»' Fin- Hriek Company 60 sand 55, 61 tests of 280 lone formation 19, 50, 64. 67-69, 128, 146, 147, 183, 185, 223,230 Iris Pass 84 Irving, n. H. 13 Irving, F. M. 74 Isitt, R. P. 119 Italian Terra Cotta Company 103 J .lalanivich and Olsen 207 Janiiesen, J. J. 221 Jenkins, R. H. 80, 81 Jenny Lind 68 .lens deposit 132 Johanson, Gustav 187 Johnson, C. P. 103 Johnson, H. K. 188 Johnson, I. J. 223 Jolon 130 Jones Butte (lone) 53 clays, tests of 272, 302, 328 Jurassic 50, 79, 139, 215, 217, 229,234 (See also under Francisf-an formation.) K K & K Brick Company 104 K & M Pottery 104 Kales, F. A. 76 Kaolin, definition of 15 resources of, in California 20 'Kaospar' 95 Kartschoke, G. 220 Kartschoke Clay Products Company 220 Kaspe, A. H. 89 Keeler, F. E. 96 Keeler, R. B. 107 Keenan, J. F. 203,205 Kelch, Martin 229 Kelley, Thos. 94 Kelley Ranch clays 203 tests of 296, 322 Kelseyville 91 clay 92 tests of 336 Kennedy, J. J. 194, 195 Kennett 223 Kentucky clav 28 use of 46, 94, 95 Kern County 88 clay resources 89 Kern County Brick Company 89 Kieffer, S. B. 12, 51, 52, 63 Kildale, M. B. 81 Kiln, Calkins 39, 45 field 26 Haigh 40 Hoffman 42, 74, 105, 125, 208 round down-draft 26, 27, 29 test 24 2, 243 tunnel 28, 29, 30, 216 Harrop 96, 123 King, Elmer 89 King, J. B. 220 King Lumber Company 89 Kings County 90 clay resources 91 bibliography 91 Kitchenware, manufacture of, in California 30 Knemeyer, C. V 121 Kraft, C. H. and J. L. 41 Kraft Tile Company 41 Krause, F. C. 144 Kremer, Victor 99, 109, 201, 205 Kummer, George 205 L La Bolsa Tile Company 142 Laboratory tests 238 La Cal Tile Company 104 Lacv, Roy 116 Lacy, William 109, 203 372 INDEX Page I^adrillo 204 Lagomarsino, J. J. 122 Laguna Hills 139, 140 Laguna Mountain Range 199, 200 Laguna Seco Grant 131 Lagunitas 126 Lagunitas Development Company 126 Laizure, C. McK. 12, 13, 73, 74, 76, 79, 190, 225 LaJolla 200 Lake County 91 clav resources 91 Lakeside 201 Lanoha Plana 50. 68 Landis, Judge J. B. 159 Lane mottled iiit (lone) 57 Larsen, Gustav 100, 105, 174 Las Encinitas Ranch 202, 205 Lassen County ^ 91 clav resources 91 Lassen Peak 230 Laterite 53, 54 tests of 328 Lawson, A. C. 124 Lead pots, manufacture of 39 Leash, H. E. 41 Lignite (see under lone). Lincoln 146, 147, 151, 155, 159 clay, general properties of 147 use of 39-42, 46, 49, 60, 72, 74, 75, 94, 97-99, 103, 111, 117, 118, 153, 183, 187, 209, 219, 221 Lincoln Clay Products Company 158 clays 155 tests of 291, 298, 303, 336 Lincoln, Earl 117 Lincoln Heights 111 Linda Vista clay 205 tests of 322 Linderman and Decker Company 104 Lindgren. Waldemar 64, 135 Linton, Robert 109, 176,203 Livermore Firebrick Works (see W. S. Dickey Clay Products Company). Livermore Valley 38 Llanda 191 Logan, C. A. 12, 13, 50, 51, 61, 67,182 Lomita 104 Lompoc 217 Long Beach Brick Company 105 Loofbourrow, Dr. T. L. 80 clay 80 tests of 342 Los Angeles Brick Company 105 Alberhill property 174 clavs 175 plant 176 Chavez Caiion Yard 105 clays, tests of 278, 279, 281, 288, 289, 297, 298, 300, 315, 335 Mission Road yard 105 Seventh Street yard 107 Los Angeles County 21, 92 clay resources 17, 93 Los Angeles Pottery Company 90 Los Angeles Pressed Brick Company (lee Gladding, McBean and Company ; also Richmond Pressed Brick Company). Los Burros district 1-^0 Los Nietos 114 shale, use of 1 1 f* Los Olivos 217 Los Pefiasquitos Canyon 200 Lovelocks ^'^ Lund, Nelson E. ^^ Lund Brick Yard ^5 clay, tests of 325 M M & S Tile Company 41 clay, tests of 343 Madera 123 Madera County 123 clav resources 123 Maeden W. T. 192 Magnesia brick 21 ■Maenesium oxide ''21 Mahan, N. J. 219 Maillard Ranch 126 INDEX 373 Page Malibu Potteries 107 Malibu Kanch 9-^. 10( Maiiufactiiring Methods Ifj ill California plants 26 .Maiizanita Mine clay 136 tests of ■^4^ Marl)l geology 124 Mariposa formation ov, os Marsh, C. L. 133 Martin, M. A. l^f Martin Ranch (Carmel) 1^1 Marysville 23() Marysville Brick Company 23() Marysville Buttes 230 Massey, Crawford 95 Mastercraft Tile and Roofing Company J3 McBean, Atholl 101, 151 McCarthy, P. O. 203 McClathy. H. J. 189 McClintock, C. V. 114 McClintock, Earl 9° McClintock, Wm. 109 McKissick Cattle Company ol, 63 McKnight Fire Brick Company 232 McKnight pit I" -^ clays, tests of ^^^ McNear, K. B. and L. B. 124 McNear Brick Company 124 clay, tests of 329 McNear Point 124 Melvin, II. D. 220 Mendenhall, W. C. °4 Mendocino 126 Mendocino County 126 clay resources 12" Mendocino State Hospital 126, 127 Merced 127.128 clay near, use of ]^° Merced County 127 clay resources 127 bibliography 12-' Merced Falls 1'''' Mero, C. V. and F. A. 73 Merrill, Dr. F. J. H. 199 Merry Widow Mine 90 clay, tests of 349 Mesmer, A. J., and Joseph 118 Mesozoic 87, 200 Michigan Bar clays 185 tests of 273, 274 Middle Bar 50, 68 Mid Hills 195 Millbrae 215 Miller, K. A. 99 Miller's Oakland Art Pottery 41 Millett, M. J. 195 clay 195 tests of 288 Milton 68 Mining (sec also under descriptions of clay pits). methods in California 20 Minner, V. J. 13 Miocene 45, 73, 80, 105, 132, 161, 193, 200, 215, 217, 219, 222 Mission Brick Company 107 Mission China Company 109 Cardiff clay 201 Mitchell, W. C. 203 Modesto 229 Modulus of rupture 240 Mojave Desert (see Kern, Riverside and San Bernardino counties). Mokelumne Hill 68 Mokelunine River 182 Molding (see shaping). Montalvo 233 Montecito 218 Monte Rio 226 o74 INDEX Page Monterey County 129 clay resources 130 bibliography 132 geology 12!t Monterey formation 124, 139,140 Monterey Mission Tile Company 131 clay, tests of 327 Monterey Park 120 Moore, G. W. 142 Morris, H. T. 202 clay 202 tests of 348 Mother Lode 50, fi8 Mt. Diablo Pottery and Paving Brick Company 7fi Mount Diablo Range 229 Mount St. Helena 227 Mount Sam Quicksilver Mine 91 Mount Whitnev 87 Muddox, H. C. 1S6 Muddox Pottery 186 IVruengenberg. R. 218 Muengenberg and Whitiker 218 clays 218 tests of 338 Muir, "SVm. F. 42 Mulford, William 203 Mullite 29 manufacture of 121 Munsell, A. H. 248 Munsell color standards 250 vs. Ridgway standards 250 Muresque Tiles, Inc. 42 Murphy, D. 195 Murphy, E. W. 105 Musick, property 77 clay (No. 180), tests of 32fi Myers, A., clay 41 Myers, M. C. 104 N Nacimiento River 129, 130 Napa 132 Napa County 132 clay resources 132 bibliography 135 Napa Junction 132, 133 Napa Valley 132 National Brick Company 203 National City 203 Natoma Clay Company 185 clay, tests of 337 use of 41, fi4, 128, 221 Neocene 68, 135, 136 Nevada china clay, use of 19, 30, 101, 123 silica 28 Nevada City 135, 136 Nevada County 135 clay resources 135 bibliographv 139 New Almaden 219 New Idria mine 191 Newman 229 Newman Clay Company 63 (See also under Newman, May E., Estate.) Newman, May E., Estate 61 clays, tests of 329 sand, tests of 261, 290 Newsom, J. F. 222 New York Mountains 195 Nigger Hill clay, tests of 263 use of 39 Niles 40 clay 40 tests of 343 use of 39, 42 Xlles Valley 38 Xoniilastics 19 North Bloomfield Road clay 136 tests of 329 INDKX ;5T") O rage Oakdale 22!t Oakland, day, use of Vu"i^"l9 H plants in 3S», 41. 42, 45 Oak Run ^^^ OCarroll. H. J. 13 Oceanside *^^ Ockernian, K. H. ^* O'Connor Brothers Brickyard f^l Odin Mine }36 ODonnell, Dr. J. M. — -- 192 Ogilby ^Sf^'97i Qjai m, i-i^ Old Mission Portland Cement Company 1-J2 Old Mission Tile Company 203 Oleta 50 Olive l*!' 1** Olive Roofing Tile Company \j^f Olivenhain ■^"'5' -^"^ Ollas. manufacture of ^° O'Xeill, Jerome Ij^ O'Neill Ranch clay ^jy tests of f:?; Orange County !.-y' clay resources f^y' bibliography j^^ geology \-l^ Orange County Brick and Tile Company i^o Oi-i(.l{ '■' Oroville, clay deposits and plants near --; 64 clavs, tests of •^'^='' •'•'^ Orpin, Chas. *^ Ortman, F. B. '"J Orton standard cones, end points of ^^2 Osmont, V. C. MA, iib Ottawa sand (see Tllinois silica). Owens Brick Company (see California Brick and Tile Company). Oxnard ;^^ Oxy-acetylene furnace ^*" P Pacific Clav Products Company 109 ^""cll^ys^^^of ^ --::::::::::::::::::::::::::::::ii^:^i:-^:2^i:^^. 32^ Douglas pit \ll Hoist pit Yl McKnight pit ]Y Miscellaneous properties '"" Kelley Ranch clays - {"^ tests of ^^'°' ^f^ T.,incoln Heights plant ']* I.,os Nietos plant ''^ SUnison Avenue plant 'Jjj Wildomar property l^" Pabricr), plant at *' Pacific Art Tile Company (see C.laddin, McBean and Company). Pacific clay l"^ Pacific Minerals and Chemical Comnany »» (Hee also Oladdine, >TcB<-nn and Company.) Pacific Portland Cement Coinpanv (foot note) ^^ Pacific Sanitary Manufacturing Company (see Standard Sanitary Manufacturmg Company). Pacific Sewer Pipe Company (see Pacific Clay Products Company). Page, Charles IJ Pagliero, J. '^ Paicines clay '2i tests of "'J' Paine, R. E. \l Pajaro River {^" •Paiacio' tile „--:;7""oV";;; ,no Paleozoic 79. 84, 87. 161.193 I'alermo, brick yard near ^^ Palo Alto 21H Palo Cedro •^-'j Palo Verde Mountains ^^ Panama Pottery 1°^ Pardee, J. E. „%i Parmelee, C. \V. 241, 253, 254, 255.256 Parsons, 'w. E. 1;'^ Paso Robles 212 Patent Brick Company 1^^ Patterson 229 376 INDEX Page Paving brick 18 Clays suitable foi' 2ou Peardaie ia5, 138 i'encils, clays suitable for 2uu I'enn iMining Company, clay VO tests of 31G Pentz 64 People's Lumber Company 234 clay 234 tests of 338, 339 Petaluma 22 G, 227 Philadelphia Quartz Company uO, (i3 Philo, b\ A. ys Picacho Hills , 84 Pike, 11. D. 211 Pilot Knob 83 Pine Hill Mine 137 clays 137, 138 tests of 261, 315,316 Pine Mountain 233 Pinnacles 130, 191 Pioneer Brick Company 232 Pioneer Brick and Tile Company 78 •Pipe' clay 136 I'ismo 212, 213 Pit River 222 Placer County 146 clay resources 146 Lincoln district 147 miscellaneous deposits 158 Plants, clay-working, of California 21 (See also under company names.) Plasticity, nomenclature of 239 water of 239 Piatt's Premier Porcelain, Incorporated 220 Pleasanton, plant near 42 Pleistocene 18, 139, 200, 202 Pleyto 132 Pliocene 64, 91, 161, 215, 217, 219, 222, 234 Plumbing accessories, manufacture of, in California 30 Plymouth 50 Point Loma 200 Point Reyes 124 Point Richmond 74 Pomona 116, 117 Pomona Brick Company 116 Pomona Tile Manufacturing Company 117 Porcelain, clays suitable for 253, 254 Porcelain insulators 46 Porcelain plumbing accessories • 100 Pore water 240 Porosity, apparent 245 Port Costa 73 Port Costa Brick Company 73 clay, tests of 326 Porterville 232 clays, tests of 327 Pottery, clays suitable for 253, 254 Pottery clay, statistics 31 Poxon, G. J. 117 Poxon Pottery 117 Power, M. I. 97 Prado Tile Company 181 Pre-Cambrian 79, 84, 161, 193 Preston, W. A., property 81 Prices, clay 21 'Promenade' tile 102 Prouty-line Products Company (sec American Encaustic Tiling Company, Ltd.). Providence INIountains 195 Prussing, Henry 100, 105 I'yrometric cones, end points of 244 I'yrometric control of tests 243 Puente formation 105 Pullman, V. T. 120 Q 'Quarry' tile 101, 102 Quartz sand (see also under silica) 20 lone 51 Tesla 45 Quartzite 19 Quatenary__64, 76, 79, 80, 84, 85, 91, 92, 127, 161, 191. 193, 207, 213, 217, 219, 227, 231 Quincy Road clays, test.s of 325, 336 Quintet property ISO INDEX 377 R I'age Radiant stove backs 90 liuiK-ho Arroyo Seco {see Arroyo Seco Grant). Kaniho tU-l I'aso ._ 183 Uanoho de Santa Margarita (stc O'Neill Ranch). Jtatio, pore to .shrinkage water 240 Itaymond, P. • 219 Red Hluff 2;{1 Red-burning clays, tests of 321, 352 Reddick .Mine 130 Redding 222, 223 Redding Brick and Tile Company 223 Redding Grant 223 Redding Homestead ^_- 223 Reed, T. H. 120 Reed Tract 231 Reeves, \V. N. 94 References, general 13 Refractories, clays suitable for 253, 254, 255 manufacture of, in California 29 tests of 243 Remillard, C. 42, 221 Remillard Brick Company, Greenbrae property 120 Pleasanton plant 42 San Jose plant 221 Reordan, \V. C. 100, 106 Reseda 97 Retorts, zinc, clays suitable for 253, 254 Reutera, J. F. 107 Rice, J. W. 204 Rice, W. D. 221 Richard, K M. 13 Richards, R. L. 221 Richmond 1 72, 73, 76 Richmond Brick Company 76 Richmond Pressed Brick Company 74 clay, tests of 325 u.se of 39 Ridgeway, E. 41 Ridgway, Robert 248 Ridgway color standards 249 vs. Munsell standards 250 Riley, L. F. 65 Riverside 181 Riverside Brick Yard (see Sacramento Brick Company). Riverside County 161 clay resources 162 bibliography 182 geology 161 Roberts, F. H: 100 Roberts, John T. 13, 60, 147, 209 Robinson, W. H. 103 Robinson Ranch 140 Roffe, \Vm. 203 'Roman' brick 183 Roofing tile, clay suitable for 255 manufacture of, in California 27 Rosamond 89, 90 Rose Canyon 203, 204 Ro.ssi, Ernest 208 Royalty 21 Rupture, modulus of 240 Russ Building - 27, 152 Ru.ssian River 226, 227 Ryan, J. W. 45 Ryan, Wm. 45 Ryan Ranch clay 45 tests of 263 s S. p. Brick and Tile Company 232 S & S Tile Company 221 Sacramento 182, 186, 187, 188, 189 Sacramento Brick Company 188 Sacramento Clay Products Company (see Cannon and Company). Sacramento County 182 clay resources 183 bibliography 189 SacraTnento Navigation Company 188 Sacramento River (see under various counties). Sacramento Valley, clay deposits in 17 (See also under various counties.) Saggers, clays suitable for 253, 254, 255 378 INDEX Page St. Louis Fire Brick and Clay Company 118 Weiss clay, test of 227 Salinas Valley 12y Salmon Creek 226 Salton Sea 83 Salt Spring Vallej' 68 Samples, list of tests on field ^ 258 methods of taking field 12 preparation of, in laboratory 238 weight of 238 San Andreas fault 124 San Benito 191 San Benito County 190 clay resources 192 bibliography 193 geology 190 San Benito River 190, 191, 192 San Bernardino County 193 clay resources 193 bibliography 198 Sand Hills 83 San Diego 203, 204, 206 San Diego County 198 clay resources 200 geology 199 San Diego Tile and Brick Company 203 clay, tests of 339 Sand-lime brick 144 San Emigdio Mountains 233 San Francisco Bay district 21 (See also under various counties.) clay deposits in 17 San Francisco County 206 San Gabriel Range 93 Sanitary ware, clays suitable for 253, 254, 255 manufacture of, in California 30 San Jacinto Range 199 San Joaquin Brick Company 208 San Joaquin County 207 clay resources 207 bibliography 212 San Joaquin Valley (see under various counties). clay deposits 17 San Jose 219, 220,221 San Jose Brick and Tile Company 221 San Jose Range 212 San Jose Tile Company 221 San Juan Bautista 191, 192 San Juan Capistrano 19, 14.'i San Ijorenzo River 222 San Luis Brick Works 213 San Luis Obispo 212, 213 San Luis Obispo County 212 clay resources 213 bibliography 215 San Mateo County 21.'i clay resources 215 bibliography 216 San Pablo 73, 76 San Pablo Bay 225 San Rafael 124 Santa Ana 139 Santa Ana Canyon . in Santa Ana Range 139, 140.141 Santa Ana River 139 Santa Barbara 217,218 clav, tests of 338 Santa Barbara County 217 clay resources 218 bibliography 219 geology and mineral resources 217 Santa Barbara National Forest 215 Santa Clara 219, 220 Santa Clara County 219 clav resources 219 Santa Clara River 233 Santa Cruz 222 Santa Cruz County 222 clay I't'soiu'ces 22'' bibliography 222 Siinta Crux Moimtains 220 Santa Cruz Portland Cement Company 222 Weiss clay, test of 227 INDEX 37!) I'agu Saiitii Lucia Mountains 129 SaiUu lAuiu liangf 212,213 SaiUa .MaiK'arita 212, 213 clay shale near 213 , le.sis of 327 Santa ^largarita, Ranoho de (see O'Neill Ranch). Santa Maria 217 Santa Maria River 217 Santa Monica 93, 94, 102, 107, 118, 119, 122 (Set- also under Los Angeles County.) Santa Monica Crick Conipany 118 clay 102 tests of 341 use of 97, 98, 101, 102, 104, 117, 118, 119, 122 Santa Monica Range 93 Santa Paula 233, 234 clay, tests of 339 Santa Rosa 226, 227 Santa Rosa Alountains 84 Santa Susana Range 93 Santa Ynez Mountains 233 Santa Ynez River 217 Santiago Creek 139 Saugus 233 Sbarl)ori, Louis 126 Schenimel, F. P. 221 Schrieber, Mr. 95 Schroeder, R. J. 117 Schroyer, C. R. 241, 256 Schutte, C. N. 13, 53, 147 Sears, W. A. 232 clay 232 tests of 282. 314,316 Seaside 131 Sebastopol 226, 227 Sewer pii)e, clays suital>le for 255 manufacture of, in California 26 Shade 249 Shakers, salt and pepper 38 Shale, common, in California 17 Shaping, of clay ware 16 of test pieces 239 Shasta County 222 clay deposits 223 Shepard pit (lone) 54 sand, tests of : 261 Shields, H. W. 232 Shoshone 88 Shrinkage, drying 240 firing 245 Shrinkage, water 239 Sierra Nevada (see under various counties). 'Sierra' roofing tile 128 Silica (see also under quartz and Illinois) 19, 28 use of 40, 94, 95, 100, 101, 109, 117, 123, 209, 215, 220 Silica brick 29 Silica (quartz), San Diego County 201 Simons. H.D. 104 Simons, H. W., J. V. and R. G. 120 Simons. W. R. 86, 119 Simons (town) 119 Simons Brick Company 119 Boyle plant 119 El Centro plant 86 Santa Monica plant 119 clay used in 102 Simons plant 119 Siskiyou County 224 clay resources 224 bibliography 224 Sizing, methods of 241 test, Natonia clay 338 Skee. Geo. 121 Skyland 220 Slip clay, definition of 15 Smart sville 235 Smith, K. M. 101 Smith, G. L. 41 Smith, Mrs. Mary Y. 90 Smith, S. W. 74 Smith River 76 Snow Ranch 67 Soda Bay 91 Softening point 246 380 INDEX Page Soft-mud .shaping 16 Solano County 225 clay resources 225 bibliography 225 Solon, A. I.. 221 Sonoma County 225 clay resources 227 bibliography 228 geology 22C Sonntag Ranch clay 135, 138 tests of 313 Southern Pacific Company 223 Southgate __99, 101 Specific gravity, apparent 245 true 246 Stahlman, E. G., and H. F. 116 Stammer, H. M. 219 Standard Brick Company 120 Boyle Heights plant 120 Inglewood plant 120 Standard Sanitary Manufacturing Company 75 Pacific Enamel Works 76 Pacific Mine (Hart) 196 clays, tests of 264 Pacific Pottery 75 Stanford University 12, 252, 257 Stanislaus County 228 clay resources 229 bibliography 230 Starkweather, G. A. 52, 53, 54, 56, 63 Statistics 31 Steiger Brick and Tile Company 225 Steiger Terra Cotta and Pottery Works 215 Stevenson Engineering Company 252 Stiff-mud shaping 16 Stine, I. F. 208 Stockton 208, 209 'Stockton' brick 209 Stockton Brick and Tile Company 208 Stockton Fire Brick Company 30, 209 Jones Butte clay (c. v.) 52 Stockton plant 209 Stoneware, clays suitable for 253, 254,255 manufacture of, in California 30 Strength, bonding 241 dry transverse 240 Strong's Station Clay 81 tests of 342 Structure 248 Sulphur Bank 91 Sunset Brick Company 123 Super-refractories 121 Superstition Mountain 83, 84 Sur River 129 Surf 217 Susanville 92 Sutter County 230 clay resources 230 bibliography 230 Sutter Creek, geology 50 Svendsen, C. V. 117 Sweet, John 138 clay deposit 138 T Table Mountain 64 Table Mountain Clay Products Company 65 clay, tests of 304 Tableware, manufacture of, in California 30 Talc 19, 28 Talc schist, deposit of 194 Talmage 126, 127 Tank Siding, clay at 222 Tara's Porcelain Laboratory 207 Taylor, F. M. 118, 136 Teale, W. R. 133 Technical Porcelain and China Ware Company 42 Tecopa 88 Tehama County 230 clay resources 231 bibliography 231 Tejon formation 42 Temescal Sixty property 181 Temescal Valley 18, 140, ]r,2 liNDEX 381 I'age Ttnu'scal Water Company 181 clay (No. 218) 181 tests of 329 Temperature control (see pyrometric control). Temperature, firing, range of 16 measurement of 244 Tennessee clays, use of 28,215 Terra cotta, clays suitable for 253, 254, 2r>r) , manufacture of, in California 2ti Terra Cotta Eighty property 181 Terra Cotta Plant Site property 181 Tertiary 38, 50, 72, 73, 79, 80, 84, 85, 87, 91, 92, 93, 126, 127, 130, 132, 135, 139, 158, IGl, 191, 193, 139, 200, 204, 207, 213, 217, 225, 227,229 Tesla 38, 207 clay deposits 42 clay, tests of 2fi3 Test pieces, drying of 239 molding of 239 Tests, field 237 laboratory 238 list of, on clay samples 258 Texas Mining Company 70 clays, tests of 263 Texture 248 Thebo, J. 85 Thermocouples, use of, in tests 243 Thermal insulators, manufacture of, in California 30 Thomas, C. R. 39 Thomas. F. J. l\ Thompson, J. D. 80, 81 Thompson Brick Company 81 clav, tests of 326 Tiffany, Jas. 109 Tile Shop, The 39 Tillotson, Clifford 97 Tint 249 Titus, H. E. 89 clay deposit °^ clay, tests of ^12 Tomales Bay 124 Tone (color) 249 Topatopa Mountain 233 Toro Canyon 218 Toro Canyon Brick and Tile Company 218 Toro Canyon Clay, tests of 338 Torrance J^^ Torrance Brick Company 120 Plant No. 1. 120 Plant No. 2 120 Towle, clay near 1^^ Tracy Brickyard (Eureka) |0 Transportation, methods and costs 20 Transverse strength, dry 240 Tremain, E. E. ion Tres Pinos 190 Trewhitt, ^V. D. ^^^ Trewhitt Brickyard 91 Triassic Ij^J Trinidad ^9 Tronico ^ '''• ' ' Tucker. W. B 12. 13, 82, 87, 92, 94 Tudor Art Tile Company 121 Tudor Potteries, Inc. (see Tudor Art Tile Company). Tulare County |^1 clay resources ^^l bibliography 23^ Turner, Wm. 1° Tuscan formation °' U Ukiah 126 Underwood, H. V. ^^^ Union Brick Company ^"* clav, tests of ^^" Union Hill ^ l^"! United Materials Coinpany ^* United States, clay products production in ^•> University of California 382 INDEX Page V Valencia Heiglits Khalt.' 232 tests of (No. 20ti> 3a< Vallejo 225 \'aIlejo Brick and Tile Company (see Steiger Brick and Tile Company). Valley Brick Company 189 Valley Ford 22ii Valley .Spring.s 68, 69, 70 clays, tests of 299, 337 use of 39, 128 Valley View Mine 159 clay 161 tests of 263, 328,350 Value (color) 249 Van Cleve, Albert 41 Vander Leek, Lawrence 226 Van Duzen River 81 Van Nuys 99, 104, 107 Van Vleck and Sons 185 clay on property of 185 tests of 273 Ventura 233, 234 clays, tests of 338, 339 Ventura County 233 clay resources 234 bibliography 234 geology 234 mineral resources 234 Ventura River 233 Vernalis 207 Vidal 181 clays, tests of 340 Vincent, M. L. 121 Vitrefrax Company, The 29, 121 Ogilby cyanite deposit 86, 87 O'Neill Ranch fireclay 145 tests of 259 Vitrified Product.-? Corporation 205 Cardiff clay 205 tests of 287, 288 Linda Vista clay 205 tests of 322 San Diego plant 206 Volcano 50 Volumeter 239 Volume measurement 239 W Wall, J. A. 45 Wall tile, manufacture of, in California 28 Wallace, D. W. and L. F. 221 Walnut Creek shale 73 tests of 342 use of 40 Walrich Pottery 45 Walters, C. J. 97 Walters, W. J. 89 Ward, Henry 68 Warfield 227 T\^ashington Iron Works 122 Water of plasticity 239 Water, pore 240 Water, ratio of pore to shrinkage 240 Water, .shrinkage 239 Waterford 229 Watson, H. L. 131 Watts, A. S. 241 Weatherhy Ranch clay 82 Webb, W. S 90 AVeed, C. H. 232 Weibling 143 Weiss, Henry 21.'> Weiss, J. H. 227 clay 227 tests of 262 use of 118 West Coast Calcimine Company 52 M''est Coast Porcelain IVIanufacturers 215 "West Coast Tile Company 95 Western Brick Company 122 clay, Santa Monica 102 Westinghouse Electric and Manufacturing Company 30, 45 Weston, A. M. 189 INDEX 383 ragf Weston, r'aul 208 West ViiHiiiia Ceological Survey 237 W li.atlaiid 23G \\ hiskjv Hill Mine iaec Valley View Mine). \\ liisl.r, C. .M. 45 Wliite-huining clays, tests of 257-276 \\ liiteware, clays suitable for 253, 254 Wliitiker, 10. H 218 WhitiiiK-Mfad Company 123 WiU-ox, Ralph 208 Wild, G. A. 122 Wildomar 180 Willow Creek 192 Willows 79 Wilson, Prof. Hewitt 13, 246, 262, 257, 262 Wilson, J. M. 181 I lay 181 tests of (No. 42-43) 340 Wilson. L. H. 97 Windsor 227 Winters 235 Wiro Mine (see Vitrified Products Corporation). Wolf 137, 138 Woodland 235 Woolenius Tiles 49 Worthington, R. L. 94 Wretman, X. E. 220 Wrights 220 Y Yankee Hill 66 Yaru pit (lone) 56 clays, tests of 302, 335 Yellow ware, clays suitable for 255 Y'olo County 234 clay resources 235 bibliography 235 Yosemite I'ortland Cement Company 63 Yost, A. D. 140 Yreka 224 Yuba County 235 clay resources 235 geology 235 Yuba Well 84 Z Zabri.skie 88 Zinc retorts, clays suitable for ; 253, 254, 255 O 54979 5-28 2M THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW .M * •« BOOKS REQUESTED BY ANOTHER BORROWER ARE SUBJECT TO RECALL AFTER ONE WEEK. RENEWED BOOKS ARE SUBJECT TO IMMEDIATE RECALL I » I t f{PP i t5?§ APR2 5REC'0 Pi StP2 RECEIVED PHyStCW-SCS-UBRARV NOV 2 C iSaS"!''' NOV 141994IEC1 RECCED PHYSICAL SCa DEC 2 9 1994 iVSICALSCS.UBRARy MAR 3 1 1997 :'fl ffECaVEo ' 5 m? ai Sciences Ubrajy na m LIBRARY, UNIVERSITY OF CALIFORNIA, DAVIS Book Slip-Series 458 92311 t.of nat.res Bulletin PHYSICAL PHYSICAL SCIENCES LIBRARY 1^24 C3 A3 no. 99 "rA/24 C3 A3 00^ of o= O: CD! CD! Oi WMIVSRSITY OF C/lLIFQBJOA 9AV1A 923// t ' i i