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Les diagrammes suivants illustrent la mdthode. errata to pelure, }n d D 32X 1 2 3 1 2 3 4 5 6 GEOLOGY OF THE YUKON GOLD DISTRICT, ALASKA, BY JOSIAH EDWARD SPTJRR; WITH AN INTRODUCTORY CHAPTER ON THE HISTORY AND CONDITION OF THE DISTRICT TO 1897, BY H^VROLX) BEA.CH CrOOUrMCH. 87 ] I llQ^c& CO NTH NTS. Pagp. Introduction li*l Chaiteh I.— History and condition of the Yukon gold district to 1897, by Harold B. Goodrich - 103 Early explorations... . - 103 Prospecting of Yukon district up to IHST ^ 107 Discovery of Fortymilo district and subsequent history to 1893. 115 Discovery of Birch Creek district and subseciuent history to 1897 118 Mission Creek -- 119 MynookCreck 120 Condition of Fortymile district 121 Condition of Bircli Creek district 121 Proposed hydraulicking 122 The Upper Yukon 123 Klondike district 123 Difficulties of development 125 Qovennncnt - - 127 Miners' meeting 137 Mining laws 128 Population 129 Production . 130 Table of production (Alaska and Northwest Territory) 132 Table of production (British Columbia) 133 Chai'TEH II.— The geological column . . 134 The basal granite. - 134 Microscopic descrii)tion. . - 135 Age of the Fortymile granite. 137 Extent of the gi-anite area 139 Correlation - 140 The Birch Creek series - 140 General characteristics . . 140 Composition of rocks 140 Correspondence of schistosity and stratification 140 Quartz veins 141 Summary 141 Distribution of Birch Creek schist 142 Thickness of the Birch Creek series 143 Microscopic study of Birch Creek rocks 144 The Fortymile series 145 General description ." 145 Dikes.. 140 Quartz veins 147 Schistosity. .. .. 148 Folding and faulting 148 Joints 150 "«r 90 CONTENTS. CUAPTER II. — The geological column— Coutinned. Page, Tho Fortyinilc scrios — Continued. Composition of FortjTnilo rocks. ' IHO Marble. .. ISO Quartzito - - loO Q>]artz-mic,'i-sc'liist 151 Qiiiirtz-hornblende-sclii.st 151 Epidotic^ schist 151 (TarnetiferoUH schist - 152 Garnet-mnscovito-schist 153 (iraphitic schist 153 Cyanite-schist . l.'iS Schistose igneous rocks 153 Original natnre of Fortyniilo rocks 153 Distribution of Fortymilo series 153 Thickness of FortjTnilo rocks _ 154 Resume . . 155 The Rampart series _ 155 Preliminary statement _ 155 Distrilmtion and general description _ 156 Fortymile Creek, South Fork 156 Between Fortymile Creek and Mission Creek 156 Mission Creek 157 Betw oen Mission Creek and Circle City 158 On Birch Creek 159 Fort Hamlin to Mynook Creek 1.59 Mynook Creek 160 Between Mynook Creek and the Tanana _ . 160 Megascopic characteristics of the rocks of the Rampart series 101 Classification of the rocks of the Rampart series 161 Diabase loi Quartz-diabase _ . 163 Olivine-diabase 103 Quartz-olivine-diabase _ 103 Qabbroid olivine-diabase. 163 Serpentine-tuffs igg Diabasic tuffs 163 Indeterminable tuffs 103 Clay-slate 1(53 Carbonaceous slate _ 103 Impure sandstone 104 Impure limestone. 104 Fine-grained quartzite, or novaculite. 164 Jasperoid i(j4 Schistose rocks . _ jgg Dikes in the Rampart series iqq Folding igg Joints. .. j(j7 Shearzones jg7 Veins - - - 167 Age of tlio Rampart series jg7 Economic importance jgg Previous noto.s I i I 1 109 TheTahkandit series. jqq Preliminary .statement 1A9 CONTENTS. 91 I Chapter II.— Tho goological column— Cuntinucd. Psko. The Tahkandit sorips— Contimien. Distribution anil goneral iloscrii)tioti - - 109 On the Yukon alMvo Circle City 109 Below Mynook Creek 1*1 Near the Melozikakat River 17.3 Correlation ami nomenclature 173 Other areas niaiipeJ as Tahkandit rocks 174 The Missiou Creek series - 175 Preliminary statement - • • 175 Distribution and general description 175 Napoleon and Chicken creeks 175 JUcroscopic characters - 176 Below Fortymilo Creek - 170 Microscopic characters 177 Mission Creek and below. 178 Kandik River and vicinity 180 Correlation - l'?l Age of tho Mission Creek series 183 Definition of the Slission Creek series - 183 Corresponding strata i" other localities 183 The Kenai series - 184 Preliminary statement - 184 Distribution and general description 185 Below Mission Creek 185 Above Kandik River - 180 Coal Creek -- --- 180 Above Mynook Creek .-- - - 180 Above the Tanana 188 Below the Melozikakat . 189 Between the Koyukuk and the sea --.- 191 The Koyukuk River 191 Correlation and age 193 ThicknessB of the Kenai series 104 Report on a collection of fossil plants from the Yukon River, Alaska, obtained by Mr. J. E. Spurr and party during tho summer of 1896, byF. H. Knowlton 194 Description - - 194 Discussion of age of rocks as indicated by plants 195 The Nulato sandstones.. -- 190 The Twelvemile and Porcupine beds 190 Twelvemilo beds - - 196 Porcupine beds - 197 Correlation 198 The Palisades conglomerates - 199 The Yukon silts --- 200 YukonFlats 200 Fort Hamlin to Mynook Creek 200 Junction of Tanana and Yuko-> 200 Above Twin Mountains 208 BelowtheKoyuktik --. 209 Silts between Lake Lindeman and the Five Finger Rapids 210 Interior plateau region of British Columbia 218 Pelly River - 218 Teslin (Hootalinqua) River 210 92 CONTEXTS. C'HAPlEn II.— The geolofficiil coUiinn— ContiniKMl. V»S»- The Yiikon silts— Continued. Kowak chivs and gronnd-ico f (jrnmtion 219 Corrchition - - 210 Age of the Yukon silts 320 The anciont gravels 221 Ancient rolled gravels 231 Ancient gulch gravels - 222 Volcanic ash -' 223 Ci!.\ I'TKK III.— Igneous rocks 224 Basal granite - 284 Dike rocks 225 Dikes in the Fortymile district - - 225 Earlier schistose dikes 225 Quartz-diorite-schist ' 226 Diorite- or syenite-schist • - - - - 226 Diorito-porphyry-schist 226 Later nnsheared dikes - 227 Extremel}' basic rocks 227 Pyroxenite - - - 227 Hornblendite - --- 227 Pegiiiiititic hornblende-diallaite-biotite rock ... . . 338 Intermediate rocks 328 Porphyritic hornblende-syenite 338 Quartz-hornblende-diorite 328 Hornblende-granite. .... 328 Fine-grained hornblende-granite (porphyritic facies).. 328 Porjihyry 239 Quartz-diorite, or granodiorite 339 Acid rocks 339 (traniticaplite. 339 Peguiatoid aplite 339 Dioritic aplite .... 330 Ordinary aplite 330 Porphyritic aplite _ 330 Pegmatite 330 Quartz veins 331 Relation of different varieties 331 Relative age of Fortymile dikes 333 Relative abundance of different dike rocks 335 Dikes of Birch Creek district 335 Sheared granite or granitic schist . 335 Unsheared granite 235 Quartz-feldspar dikes 236 Aplite 236 Dikes on American Creek 236 Aplite 236 Mica-lamproi)hyre. . . 236 Relation of dikes to schistosity 237 Dikes on the Yukon below Fortymile Creek 237 Dikes in the Lower Ramparts _ _ . 237 Quartz-mica-diorite 238 Granite or granodiorite 238 Dioritic aplite 238 < i CONTEXTS. yO CllAiTEn in.— Ih'iicmis roclis— CiintiiiuiMl. "'■''' Dike rocks— CiiiitiuntMl. Or.loroi:.lik..ro,-k« ^^^ AiIiM.f (likes -■ - -^ V<)kaiii<; or etlnsivo rocks . . - *^° Paleozoic— Rampart series ( ilial lases) »oO Geiieral description ^ Conditions of formation ^J^ Structure and comjiosition of rocks ••- S-*" Nomenclature - ^^^ Tertiary basalts "■•* Junction of the Pelly and Lewes •- •■' Miles Canyon . _ ' [^ Occurrence - "' Struc'turo and composition ^"^^ Chicken and Napoleon creeks - "44 ( )ccnrrence - " Structure and cpnipoaition j 244 Koyukuk Mountain and below - - 244 At Koyukuk Moimtain - 244 Occurrence and description 244 Strui'ture and composition 245 Between Koyukuk Mountain and Andreaf ski 240 St. Micliael Island 246 Occurrence and general description. 248 247 Craters - - *" Strnctiire and composition of lava - 248 Porcupine River 248 White River - ■•" Pelly River ^*^ Resume of composition and structure of basalt 249 A«e of basalts - 240 CUAITKU IV.— Movements in the earth's crust 2.51 Sunuuary of geological records in the rocks 251 (Geological map- - - - ■ _ Division of rocks according to dynamic disturbances 2.^i4 History of rocks to the end of the Rampart series 255 Birch Creek and Forty mile series 255 Rampart series --- - -- ^^^'l History from Rampart series to end of Kenai series 2oT Tlie post- Kenai revolution - 2.)i) Neocene movements - -- '■ ' Mammoth Mountains - - 20i) Drainage system - - 201 Neocene elevation - 20v Period of elevation 20.3 Volcanic activity - 203 Minor folding - - ^"■^ Pleistocene movements - - - """ oft", Submergence - --«■- _ Terraces in the vicinity of the Lower Yukon 805 Terraces on islands in the sea - 200 Terraces on the Upper Yukon and neighboring regions of Brit- ish Columbia 26S ;i4 CONTKXT8. CiiAi'Tnt IV.— Mi)vemeiits in the oarth's cniHt— Continued. Pbko. Pk'i.stoc'cnt' niDVcniciitH— Clint inufil. .Subnic'iK<'i"'P — Ciintiniii'cl. Terraces on till' rorciipinc 2fiH HubnierKenco iniiiciiled by terraces 26!) Period of ilepression 2"" Absence cif .1,'laciation and rock decay 270 Recent eU'Vdt ion 270 l-;viilen(es of recent elevation in the interior 271 Evidences of recent elevation along the coast 272 St. Micliail 272 Unalaska 272 UnKa 272 Other localities 27.1 Conclusions as to recent elevation... 274 Recent warpings as shown by drainago jieculiarities, hy Haiold B. Goodrich -. 270 Alaskan drainage as»illnstrated by Fortymile Creek 270 General aspect of country 270 Activity of Fortymile Creek - . . 276 The ancient valley 276 The present valley due to ujilift 278 Rivers as measures of warping 278 The Yukon 279 Fortymile Creek 280 Mission { 'reek 281 Mynook and Hunter creeks _ a82 Birch Creek ^'83 Causes of asymmetry of streams 28.5 Theory of differential in.solation 285 Theory of terrestrial rotation 280 The eflfect of geologic .structure 287 The effect of tilting 287 Summary 28!) Ch.vptkb v.— Valuable metals in solid rocks 290 Quartz veins 290 Occurrence 290 Divisions in point of age 291 Metallic contents of older veins 292 Metal 1 'c CI intents of younger veins . . 298 Microscopic occurrence of gold 294 Mineralized shear zones _ 294 ( )ccurrences 295 Genesis of aiii-iferous ijuartz veins 297 Transitions between veins and igneous rocks 298 The origin of diflferences in igneous rocks 300 The process of difTerentiation or segregation 301 The chemical variations of dikes 302 Order of succes.sion of lavas 304 Nature of the segregation processes 30") The pn icesses of synthesis or mi.xing 307 Contact metamorphism 307 Modifications of wall rocks 307 Modifications of intrusive rocks 3O8 Atmospheric mixing 303 T^ CONTENTS. 96 CliAlTER v.— Valuable metals in solid rocks— Cnutinucd. Paw". Genesis of auriferous (innrt/. vi'ins— Continui'd. The plienoinena of segregation j"^'^ Contemporaneous increase of silica and water ... !i"U Contact phenomena of acid rocks 810 Crystallization of granite "11 Crystallization of pegmatite 81 1 OriKin of certain quartz veins 818 Source of gold in qnartz vein .- ■ . -. 818 Gold in igneous rocks - - '"3 Mineralogieal relations of pewmatites and quartz veins to iKiie- ous rocks in general ... -i^'-i Manner of concentration ''' gold -'l-l Manner of solution and ,;" oipitation of gold •114 Observed connection of gold-quart-' vein- with intrusive rocks. :tl5 Summary ''^'^ Cli.viTEH V'l. -Placer deposits -• 817 Gulch diggings - 81 1 Fortymile district 317 Discovery 817 Bed-rock geology - - 818 (Geological maps 318 Description of gulches -- ■-- 319 MillerCreek 8i0 Shape of valley - 330 Gravels 8-,n Sourceofgold ■-■ 833 Glacier Creek- - --■ 834 Shape of valley 834 Bed-rock - 335 Gravels 325 PokerCreek - 826 Shape of valley 327 Bed-rock 828 Gravels 828 Occurrence of gold 829 Davis Creek - - 830 ^ Shape of valley 330 Bed-rock 380 Gravels - 331 Sourceofgold 831 Chicken Creek 831 Bed-rock - 832 Gravels .-. 833 Franklin Gulch 332 Bed-rock - 333 Nature of valley. . - 833 Gravels - - 833 Napoleon Creek 33.) Shape of valley 335 Bed-rock _ 835 Gravels. 336 Mission Creek district 337 Geological map — 837 Description of gulches 338 I i :^! oc CONTENTS. CllAi'TKU VI.— Plnccr (lepiisits— tVmtiimed. Pane (tnlch diggings— Coiitimied. MissiiiH ( 'icuk district— Continued. Description of gulclies— Continupd. Mission ("reck ,._ _ ._ ;t;i8 Nature of viillpy 3;iS Bed-rocks. _ _ ;!;i8 ( )Ider gravels :i;i!) Younger gravels ;i3i) American Creek ;j39 Bed-rocks. . ., 339 (travels.. 340 Mammoth reniiiins . 341 Birch Creek district - 311 Discovery _ 341 General geology 34 1 Geological map .•!43 Descriptions of gulches. . . 313 Hog 'em or Dead wood Gulch 343 Valley ;!CJ Lake accumulations 343 Bed-r( icks ,'j4,'[ Gravels ._ 34;) Greeidioru Gulch 34,-) Independence Creek JU,") Valley ;).(,-, Gravels _ ;j4(j Mammoth Creek ;{40 Mastodon Creek ;j47 Bed-rocks ;j4g (Travels....... ;j4fj Miller Creek.. .'jio Tojiography __ jyg Gravels _ ij,-,() Porcupine Creek _ ;),-,() Harrison Creek ;i,-,| Bed-rocks _ ;j.-,o Shape of valley ;j,-|.i Gravels ;),-,o Source of placer gold... ;).-,;) Eagle Creek . ;j,-,^ Mynook Creek district jj,-,,-, Discov<>ry ■^-~ (xeneral geology .. .__ ijjg Descriptions of gulches ggg Litth^ Mynook Creek 355 V"ii«T ^....V " V''. am Bed-rocks _ ;j-,(j <-riiv<'U '^\.. 'im Hunter Creek 3-,^ Shape of valley 353 Bed-rocks (j^,).j Gravels y^jj.) CONTEXTS. 97 m Chapter VI. — Placer deposits— Continued. Gnlcli (liK.ijiiiLts — Cuntiinied. ( )tlu'r tjulcli iligfjiiifjs Kliiudiki- district _ Upper Yuk( 111 - Shi^vliii Creek The Kiiyukiik Bar diiiKiiiK'* Manner (if formation . Helation of liars tn j,'iilch diKSings ( iccurreiices (if fjold in liiirs. . . _ ._ _ Ancient and Inssil placers _ Klevated aiirilVidus gravels Fo.ssil placers _ - Xapiili (111 Creek _ TheKdVukuk _ Conclnsioii __ Metals iitlier than gold in placers Origin nf placer gdid of Yukon district _ Derivatiiiu of gdld from certain rock formations _ Distriliution (if rich gulches with reference to geological .slruc ture . . - Gulches in Birch Creek rocks. _ Gulches in Fortymile rocks Gulches in llanijiart rucks ._ _ Source of tlie detrital accumulations in gulches Manner of concentratio". of gold... Processes of mechanical concentration Possilile cheniical iiitiiieiice in concentration.. CiiAi'TF.u VII. —Coal in the iieighliorhood nf the gold belt. I )ccurrences Charaileriif cdals _ Economiit values .. CaAl'TKU VIII.— Summary and jiractical applications . . Summary of report... . ... .. _ Practical applications of geological principles. CllAPTKR IX.- Methods I if mining Bar diggings Cradlin.g . (iulch diggings Sluicing Burning and drifting 18 (JKOL, PT 3 7 I'ano. ar.o 359 !i60 HOO ;i(tO ;trtO ao3 8«;i :!l!4 •.m •Mir, mr, mr, JifM 3(!6 ;!iir ;mT 3li7 371 371 •.i7i 375 375 377 3S0 3«i) 381 Wi 38) 383 38li 380 3Hit 389 3!)0 :!ni il '( 11 LI' ST RATION'S. J Platf. XXXII. Map of Alaska, slinwitit; ninre traversed by Ttiitcd States (ieiilofiical Survey jiarty ill ISIM) _ _._ Hll XXXIII. BdwMer of Keiiai coiiLtloiiieriite upiir immtli of Tiinaiia . . iss XXXIV. Ontline ii;a]i of tlie Lower Yukon and vieiiiity 1110 XXXV. The Yiikoii Flats 200 XXXVI. End of Yukon Flats and lieirinniuK of Lower Ramparts ','Oi XXXVll. I )utline map of the Upper Yukon and vicinity 'JIO XXXVIII. (Tt'olofiicalmaiiof the Yukon f^old licit and ad.iacent rcfjions '.'V.' XXXIX. Data mail of the Yukon },'old l)elt and ad.iaccnt re^'ionv '-'">' Xli. Terraces alonj,' the Yukon in tlii' vicinity of the Hay i{i .'cr :.'lil XLI. Strait between St. Michael Island ar.d Whale Islaii' •-'TJ XLII. Face of niorainal knob ad.ioiniiif.^ strait shown in Plai. XLI TH XLIII. lieacli at llinhuk, Unalaska Island, showing niarini' ter- races _ - - '.'TO XLIV. Map of a portion of Fortymile Creek, sliowing relation of ancient and present valleys _ ','Ty XLV. Maj) of F64 32 iCl no EIGHTEENTH ANNUAL REPORT, PART III PL, XXXII -|0« -irfl t^ Moaifled from r i Coast Survey Chart T aeoordlng ^ to exploratlont • XT. S. Geological Survey Party In " charge of J. E. S;-.t— 1896 Bed dotted lines iaote routes followed Dashed lines dm:- areas shown on larger scale maps Scale 1897 ■■--i-. i! : I ^ . . ' i ikWm \ ^--^ ll 1 i J^it. ULlua fliENftCO I » -* GEOLOdY OF THE YFKOX (iOIJ) DI8TRI(!T, ALASKA. By J. E. rSPURR. TXTRO UrCTTOX. The Hold work on wliicli llic accoinpanyiiitr roport is hassinl wnsdono in the siiniiut'r of J8'.m; l)y a party consisting:;, hcsidcs tlic writer, of Messrs. H. H. (loodricii and <'. !•". Scliradcr, assistant j,'('oiof,nsts. Tills party left ■Wasliinfjfton at the end of May and rt-tnrnt'd abont the middle of October, and tlins was enal)led •<< spend nearly four inontlis in actual field work in Alaska ami ad.jactMit portions of the North- west Territory. The route pursued is show n on the i^cneral iiuiji of Alaska (IM. XXXII) which accompanies this repoi't. l-'roni .Iniu'au our way led ui> Lynn Canal and tlieny Messrs. (ioodrich and Schrader. The published nuqjs were prepared larj^ely, and In some cases wholly, from our lield sketches; aUli writer records his thanks to his I'rionds and coworkers, .Messrs. (ioodri<'li ami Selnader, to whose i)er.soiial support and cndiir- aiicc of physical discoiarorl and (lan{,'er a large part of the .success of the nndertakin.u' is due. « :i C II A PT KR I . IILSTORV AXl) COXDTTIOX OF TIIK YtnCOX <;(>M> DISTHHT TO 1H1»7. By II AUDI, n n. (toiihukii. EARLY EXPLORATIONS. Tt was the fur !raak (Yukon) Kivei'sonu' "xio miles. While this eonipany was spreadinj; eastward fioni the I'acifie and JJoring Sea, the Kiiiilisli, lepiesented by the N'oi't Invest Company and later liythe Hudson I iay Company, were simullaiM'ously itushiuij their trade westward. In 1Sl>1 tlio KortliwesI and Hudson liay companies fo (1 a union. They had posts on the .Mackenzie River, where their servants lived and carried on business over l.iHH) miles fi'om the nearest civilization, receiving;- in retni'U salaries hardly larire enoujih to buy the ordinary necessities of life. The hardshii)s of these pioneers were many, but they pushed onward in the face of all dillieulties, lookiufi for new tields where a lucrative fur trade could be carried on; and in this extension of tho fui- trade tho idea of another passajfe to the Pacilic was kept eon- stantly in mind. As early as 17Si; La I'eronse had, in behalf of tho French (ioverument, underlakon to solve the problem of a northeast passage to the Canadian hikes or Hudson May from the western shore of America: but after .sailinfj as far as Litua Hay he becanio convin It-asc of llic •'cuasl slrip" uf Alaska in faviir (if the lliidsun Ita.v ('(iiii|iaiiy. and all tlif furs uf the Slikiiio l{ivi'i' fniiiid llicir way In iiiarkct mhui' easily at tlic jinsl liiiilt at Ilio iiimitli of thai liver. Tor lliis |iri\ile^re A:.',iiiiii aiiiiiial rental was jtaicl by llie eomiiany. Ill ism Deaseaiiil Simpson. Iiavini: recently discovered tlic month of the I'olville Kiver ,' of the year an expeilition in chary:e of Uoliert C'aiiipliell stalled from l''oil llalkell.oii llu^ Llard, asceiide(| t In- stream, and discovereil and nanicil France's Lake. He further asceiideij Kin- laysoii Ki\er to the lalce of the saiiie naiiic, and from there crossed to the I'elly, which he nanied in honor of ii pivernor
CONDITION. lO.-) niulf to till- Viiknii l)y wiiy nl' I lie I'drciipiiif was iiMicli casiiT iiiid los iliiiiK*'''"'"^ ''"'" '''"' ''y "iiy III' thf l''iiiiifi's tn I'lPil Selkirk; iicriiril- iii;;lv. in l>^"iii iiiui l'"^'"'! Ilif |"imIs at KdiM Kraiu-i's aii the river, which they knewbylhe name of Kwikiiak. It seems that even before this lime trijis had been made by Kiissiaiis up the river lo Xowikakal and by the Kii;,disli down lo that point, but the men had never met, and the Yukon and Kwikpak were sujiixised to be distinct streams, the one entcrinjj Ihe .\r<'tic Ocean and the other entering i;eriii,u- Sea. In ISdii Ketchiiin and Lebarsic. of the Teleirraph Kxpe- dition, ascended fi'om St. .Michael as far as Fori Selkirk, and proved conclusively thai the Kwikpak and the Yukon were identical. Previoiisto the transfer, the Kussian-.\iiierican Conipan\ had occu- pied Iradinir posts on the river as far u)! as Niilato. haviiii;- enlered the Yukon country from the Kuskokwim. near the head of which Kol- makof had established the redoubt, but with the openinj: up of the T< -ritory that coini)any yielded in favor of the Americans, and seveial coi.. aiiK'S immediately entered the field. The Kurdish were aceiis- toi' d lo send men down to Nuklukayet every sprin};to j;atlier in thi' 1 It is i-.'iiiirtiMl tlint Mr. Hnrpcr. one ot the nldi'st i>ii.iieer.s trf the Yulii.ii. dieil ..I' .■..iismnpti'.ii. after liis retufii t.i .he T'nitert Stiites, in I)i nilier. isiir. ■',\ kii ami lis Kesourees. Biwton. 1^711. pii :.'Tii -J". I(i6 (iEOLOi.Y OF Tin: VIKON (idl.U DISTRICT, ALASKA t'liis lliiil liiiil Ih'ci llc<'tc(l (lliiiii,i;(lii' witil.T. Iiiil in lSl;^. w licii ilicy iiiailc llu'ii' usual amiual trip, tlicy foiiiid an Aincricaii •foinpaiiy, wliicli liad ascend. '(1 llic river lln' snninici- Ix'forc anil located tliere. The latter inl'onned tlieni that they cdidd no liiniicr jmrsne tlieir tiade niMin Arneriean soil. It had Ihmmi siispecled tliat Fort Vakoii was well within the Alaskan lioMndai'y. alihoni,di its loeation had lievei' been .iclually dc-terrnined : so in \^<'''.K wiien a eonipany of American capitalists liad t'ornied the project of trading on the Vnkon, it was thoii,i;liI best to deternuMe once t'oi' all whethei'any I'ln^iisli Conipanx hail the riuht to carry on trade at the month ol" the I'orcn- pine J{iver. To this end Cajit. Charles W. Havmond was detailed 1o make observations of latitude and lonuitude at tin' conllueni'c of the two rixcrs. 'I'lu' party ascended the rixer in a steamboat — Ihelirst tinn'tliat one hail Moated on tlie Vids. In report ini; 11 pini the resources of the country from observations made on this trip, ('ai)lain Ua.vmond i-oncludos that the itn|iortatn'e of the fur trade had been greatly exasiit'i'iilcd. As tar as mineral wealth is coiicerneil, he dismisses it wit h ;i siiii;le sentence. '" No valu- able niincr.il deposits in workable i|naidilies hii\e been found u|) to the present time." In this is shown the attitude which lh(> trading com- panies lijid maintained and the policy they had pursued in the devel- opment of the country. Their attetitiou had h.'cn directed <'ntir(dy to the fur trade, to the exclusion of all other resources. Xor was this attitude always a pas.sive one. The story is told ' that when l!arain)f was chief inanaiferof the liussiaii-Aiiieriean ('oni])aiiy. a Russian who had been exiilorinu' the iiiouidains ba<'k of Sitka found several pieces of rich (|Uartz. Jiaranof assa.\ed the speeinieiis. but told no one of the result, and (udered the tinder to do no more prospecting;'. The idea that the mountains of the coast of .\laska coniaiued mineral wealth had been sun'u'ested : but even ajiainst the re])i>ate(l eH'orts of th" Kinperor to have his realms invest iirated, the .■iji'ents of the coin- l)any interposed objeetioiis. their real reason probabl.v beiuff that an increase of |)opulation resultinji from a di.scovery of jjrecious nwlals Would have u'r(>all,v lessened their iirollts. I''inally. in IS."),"), an euLji- neer, I)arrehan,' was sent by the Kinperor toexamiiie the shores. For some reason this ollicer made no exa'ni nation of I'.araiiof Island, where ' Ri'|)t. Dii'iTtoi- v. S. Mint iiimn in'iKiiii'tiim nf pi'i'i'iciiis ini'tals in r. S. ihii'int,' Isst. p. lii. 2 TliiM namt' is a miupriDt foi- DoroHhiii. oi- l)nro--'r, in thi' rei)o)*t citt'd. llooliKlcll. lUSl'dRV AMI ( ONDITION. 1(17 fidlil w.'is .-iricrwiii.is luiui,". ill Is'iS, ami liis ntlii-f iii\ I'sti^ai imis lia\- iiii;- pfdvci! iiiisalisfaflorx'. Iii' made an iiiilav orahli' icpnrt. Wliilo tile Kiiirlisli I'liiiipany look no sik'Ii |Misili\c sianil as this, il lu'vcr (lid any prospect ini;- nor in any \vii,\ ciicoiirairfil oilicrs to do so. I'liil it was soon sccii tlial tlicrc were otlwr icsoiiii'cs JM'sidcs t'lirs. and a iii'W (dcinciit licnan to coiiii' into proiiiiiii'iii'i\ In I s.")7 llic Hudson l!ay Conipanv liail ri'cciN nl t'roiii its agents on tlir i-rascr ami 'riiotnpson rivers in liritisli (oininliia. or Xew ( aleclonia, :!nii ininees of irold wliieli liad lieeii collected almost eyelilsively liy the Indians, who were very jealous of the white Mien. 'I'lie i,'i)orl sent by (Jo\ iMiior Dolijflas caiiseil the greatest excitement amoiit;- the liordes of miners in California who had not recovered from the attack of ■"n-old fe\er" produced li.Nthe dis<-overy of 1S4S. As one writer lias said. ■•The third ureal Devil's Dance of the nations within the dcea!7f came the Cassiar. and later the discoxcry of irold ill the vicinity of Sitka The tide of jrold seekers was setlinu steadily tiiwai'd the nori li. and it is not siir|)risinij: that, havinj,' found irold alonir all tiiese mountain ranges, prospectors should licifin to think of the \ast unex|)lorcd interior. PROSPECTING OF YUKON DISTRICT UP TO 1887. Tlie llrst iiredictioii of the discovery of tiold in fhe interior of Alaska had been made by Mr. W. I'. I'.lake.' In isc,:! he visitiMl the Stikine Hiver. in what was then Hussiaii .\merica. .\t this lime, althoiiuh ])lacers were beinji' w-(jrked near the mouth of the Stikine and ).:ravel bai's were payinj; iis liijih iis xlii per ss, mivuihI scHRiim.ii.4, 'U'l'iifi'-s'irniiilo' n'nmil<»ui|i. cit. ji. ilitlmt thi' until Urniiul'.t l.vtlu' liuliuiwli itln Tiikouii vTiiliui Hivi'i'. furtlii'r imrtli. whh iimi'li iMiii'wr tlinn timt IhiiikI upon tlie stikiiif I(l8 GEOLOUV OK TlIK YUKON' GOI.IJ IHSTRKT, ALASKA. ^ iikciii (•(iiiiilry— wiis iiiiulc in a Icltcr of .Mr. II. II. .Mclntyrc lo tlio Si'cfctaryof llic riiitod Slalcs 'rrcasmy in isip'.t. Mv. \h-li\\y\v caino III ihc coiicliision, from the siniilarily in liCDlogifai slrnt'tnre of the .•^iciia Nevada .Monnlain.s of Califoiiiia ami Ihc Rocky ]\roniitaiii r'anj^csof .\iaslalil,\ iTi 1 lie \ ieinity of l''oi't .Selkirk. Iii-itish tecritoi'y. was i'(?ported to the \\'cste!ii I'nion 'ri'lcitraph H\|)cdition. Hut this ydld was not in quantitii's to wanant a •■ fush" to the locality.' .Miont this time Dr. W. II. Da II wrote:-' ■"(iold i)i small quatities is found in the sands of the Nukoii neai' I'ort Yukon." In ISi;7 Ketchum and l.eliarjic, memliersof t he Teleurapli Ivxpcdit ion. ascended the ^'llkon and found evidences of uold on the iijipcr river. The fin'Ciroinj;' were casual oliserval ions, however, and it was not until(4eoruc Holt's li'ip that sy.slemalic jirospeclinfj^for jjold was liej^un. The dale is somewhat variously jriven as 1S7l', IS7."), ' and. liy Dawson, JS78. It is certain that Holt made several trips. (Mi his lirst one lie crossed the (hilkoot Pass and descended the Lewes Kivei' as fai' as Lake ]\larsh: icturniim from lliis point by way of the Teslin (Iloota- lin(|ua '), Dease Lake, and the .siikine Jtiver to the <'oast, he liiouaiil back jrlowinjf accounts of ci- so jjold on the upper Lcwos. It is said that in 1874 he descended the Yukon as far as the one hundred and si.xtieth moridiau, aiul ci'ossc(l the water portajie which bei,nns a1 the Kussian .Mission to the Ivuskok wim.' Holt appears not to lia\c 1 ii entirely relialile. and many of his stories of adventure have been dis- credited, but. be tlnMlatcs ot' his Journeys correct and his tales true op not, he was the lirst prospector who reiiorte(l jrold from the Yukon. In IXS.") he was the au'cnt of the .Maska Commei-cial Company at Kiiilc Hi\('r. on Cook Inlet, when, Inuinj; incurred the enmity of one of the Indians, he was murdered.'' Soon after (Icorfie Holt's first tri|), in 1S7:!, Hariicr, who was Ilio a.u'eiit at Foi-t Selkirk, ami I''red Hart, at that time employed by the Alaska Commercial Company, but who has for a number of years been a successful mimr upon Fortyniile, wenton a i)rospoeting tour in the St(>wai't- and \Yhite Uiver countri<'s. They I'ouml line itold. but no }Iood prosiiects on \Yliii;' River, and absolutely nolhiiifi; on Stewart, which was th>' scene of h>t or excitement. Hart attributes their failure to discover jrold upon 1h(> latter stream to the fact that thov did not I TiavclH ill Alnsltn and im tho Yukon, Wliyiiipor, Lnmldii. 18(111, p. aw. '^ Alaska ami its Kosonrcfs. Lumlon. 1S7(). p. 477. ' Aldska Ciiast I'ilut, Ittfvl. p. U1»l. 'Till' I'liitcil stall's Biiard or to the south is fidly l.("iti feet lower. However, not willistandinj,' tlic p'eater rou^'hiiess ;eleete of the liudson I'.ay ( oiupaiiy. who start eelnK"- P H" "'"' '■I'*"'- Wlll'I-L'. - .\iin lii'iit li.'cil Suiv Caiiiiilii IssTxi". Vnl. Ill, Part I. I'^wi. p. IT!" H. ' Sonati' E.\. Ill"' Nil ""H. Forty lilt li ('"iiKross, tliinl si'iwiou. jillT. 110 (iEOI.oiiY OF THK YL'KON (iOI.D DISTRICT, ALASKA. In ScplciiilM'r. is7'.i, tlio Iiidiiiiis rciiiovcd nil llioir ulucctioiis ti) tlio while riicii ciitiTiiii: I heir (•ouiitry, "wiiiir t<> the ilii)l«niiali<' llilcrccs- sioii of Caplaiii IJcardsIco, who was llii'ii in fliarjrc of IIr' ({ovcrnniont vessel Jiniiisliiini, slatiimeil at Siika. Dnrin;: the winter a jtarty of nineteen orjrani/eil in Sitka nnder the hsKlershiji of Kdinlind liean, the same who wiili a party had landed at Taiya (l)yea') in .May, IsTs, and had lieeii prevented from iiroeeedinu' to the interior at that time. They were liirnished with an escort ami hole letters to he presentecl to the chief of the trilte, Klot/.-Kntcli liy name, whose father had been instrumental in the raiil upon Fort Selkirk in 1S,')J, and who him.self had recently irix en some iroulile to the (iovernmeni re|)resental ive.^ The party. ineieasiMl to the number ot' J."i, landed safely at Taiya. Tho Indians, rec(iu;ni/.inj; the authority and letters sent to them li,\' Captain iieard.slee, helped the jn'osjieetors by supplyini; packers, and on .liine 17, l.ssii. ih(. company had crossed tliedi\ide. The disco\-ei'y of was worked and yielded ^;) to ><■") per clay pel' man. \{. Steel, oiu' of the members of tho prospect- in}; i)arly. reported on tliiscicek >'L'.."iii |)er ay Company. Here the latter [ta It y separated ayain, some takiiij;' the northern branch to l'(dly Lalvcs, ami others iroiiiir ' <> P'ranees Lake, in the Cassiar country, where they fell in with se\eral other prospectors ami ])resuniably stayed for some tiiiu'.' |)i'. |)aws(iu's version is that they ascendecl the Tes-lin-too (Teslin, or llootalin(|ua), and prospeeteil its bars, ret urn ini; by the sanu' route.' In the same year at least one other pai'ty ci'ossed the Chilkoot Pass. In ISS| iiinr miners crossed thepassand prospected the l>iu: Salmon Hi\-er. aii CONIHTION. Ill III tlic followiiijr yt-iir, 1^?^-, an I'xcollciilly dP.'.-iiii/cil ..\|m .iii ion jUlriiii)ti'(l lo i)ros|)cct llif Yukon from tin- oiln-r end. In .Inne llif imrty, consist iui,' of 1.") prospt-ftoi's iiiulertlii' Icnlcrsiiiii of Kiiw.nii mimI KIT Sciiicniin, (liscovcrcrs of s,'ol(l at Tonihslonc Arizona, wml loSl. .Mi('lia("i,l)oiig!i1 tlii'stcanilioal \i ir /.'-/cAv /, ;in .il.ove Die nMiutlitlieyaresaidtohavetliscovereda '■ mineral I lelt." 'I'liat falitliey prosiie aho\ .• llie Iradini: post at Nuklukayet, where they found bars yieldiii.- ''lo a n wln'iva r;inircof liills known as the Lower Ramparts are aligned with the river's course."' They returned to wiii'er ipiarters at Nuklukayet. hut in the spring of jss:i started up the river again and fonml iilacers paying -slo to s];, at Howetka.' (The latter point I have been uinilde to identify. I During the sui'uner they returned to St. Michael, sold the Xi ir llnrhl. and reached San Francisco by the revenue steamer Curir'ni. Tlieii' con- clusion in regard to the country was that it wouhl lo'ver pay for nnning operations on account of the severity of the winter ami the shortness of the opi-n season, but, while dissatislied witii 'he opiiorluidt ios alTordcd for mining, the Schielllins must have been mueii rat died at proving to their own satisfaction, at least, their theory that there is a great •'mineral bell "' eiu-ireliiig tlie world from Cape Horn through Asia and the Vcw \Yorld. They had found this mineral belt at several i>oints along the Yukon. • Thistrii»is interesting mainly because, while all the former |),()s- peeliiig lours had been in Mritish territory, this was the tirsi report of the linding of gold in the rniled State> jiossessions. Further, the ereeks and rivers referred to were witli miners found gold b'lH miles east of the Copiier, or .Vtiia, River.' This is [irobably a refer- eiu-e 1o Scliielllin"s party, which coiisislecl of .ibotit that number. In the same year iminy miners crossed the ChilUoot I'ass. anM. p. :.1'. 'JOp. i-it., p. •.".'. "OiiMiiy Hi. ls!i;.l-;a\vanlS.-liii'minilii'cliitCaiiyn:ivini-.(ir.-i;..ii. .\Uli..unli liv Miinl.M.v.-i- li.-ilf ii inilliuii rlolhirs lint ..r Ills di.MMVi'i-ii's in Ariz..iiii. In- .li.'.l I'l lu.v.Tty. liiiviuu- v,,uiiii.l.-r.Ml \\U luuin'y ill Viiriinis niitiiiit; vi'lituros. < Ann. lifiit, Dir.i-tcii- I'. S. .Mint. lw<;i. p. 'M "Ann. Iteiit. ("111. Sui'v. Ciiniulu Issr.sx. p. l.'.ii B. 11 112 JKOLOOy OF Till'. MKON (iOl.D DISTRICT, ALASKA. Ill jss:! tlierc was sonic niiiiiiiy in river bars (in llif I.cwcs, but ri'iiorts arc very incajrcr. This was llic year Ilial Scliwaliia niaib' his I rip on a Miilitary reconnaissance, lie notes tlic iircscncb of j;ol(i in jilaccr deposits, lic^iinniiif,' al llie iiioutii of a river wliicli lie called the D'Abliadic. but wiii.'li is now known by the name Uiis; Salmon, and colli inninjiiilniosi lotlic nioulh of lhe}ircat Yukon. He says that "a panfnl of dirt taken with discretion from almost any bar or bank will, when washed, jrive .several colors."' At Von Wilczeks Valley, I'll miles south id' the I'elly Kivcr, colors were I'oiind in the hijih bank near the river.-' The author concluded Ihat most ot the yold came from the I'elly l{iver, because the bars at the iiiouth of that stream were a little I'iclu'r in placer {fold than othei's on the Yukon: also because reports of successful small niinin^' on the Pcdly, jirobably rcferrinji' to the party iiieiit ioiicd above, had been broujfht down to Fort Selkirk. .Vnionj; the 200 oi' niori' miners who crossed the pass in the s|)riii of the Cassiar ' dislricl. I .M.iMu .Maskn's Itrciit Rivi'r, p. 1!N1. •n.i.l.. 1.. -.ii:!. ■Ann. Hi'iit. Uirc.'tui- r. S. Mint. I.SS.1. |,. :m. ' Ala..ilm ('ua>,t I'iji.r. l!*.'':!. |>. u1»i. »t'u.<»ittrlsii curniiitinnof fli,' nani.' Kaskii. ii],iiU,.tl i,, tw.i ti-ib.'sot Iiuiiiins iulialiiliiiB Hiia region. uoonBicH.) HISTORY AND CONDITION. 113 Thoillstrict lii'siu Ihotlrainafjebiisiudf tin Liiinl and I )casc rivers, in IJritisli C'oliuiibia. Dcaso I^akc issitiiatcd at about tlic cfiitcr. ami iho area is also coiisidcrcd lo iuciiid.' liic Stikiiic Kivcr. Iti \:w tlio fur traders (irst discovered tlie Stikiiu* Itiver, whieli iiad not l)eeti reeopiizcd by Vancouver in 17n:). In IS.-U the Hudson i!ay Company sent out, a vessel with sup|)lies I'or a post at its mouth, l)ut wore pre- vented from eiitablishiny; the post by the Russians, who ovected Fort Dicmysiuson the spot now occupied by Fort Wraiifrell; linally, how- ever, in 1837, a compromise was arranged and the I'ort jjassed over to the possession of the English coni|iany with the lease of the "coast strip" of Alaska. Several times Fort Stikine, as the post, had been renamed, suffered attacks from the Thlinkit Indians, once narrowly escaping lic Cusniur distrkt from ISf.', to ncfiil ni'iirs. Y.'iir. Mining ])opu- liitioii. Proiliii'tion of Kold. $1, 000, 000 830,000 550, 474 490,830 519, 720 405, 200 297, 8.50 198,900 182,801) 119,000 101,01)0 50, (100 (13, 010 60, 485 43,325 23, 935 22. .575 IXM . ... 2.O00 S(l(| 1.500 ,1 1.300 L.-^oo •is:5 l.sTd 1ST7 1S7S 1879 18S0 I.SNI .. 18X3 18*i l.Oiii) 1S,8-I ... 1885 18Stl 1887 . 1888 1893 1*195 (I Ono-third ChinoHO. When llu' placi'i" deposits luul become (^xluuisted it was found impractical )le to work the auriferous n, gave an impetus to travel over the Chilkoot Pass, and dui-ing the year IS.si- there was some milling on thePellyand Tesliii rivers, and on the former one party, it is said, took out x7(H) by bar washinjf. "i'hei'e were sev- ei'al other encourafrinj;: reports by prosp(;otors and travelers in the interior that year. Amonj; them was that of .S. H. ."\[cLenei;an, who was detailed for duty in the exploration of the Kowak River in 1884.' lie says: "In rcLtanl to the e.xisteiicc of .trold in this region, there seems to be little donl)!. In almost every stream, large and small, we found the color of gold." He refers to the prosi)ecting of the Yukon, which had then but just lieguii, and, like Schiefflin, canie to the con-* elusion that mining could never be sm-cessfully carried on, although ' Cniliu ot thu United States Reveinu Steanior Contiii, 1)W4, \i. KIT. ir. :'i nOUKHK'M.] HISTORY AND CONDITION. 115 at till' sanu'timp ivlinitting that placer miiiinj,' iiiiKht Iw iiiadi- n-iiimi- erative if largt.' (l('i)(>sits <'((iil(l hv found. In l!SS.") the rusti to the interior continued. On Stewart Wiver live parties prospci'ted and \vorl men were not ivroilueinu inueh. On the other hanil, liie reporls from I'orlyniiie were very eneoiirai;- in;;. Oti the ocean trip ha<'k to Seattle several iiiiiiers lirou;:'il witli tiieni alwHil s;i(iii apieee. Two new ereeks Avi-re slniek in this anil the sneeeeding year. Aecoi'diiif;- to an estimate liy the yovernoi' ul' Alaska, based mi con- versation with miners who Iiad come oul and rejiorted jjrreat richness, the ])rodnct ol' the Nnkun district was siT.'i.OOt). We have taken the mint, estimate, showin,!,' double the oul pulof 18!MI, us bcinj;'thc r(> consei'vative ol' ihe Iwo. althoujrii Ihis, on the other hand, is pinbably too low. Certain it is that in Ihis yea i' y;oUl minin;,' in the interior, as well as on the coast, al Silvi.'r l!ow l)asin and 'rreadwell. r( ived a great impetus. Tlu' eveiil of Is^'.iJwas Ihe discovery of .Miller (reek byO.C. Millei', a noted prospoL'lor bi Ihe ^'nUon counlry. Il had 1 n prospecled a great deal lieforc, bnl had always been i;iven up bcc.iuse the ^ravid was so deep I hat the labor involved in striiipinu' iiuide it unixolilablc working. In the lirst year of actual work, however, one claim is said to have yielded '<:)(l,iMiii. In Ihe spi'ing of IS'.i'" many new claims were slaked, and it, is cslinialed IhatsniiuMi look out «bio.iMi(i. Since that time .Miller (reek has been the heaviest jiroducer of I lie i'"orlymile district, and, iinlil rccenlly, of .he whole Yukon. Its entire length lies in Urilisli jxissessions. About Ihe same lime (dacier Creek, which lies next to th(> nortli of Milk r Creek, also ill llrilish territory, was discovered. Its |iroduct was probably not great during that year, the same dilliculty of deep gravel obtaining there as upon the former. The total output of the Yukon placers for bSicJ sliows an increa.se of ><10,(Hii) over IS'.H. In the s])ring ol iS'.i:! Ihe re[)orteil I'ichness id' Ihe inlerior caused a rush of minens, over :>iin men being em|)loyed in Ihe I'ortyiiule dis- trict alone, and a result of this increase in poonl'ilion waslliat pros- pecting was more vigorously undertaken. Manyjiarties made long trijis of discovery, and among these was one in which were such men as O. C. .Miller, Langford, Sinclair, and .Myuook, all noted |)ioneers, who j)rospected the Koyiikiik Uiver for many hundred miles from its mouth and brought liaek favorable reports. An eslimale of Ihe output is given in the rejiort of Ihe Dii'cclor of the Mini, as follows f\). 1 is), all the gulches and ere(d I'.IS.OOO II Not workf'i. DISCOVERY OF BIRCH CREEK DISTRICT AND SUBSEQUENT HISTORY TO 1897 T)i tlic siiniiiuM'df 1803 Pitka .iiid Soitcscip, IJiissiiiii lialf-bi'ccds who li;i(l riiiMicily \v()ik('(l ill (111- (liyLciiies iies1eii, wjio oll'ereil tlie ico'^'hs then in tlie warelioiise to oiil lit ail who eare(l lo make a 1 rial in tlie new district. Kii,dily men i^' ik advantage of liis olTer and, iiroeeeding down Iho river, built .■abinsat 11 ])oiiit on tlie Yukon 12 miles above the preseut site of iiie loun, called tlio settlement Circle City, from ils pi'oxiinity to the Ar<'t^' t'lrcje, and wintered there. During lh(> ico jam in tiie breakin;,- iin il the river thai sprin.u; the ponded water overllovved its banks and swept away a few cabins: so, warned by this accidoiil. tlie inhabitants moved farther down the river to a little hi,gher grouiul and built the new town of Circle City in ils i)re.sent situathm at the head of tlu' \'iikoii I'"lals. In the early spring the pro.spei.'lors had ero.ssed the old Indian trail over ^Medicine Lake to the head of Hireh Creek, had discovered and staked claims on .Mastodon, Ilog'em, .Miller, Greenhorn, and Inde- pendence creeks. It was soon seen that Birch Creek was a paying district, and that there was room fora large number of miners; conse- (piently almost all of the newcomers went to the new camp; the hranches and gulches of liirch Creek were traveled by prospectors, and Circle City became the most important settlement in the interior. In tlie Fortymile district the best producer was .still INIiller Creek; Franklin Guleh and Xapul'eon Creek were making good yields; Glacier KA. OUUIlllll II.] IIISTOKY ANI> rONHITIiiN 119 EQUENT bi'cods wlio k, i'(']»n'ti'(l i' news was ininci's t(i to i'oti'iii\ (' iii'V to Itiiy itlMl hy llic tlieii ill tlie }\y (lislrict. • Idwii llic I he present i pi'oxiiniiy jiliii ill the I'llowed its eiiloiit. the lior ffroiiiid liim at llie ndiiin trail (voi'eii aiKJ , and Iiid(>- 8 a payina' ers; coiiso- canip; the rospeetors, le interior, llor Ci-eeic; d.s: GliU'ioi' _\(". Cri'ok was bidding fair to i-iiiia! Miller; (ioiil and liedroek <'reoi\s liad also l)een prospeetcii lint pronouneed uiisatisl'actory, and the liai'^ on the main ereelv and tile river, wliile not by any means worked mil. liad I'aiii'ii olT in proihietion. In the nieantinie the Koviikiik was bein;^ prospected to some exteiil, anil ><.!ii,iu)o worth of aold is said to have been taken out and shipped Irom Taiiana Hading I'ost.al the moiitli of the 'I'anana l{i\er. The toial aiiioiiiil i)rodneed l)y the \'iikon jilaeersiii ls;i( wasiloiiliie that of the year bel'ore. and was divided lietweeii the two lai^'er dis- tricts as follows: Forlyinile $4(Mi,0()0 Uireii Creek '••.i""" Total 40'.i.(M)0 With the iioUi from the placers was broujiht out >i-Uiii.:iii in silver. Ill IS'.).") ihe output had donble0 miles below Circle ( ity, was examined, and a few men look out some ijold from I'reacher Creek. The center of the niiniiif; po|)ulation had by this time been trans- ferred from Fortyniile to Ciivle City; for, as estimated by the stalis- tieian at San Francisco, the population of Fortymili' was 5. Population. Distrii-t. Fortyniile. .. Birch Creek.. Koynkuk . . . Beaver Creek Total .. Product. 120 (iEOLOUY OF THE YUKON GOLD DISTRICT, AI.ASKA. All .It Ikt placers in xViaska, outside of tli»^ Yukou, produced in 1895 ^(ilt.iiS'.),o4. MYXOOK CREEK. One i)f tho Intost (lov(>loi)iii"nts is .Myii()(»k Creek, s j called from its discoverer, Jolui Myiniok. It is situated iu the Lower liainparts, 00 tu7i» miles above the month of the Taiiana. Tts()rij,'inal Indian name is Klanai-kakal, meaiiiii}," •' creek suital)le for small boats," and so it apiMJirs on t!!(> older maps of the rejjion. Inasmuch, however, as the names In com,non use by tiie miners and traders of the country are certain to supersede liiose iriven bv the natives, wo have used tlie latter nomenclature in all cases. The c.ctk rises in the hiirh moun- tains I'oiininfj the Tanana divide, and Hows in a general northward direction. Four miles from its Junction with the Yukon comes in lliinti'i- t'rei'k, ;iO miles loiii;-, wliieh rises near the liead of .Alynook 'v'reei< proper, ami Hows liist north, then bends westward around tile lie.id of Little .Mynook, another branch of the main creek. Still another lar.i;e branch, about :.'() miles loiijj;, enters from the south- west, 10 miles above Little .^lynook. On the riiited States Coast and (T(>odetie Survey imip the name Wliymper River, jfiven by Schwatka to the stream ne.Kt north of Klanarkakat appears, 'i'lie native name is Vukiitchkakat, meanin}; " biji; shallow creek," but later it has m)uw to be known by the name of Mike Hess Creek, or Hess Kiver, in honc>r of a. pioiu-er miner, who that tlic wliilc man should lake possession. Tn ]8'.t.")-'.n') iiiiifh new jiroiiml was pi'ospi'ctt'd in the l,o\V(>r Hani- jiarts. Myiiook and othcl•^s, having oxaniincd tho lloss Kivcr coiiiitrv and tho Tanana waters, report, d fine fjold on all the streams that liead ill the Tanana hills, hut Utile coarse frold. ^> eonts per pan being about the best iirospeet. On the K(;yii;;uk there were several men who stayed on until the summer. Another party ol' three men started from Circle City in the late winter, crossed the mountains near the head of Crooked Creek, reaehed the Tanana :>ii(i miles frr)m its mouth, and haviiiir built boats, lloaleti down to the Yukon. Alon^' the way they prospected side si reams and irulclies, bill found nothinir miieli. CONIHTUIN MF FdKTYMU.K DISTIilCT. The eondilion of tlie Forlyniile district in the summer of IS'.Hi was no! so piod as formerly. Ii looks very much as if i( had seen lis best davs. and unless several new creeks are discovered it will lose its old posilion. Chicken Cicek, discovered in the siu-inir of ]X'.n'>. caused a sensation foratim-', bi.i in the end more men left Fortymile tlian came into it duriiiji' the summer. John :\Iuller"s biff strike uudoubt- edh served to retain claim owners on Miller Creek, but, on the whole, Ihe e\odiis to .\merican Creid.' and the liirch Creek diirixiiiL^s was verv iioiicealilc. On (ilacicr and (iohl creeks about H") men were workiiii:. 'I'Ik' rkiiif; a low stage of water is Ihe most favor- able, but, as has been said before, the bais are nearly worked out, very b'w yieldini;- over *S a day, whicli, at I lie iirev.Mliuii- prices, would entail a loss. In all tlicre are probalily :!•'> men at work on the bars. rOMHTTdN OK BIKCH CREEK DISTUICT. In the summer of ISlHi llie liirch Creek district. |)artly owing to tin' fact thai on ihe whole lower river considerable rain fell during Ihe spring iiid summer, was in a tlourishing eondilion, and formed a con- trast to that of Fin'tymilo. ^Nlost of Ihe gulches were running, miners were working on double shifts, night and day, and many huge iirolits were reported. On Maslodon Creek over :iOO miners were at work, many of them e.Kpecting lo winter in the gulch. Thiity-si.\ claims of 500 feet front were being w(isl:ii llYliUMl.ICKlNd. On Mammoth Creek little work has been done. A short distanee below the mouth of Mastodon, on the rii,dit-hand side, the pay has been followed under a h(>avy deplh of jfravel, I)ut the breadth of the valley lower down prevents its location. Bars hn\- he: cashed for Hold on the -ueanders of this creek, and ^4 to •< ■ ■ .'.de. With the slow method of rockiuir and the existins infj;!; iiriee of the necessities of life, tiiis return woul'. not be \, .'ilable, i)utit is thought that iiMieh of the frround now too jioor to work mijfhf jjive fro,id returns uitii the use of soni(Muetlu)d of wholesale strii)ping au'l wasli- inu'. S f ,:■> miners have jdanned to work this and othei' good trround which is supposed to exist uudei' the dee|> eoverinirof moss an several years before their sclieme can l)e put into I'peration, because at |)res- ent both of tlie gulches art- [)ayiiijj: well, and they will continue to do so foi' the ne\t live yeai's at least. About that time the placer claims will be worked out. and it is thouKlit that then owners will have no objection to any usa^i' of the water. Tlicre are several disad\antaji<'s whiidi may render this scheme im nacticable. First and foremost is tiie hiffli cost of all the necessary implements and materials. Au;aiii, it has been foun of the sfulches. One of the I'esults of the ineonsfancy of the water sup- ])ly would be the daniaginji- of the fhimes. for boxes that are full at one time and empty at aiiot tier soon ;;o to pieces i'l' snow is not deep, nor is thei'i' iiiucli winil, so that the daniaj,je >. >' ftingc.ui l".' disrejjarded; however, that by freezing would be eonsideralile. Two oflu'r factors, ire to be eonsidiu'ed — the head fall of fhestreai". and the jiossibiliiy of disiiosing of the t'liliiigs. To calculate the first exaotly requires an accurafe f ;)))ograpliic survey and a series of levels from OOODBKH.] HISTORY AND (.(INDrriON. 123 the ,-cs("rv()ir1(> tlic outlet. We have not made sudi a siirvfx . ,iii.l cur aii.Toi.l elevations nuist be taken merely as an aiiitroxiniatiun f. tlie truth. From them, however, we would say that there is available ;iii 800-foot fall in 8 nules on eith.'r Miller or Mastodon, or loo f,.ei tc tiie mile, taking as a starting pointthe jiiirliest |)osition in whieli a d.iin restrainin.u- any quantity or constaney of watereould be built. Sueii a head of water would fjive suffieieut i)ressiir<-. aniountiiif;. as it clors, to somethiu},' over 000 pounds per square ineh, for in hydrauliekinn in ('alif(U'nia often only 100 to 4.50 pounds per square inch arc usc.I. A^^ reu.-rds the disposition of tailin.irs, there isapparently no icason why they could not lie run olT into Crooked C're(di. 'I'his stream lias considerable volume and v^■lo(•ityat the mouth of .Mammolh, and fr..ni this point to its mouth there is an avenge grade of :J7 fe.M per mile, sntlieient to carry off an immense amount of refus(\ It has been erroneously stated in one of tiie late mint rejjorts that hvdraulickini; with small hose has been employed in several localities. At no district visited by us was there a hose in use, nor could we learn of there ever having been any. The miner's inii>lcMients are always the simplest, consisting generally of a hand gnld pan. spade, whiiisaw, anda.x. These, with his blankets, provisions, and cn(uigh money for a year ahead, constitute the stmi total of his cai)ital. In fact, it is a well-worn saying that .Mask.i. is 'M poor man's country," almost no cajjital having been invested up to this time; hut if this plaM slhiuld be successfully carried llirough, llie ai)iilicat ion of liydraulics to other i)ortionsof the country would give the industry of placei' nuuing greater i>ernuinence and stability. TFII". fl'I'KH VtKON. <;n the Upper Yukon and on Lewes itiver. t<"r.itory properly out of the scope of this report, the old rock i)iles and a few ruined cabins a' sli!l to be seen on the site oi the Cassiar Bar excitement, but all the bar workings are desei'ted, the gulch diggings lower down being more attract ive. At tin' nioiith of Stewart liiver a few miners were in camp prepara- tory to a trip 111) ili*^' ''i^'^'""- " '^ Ihought that Stewart Hiver has not licen given •< fair 'liance -ince the lir.st year i^\' the exeilcment. Ju.sl at the lim.Mvhen good gulches might have been rs away. It is kno,Mi thai for JOO m.;v:.from the mouth the bars contain quantities of gold, ami ftu' this reason it is the general oi)inion of the miners that more wystematic prospecting should be doiu' along both branches of this stream. It is very probable, indeed, that many i)arties will winter there this year for that puriHKse. Kl.dNIHKK I>1STKI('T. The latest e.Kcilement in the country rhai)s 100 population during the salmon .season, for. as il.s name sif^iiifies, it has lon^' been a. favorite tishin;; fTround for the Indians, hut until late years it ha.s not been nvaded liy the miners. Willi the annoinicemenl of jrold there was a .enuiiie stampede to the new reirion. so that, wiii'e in the winter of 18it()-'.»7, Fortymile was almost deserted, it is estimated that 3.")0 men spent the winter on the Klondike, in the s'ulclies, and at the new lown of Dawson, established on the banks of the ^'iikon at its mouth. Jlessrs. Harper and .losejih I.adiie. tiao!ian/a Creek ami Hows into t,)uartz Creek, which is described as being a very long branch of Indian Creek. At h^a.st 10 miles below Kettle.sons Fork, Phil Creek <'omes in from th<' east, and still farther down, perhaps 4 miles, the main Indian (reek is met with, and ."> miles upthis isCiiltus Creek. I!ut the more important parts of the di.sirict ai'c. at present, upon lionanza and Hunker creeks. Cpon the former thedi.scovery was made, and >il.O00was taken out in Angtist and Sep- tember, ISIk;. Since that time, according to 'ast inforiMution, 400 claims had been loeate Other districts ' "•"> Total 1-7'iO 12o I $460,000 ] l.").()00 I OOO.OOO I 10. 000 5. 01"! 10. 000 1,400,000 While iniu'li iiioro conservative than the former, this, too. is irreatly in excess of the figures given by the Director i>f the Tnited Stales M iiit , for several reasons. One is, that %I,-iO(J,(XK3 represents not only the i)roduct of Alaska proper, but the added output of Mritish ereeks; another is, that, while the figures given below are compiled from the returns of bullion which has found its way to market, our ligures e.\pre.ss the amount actually turned out. The estimate furnished by Charles G. Yale, statistician at San Fran- cisco, is as follows : Charh'i (i. Vale's I'ntimaie of Alaskan out the middle of ^Fay, and by the 1st of June, the flood season having passed, the miners are at work. Winter cones on again about the last of September; the grouml freezes, the crteksand rivers stop running, and underold methods very little work could bo done. At present, however, in ; great number (i OKOLOGY OF THE YUKON GOLD DISTRICT, ALASKA. l'ni>|iccl(MS have also found it navantat?eoii8 to make their search f(U' favorable localities at tlie time when the frozen ground ren- ders travelinf; through tlie swampy, moss-eovered eountry easier, and for !his reason, more and more every year, prospeeting is done in the winter. Tlio elainis are tlius loeated and the! miner is ready to lu'triii work with the; lirst spring thaw. Krosts are frequent during the summer, and it is slated that in tlie winter tlie temperature has often fallen as low as —70' V. in the vieinity of Fortymile. It is easily seen, therefore, that, in spite of the riehness of the soil, the Vukoii district can with ditliculty heeomoan imiwrtant vt ,etal)le- producing country. Root crops have l)ccn tried with encouraging results in many localities, especially at Fort Selkirk, where last year potatoes of a pound weight wens raised. A small garden near Cone Hill on Fortymile Ch-eek also produced a good crop of cabbages and turnii)s, and at missions on the lower river turnips of great size were seen. However, there is always an uncertainty in the crop. To insure it against freezing it must be blanlceted many nights during the year, and in this eountry the hi},di price of even the < omnuniest, cheajiest kind of drilling pn-cludes the protecting of areas large enough to i)roduee crops sullieient to sustain even tlii-j small popula- tion through the long winter. The introduction of beeves has been tried in carry- ing such great distani'es and in such dangerous seas, even the com- monest necessity of life sells at the point of delivery at a price that would seem ridiculously high in the States and which is maintained at the highest [loint by the almost entire absence of eoiniietition in trade. As a sliglit compensation the rale of wages is much higher than in any other jiart of llic continent, «l(i a day being llie general wages, and in some of the more remote gulches «Il' a day of ten hours. In winter the juice for labor is ijo to ijiS per day of six hours. Hut this comiieiisation is only [larlial, foi' often the delivery of provisions isd( layeil by some accident, and llie miners, entirely deiiendent upon the outside world 4.00(1 miles away, must either leave tlie coiiiilry or must slop working long enough to replcnisli their stock of jirovisioiis by hunting. The loss from thiscau.se is often api minors lia\(' Ix'Oii at llic poiiil nt' slai'valinii, and tlicro is liardly a winter wlicii they arc not put on rations so nian>' |ioiiii(ls of bacon and so niucii tlonr to the num. Tin? ainio.st entire liiek of division of lal)or is al.so detrinicntal to projrrcss. .\t ])roscnt a man innsl not only l)e ndncr, hut lioii.se- linildcr, carpenter, and cook. To a jjreat cxtenti this is iluo to the ab.seiice of invested capital, which has been allinled to above, but it is beint; remedied by the imniitj;ratiun of labi)rers attracted by the high wujjes of the country. (iOVKRN.MKNT. Many MIXKHS MKK.TINO. The 'miners' me(>iinj.' is the oidy fi:overnmont in the interior of Alaska, but it api>ears nearly to havcoutlived its nsefuliit'ss, and with the ffrowth of Ihi^ count i-y and the introduction of a class of noiipro- dnciiiii; adventurers, attraetoil by the hope of makinj; fortunes at tho expense of the producers, it is fast boconiiiifj; a mockery. The better class of miiuM's have already objected to having; disputes occurrinir in the ji;ulchcs settlcnl in town, for tho jfreater i)rei)onderaiice of the disreputable class in the latter makes it alnntst impossible to obtain Justice there. Again, v.''ile i)erfectly wtdl intentioned, the minei\s ar(> often in)t the ones l)est fitted to decide cases iini)artially. Tho j)owers of the miners' mcotinu; are threefold — letrislativc, .judi- cial, anil executive. \o provision is made for a gmcrning olliccr, the whole fabi'ic resting on the great American principle, "majority rules." I'nivorsal sulfrage is given, and all have an cipial vote. The method of proceilure is as follows: If a man has a gricvjiiicc. he jjosts a notice to that effect; and calls a meeting for a certain date. At the appointed time the miners of the locality assemlile, generally in the open air, i'.nd a moderator from their number is appointeut on a sledge ami started on his way. In somejiartsof the counti'y the additional punishment of whipping at, the post is inllicted. Stealing has Immmi remarkably infre(|ucnl. I'or Ihri'atening with wca|)oiis the punishment is the same. There have been no murders in the country, but for the offense death by hanging i.s the iHMialty provided. (Gambling is a legitimate ainuseineut, and has no i>lace iu the catahigue of luisdeiueanors. 128 GEOLOGY OF THE YUKON G01,D DISTKICT, ALASKA. MINIXi; LAWS. Tlio iiiitiiiif,' laws as establishctl l)y llu' iniiu'is are sliKlit'lj- different fri)ni tliosi" iif the United States or Canada; in fact, thoy dilTer for dilT.'reiit ^'iijclu's. (Jciiorally llie flaiiii is 500 feet for gulch diggings, fi 1 riinrock to rMurock, l)iit in some gulches that do not pay well enough with small diggings an clToH is being made to stake claims l,:i-'<> feet long. On the otherliand, creeks which arc becoming crowded are staked :ioO feet to the claim. No one man is allowed to stake more than oticM'laiiii in his own name, with the exception of the di.scoverer, who is allowed l.ooo feet instead of 500. If more than one miner made the discovery, still only the amount of an extra claim is given to the discovery <'laim. The oTilyolViccr in the republic of miners is the recorder (one in each gulch or creek), who is appointed by popular vote. He is wit hout executive power.s, his duties coii.si.sting in recording the names of claimantsand the locations of their claims, for which he receives a fee estalilished for the particular gulch in whi<'h he holds oflicc. The amouiii generally received is *l' for every claim registered, although in some localities it is as high 'isSS. Sales of claims are also recorded with this officer, who collects a fee therefor, but here his duties end, or, -ather, beyond this point they are not well deliiied. It has been maintained by some that he has the right to rel'use to record claims if, ill his .jiulgment, to record tlicm would work inju.stice to another claimant, while others say that the power of deciding the question of owner'ship between dilferent jiarties belongs entii'ely to the minors' nu'cting. In the latter case it is obviously the duty of the recordei' to iid'ormthe prospective victim of a claim-jumping scheme; neverthe- less, he must make a record of all notices of occupancy. The law proviiles that for the month of July the nuner must do "asse.ssuMMit work," as it is called, and failing this, the claim is once more thrown on the market. In case a miner is prevented from doing this work himself, his title may be held good by proxy. So it happens very often, when a nuui goes out of tlie country foi' the winter, that he hires somemanto takehis place (mthe claim during the assessment month. These are the placer laws as applied in the American territory. Those which are beginning to be enforced on the British side of the line and are crowding out the ones formulated by the miners are the regulations already in force in other parts of Caiuida and British Columbia. The laws governing quartz claims in all parts of the Ter- I'itory are the same as the (luartz-t.iining laws in the States. It will be seen that we have here a .society in the first stages of formation. Up to this tinu' th(> people have governed themselves ami have done so veiT well, but there will come a time, and it is not so far distant, when the need for better government will be felt. iiiKiDHlrll,] HISTOKY AM) CONDITION. 129 Y different ditTcr for I (ligj;iii!,'s, t pay well aim8l,32(» owded are take more liscoverer, liiitM' made veu to 1 he er (one in is wiliioiit names of eives a fee fl'-ee. The I, altiiouyh ioroeorded luties end, [t lias been ord claims to another liiestion of lie miners' recorder to ; neverthe- er must do [lim is once from doing it happens rinter, that assessment 1 territory, side of the miners are and British of the Ter- s. t stages of themselves nd it is not ill be felt. Canada lias iippre<'ial<'d this need, and has stationed a garrison at Fort C'lidaliy to maintain law and robal)ly very lar),'e, is sliipiicd abroad direct without ever lieiii}; deposited in any mint in tlie I'liited States. Fiirlherniorc, niiicli gold remains in Alaska for many years after its production. Taking all these facts into consideration, we think it conservative to ad. (100 9 2,000.00 14 11 ;< 7.5, 8,58, 200 1887.... a::,, 000 9 300.00 11 r C30.000. 1 30,000.00 ) f I 200 50 1888 8.-)0. 000 8 3, 000. 00 10 9 J- 40.000.00 I 35, 000. 00 1 * f I 100 1.50 1880.... 900,000 9 10,843.00 14 11 f 35, 000. 00 *■ 40,000.00 ^ { 1.50 135 IHiHI. Ttl2, M(\ 9 9,097.00 14 11 50, 000. 00 7 { 1.50 1.50 1801 ... 900, 000 10 10,343.00 14 11 100,000.00 11 { 200 1.50 180'>.... 1,000.000 9 10, 343. 00 14 11 110,000.00 11 f 1 225 175 180:t.... 1,010,100 9 10,800.00 14 11 ' 200,000.00 30 { 500 200 1894 ... 1,113, .wo 9 28, 783. 00 13 11 i 400,000.00 i 37 1 400 GOO 189").... 1.01.5,300 7 86,880.00 13 9 709,000.00 44 { 600 800 180(1. .- Total. CorVfd 2,014,203 4.5,708.72 800,000.00 SO ; 700 1,000 12,240,313 827, .500 13, 067, 813 320,491.03 d3,483, 000. 00 ' 1 827,500.00 1 1 i 1 1 i 3,310,500.00 1 35.. II II (I E. R. Siidmorp. hU, M. Diiwson. , , , ., , rill brai'keted tlKure.s the upper set refers to British territory; tliu lower to Alaska. (/ Total output from American territory only since 18NI. For the purpose of eoinpnrison we }?ivo the table of tlio production of Uritish Cohiinhia from 1S.58 to 18I»5, takeu from the AnuiJal Report of the Minister of Mines, 1895: ^KA. msTOHY AND (ONDITIOX. 133 Output T.v /,, /\,'i OP tof > uintx'i- lid of Yukon j production uUal Report 18.58... 18511... 1860... 1861... 18< 794, 252 1,965 404 735, 965 1,858 39(1 713, 738 2.902 246 903, 652 3. 147 287 694,709 2, 342 296 616,731 2.007 307 636. 79(i 1.929 830 56.8,419 1.343 423 439.811 1,199 3.58 399, 526 1,340 298 379, .535 1,247 3(W ! 464.. -.66 1,610 283 036. .545 2, 030 313 5.5.11.5,965 ■■■HP C U A V T K K T T . Tire (;kc>j.()(;u'AL <'oi.i'MN'. THE BASAL GRANITE. Tlic . ^lost rciek foniifUion louiid in ilio Yukon fiold dislricf, is graiiilo. Only in (lie Korlymilc district lias this rock been studit'd in any detail; for in Ili<' otlicr itold-niinini; districts which wore cjirc- fiilly examined it does nut appear to be exposed , and ui the rej^ions which were more hastily passed over there was not suHicient oppor- tunity to separate it clearly from other ^rnK-'o which occurs in the same areas, but which is clearly y()un,!>"r and of in granite, while others, such as the garnet, re[)resent const riiclive processes attendant upon the development of the schistose structure. Since the rock h.is thus evidently been subjected ii, great shearing and alteration, bring- ing about the formutiou of now minerals, if niav bi> called a schist; yet 134 t UBR.] TIIK IIASAI, (iRANIIE. 135 (lislrict. is •un stiulit'd wore oiU'c- tlu' rcirioiis icilt (»])[)< •!■- nws in llio origin, 'reek 1o tlio learly niid- niiles wide, nrsclii.stosei less altered yrilit! crys- u lenticular Iianges to a )s, (gnarly, I veins, are sehistose dionio.jdiie ilet'aced hy linerals are s .nieii, aro ortlioel'ise, allcKiirsely fiM t iiiieno- kaoiliii/.ed i: s attendant he rock has iIIdii, liring- isehist; yet ;i the jiranitie strneture is usually (luite uninislakable in tiie li"len spoken of as occupyin;? a lielt several miles wide nn ilie Miller Creek trail lietweeii Fortyniile ami Sixty- mile creeks. On Ixitli sides of this licit arc sciiists whicli ai'c in part micaceous or hoi-id)lcndic, and often pass into less common vaiiclics, but wliich are, in most eases, made up chiefly of (|uart/.; and study, bolh in the ticld and under the microscope, nuikes it clear that they a (■ altered ([uartzitcs. These (|uart/il(^-schists. as we may call them, arc identical in api)carance on both sides of tiu; j^ranitc licit. On the side toward Fortyniile t'reek tlicyare continuous from tln-i;ranite licit nearly to the main ereek, when they jiass into a formation wliicii is made uii very larjrely of marble; on the side toward S'xtymile (reek a narrower band has been examined which is made up entirely of ((uartzite-sehists. Throughout this whole cross-section from Forty- mile to Sixlymile t'reek the schistose .(tructure strikes nearly uni- forndy east and west. In passing from the (puirtzite-schist to the marble on Fortymilc (feck one observes that the two rocks are at first finely iutcrbernation of riuartzite and marble in small bands jrives the true beddiiif; of the series, esiiecially since this is often found in places where the forces prodiicin};; the schistosity have acted very little and can not have changed the original order. The niicro.scope, moreover, shows (luartzite passing into marble through all transitional stages, a I'ommon I'ock being a calcareous or (loloiiiiti(! qiiartzite in which are zones of calcite or dolomite inclosing ([uartz grains. This alternation of marlde and (iuartzit(\ giving \\w true attitude of the beds, conf Forks, it will bo soeu thai 111.' Mill.'r Crock trail is a crDss-sooti.iii, ciittiiij,' very noarly at ri;;hl aii;;l('s to the forinaf ions. From the attitude of the marbles and iiilerlM'dd.'d .iiu.rtzil.'s on ^foose Creek, it f.)llows that the quartzite- sfhists of Hi.' Kiich Creek formation underlie the nnirble beds of the Fortymile format i.m. It has also been sli.iwn that at the contact of these two fornmlions the actual attitude of the rock conforms to tlio schist. )se structure of the .luartzite, so that the schistose structure of the qnartzile represents at that jilace the true beddinj?. Between the Fortymile formation and the sheared jiranile zone the strike and dip of the schistose i)lanes in the quartzite remain the same, so that the frranit.' has th.' appearance of un.h'rlying the quartzit>^-sehists. On the south side of the !j;ranite, li.)\vever, the qnartzito-schists, while havin;;a p'lieral east-west strike, like that of tlie same f.irmation on the other sid.' of the K""">ili' belt, have a general dip to the south instead of to the north as b.-f.ire. This dip is comparatively flat, avera.iriiiir between HI" and -20". The east-west strike and the south- erly dip are practically uniform, excei)t wliere distuvl)ed by minor folds. If the schist. isily in the (|uartzile-schist on botli sides of tlu» jrranit.' belt is parall.d with the original ])lanes of sedimentation, as lias been shown lo be the case on Fortymile Creek where a test can be applied, Mien th.- northerly dip of the of those near Sixty mile Cii'ck in.licate an anticlinal fold. iii'sidi's till' -Miller Creek trail cross-s.'.'tion, another section across tlie jfcncral strike of 'he beds is afford. 'd iilonj; the Soiilli Fork of Forlyiiiilc Creek, between its, junction with the North l'^>rk, and thv count ryaroun.l F'ranklin Gulch and Chicken ('reek. This section is, howev.'r, not so satisfactory, for there is a ;j;r.'at am. )iinti of intrusive rocks, which have distorted and altered the sedimentary schists so that the {fciieral structuri' is often tl.iubtfiil, and even the nature .»f the si'liistos(> ro.'k is notr always clear. Xe;ir tlie Forks, however, the frcn.'ial dip .if 'he beds, as b.'fore, seems to b.' to the north. Tlu'se bc.ls are the ii,,irbl.'S ami .(Uartzites of the Fortymile formation. Soiitli.if the Folks there is a broad b.dt in which the inti'Usive rocks are so abundant ami cause such .list urban. ■(> and alteration that tlie slrucliire of 111.' .s.'dimeiitai'y rocks is uncertain. On the s.iuth side of this bi'll are marbles with inler.'alatcd siliceous schists, which liave as before, a frcneral east-wesi strike, but. a uniform .southerly dip, so that they pass down under youiifrer ro.-ks. Tlu'sc Iw.i cross-se.'ti.ins establish the existence of an anticlinal fold rtith an east-west axis parallel to I''ortymile Creek between Moose Cre.k and llii' Forks. The section on lhi> South Fork c.impared with that of Miller Creek trail shows a closing oi the fold toward the west, i^^- CA. Till-; HASAI< (iRAXriE. 137 I'll as hav- 1 marbles ill 1)0 SOPH nearly at arhles and quartzite- kmIs (if the contaci of •nis to tlie met u re of (tween tlie ko and dip ■<() that the liisls. On ists, while mat ion on the south lively flat, the soiilh- Ity minor des of the ntation, as a test ean sts on the ■ Sixtyuiile t ion across h Fork of ■k, and tht> seetlon is, f intrusive schists so ' )iatiir(> of )\vevcr, the Ih. 'I'iiese formation, isive rocks m that th(> south side vliich have herly diit, antieliinil cen .Moose pared with I the west, for liere the distance between corresponding format ions across t tu' fi dd is niueli less than in the other cross-section, as is shown on the map, PI. XL\'II, p. :!1.S. In this section the (plartzite appears to lie contined to a narrow zone and to form the summit of the anticline, no sheared granite belt having be(>n observed, although the many ilikcs ami the coi.seiiuent metamorphism make tl;c matter doubtful witliout more St udy. As far as can be seen, however, the contact o granite withtlie sedi- mentary schists roughly correspondsin ont''/ie with tli(> strike of ine.se sell ists and with tli(> contact of tho(piartzite-.schists with the overlying marli'es of the Fortymile formation. This granite therefore has the fonu .if outcrop characteristic of a rock lyingstratigrapliically lieiieath the sedimentary schists. On the .Miller Creek trail no intrusive phe- nomena were noted near the contact of granite with other rocks, but oi. ac<'ount of the schistoslty of Ixith format ions such iiheuomena miglit eisily be ob.scured. The possibility still exists, therefore, that the granite may be intru- sive, having broken through the scilimcntai'v rocks in a massive body and dragged up the Itecls so iliat tliey lie on its flanks, dipjiing away ill all directions. Throughout the gold district there are largo quantities of granite which have cut through rocks in this fashion, as is abundantly proved by the contact i>lieiionieiia. At the same tiiii(>, these jilaiiily intrusive granites are m iliii.irily massivi' and have no schistose sti'iiclure, being, therefore, Liii-i- iliaiithe ili^i iirl)anc(> which brought about this structure MJiih- the granite lying along the axia of the Fortymile anticline iiarkedly scliistose and can not he rclerred to the sam(> jieriod. Anolhei' theoretifal consideration is in regard to the naliire of the rocks whii'li lie ..n ImiiIi sides of the sch >- tose graiiili' of Fortymile Creek. TIicm liisls, as has 1 n said, are beds of altered quartzite, and the plainly ib iriial grain^ .f which they are coiiiiio.sed are chiefly quart/.. In .some i use--, howe\ir, otlier materials are present; rounded grains of feldspar arc fouml. ln.ili orthoclasc and plagioclase, containing sometimes flakes of biotiie iind graiiisof e])idole; di'trital grains of zircon, a|)at it e, and iii,i_'netii. have also been observed. 'JMiesi' minerals must necessarily hi \e come from the deiiiidat loll of .some older rock, and their nal un> suggests deriv- ation from granite. It may therefore bi concluded that ilie I'orty- mile granite is older than the schisto.se .sedimeiilaries aid n I'lies them. KXTKXT 111' Till'. (iUANirK AKKA. As stated, this granite occurs along the axis of a fold whose trend corresponds in a general way with the sehistosity. This same east- west trend of schislosily is found nearly uniformly in the schists from Fortymile Crtck along the Yukon to near the junction of the I.ewes niid I'elly, and throughout this distance belt.s of granite alternato 138 GKOI.OGy OK THE YUKON' GOLD DISTRICT, ALASKA. with hells of schist (•orrcspomliii!; to tlif JJiirh Creek fuid Fortyinile foniiiitions. 'I'licre is f'o miK'li intrusive ;:raiiite, but this is solid and coniimiiitively ffesii, wiiile tlie l)asal ^M'anite is altered and schis- tose. A speeinieu of tiiis seliistose granite collected by ;>[r. Ogilvie on the Yukon near the mouth of the Stewart Hiver is described by .Mr. F. 1). Adam.s.' under the head of "Qiiartzoso biotite-jfueiss." This jiianilc l)ecouies more aliiindant to the soulli, so tliat, Fortymile (reek seems to he on tlie northeri. l)oi'der of tlie area in whicli it a|i|i«-ars. Dr. ('. W. Mayes- notes that tiie iirevailinj; rock of the greater i)art of tlie re;;ion lietweeu the Yukon and the St. Klias Moun- tains, aloiii: the Wliiti' Uiver, is a reddi.sh >,n-aiiite, ([uito free from hornhlende. and fre(|uenlly containin.g lar^'e porpliyritic crystals of feldspar. This red j,'raiiite hejiidfris to he Arcliean, and let be tlio Moor on w liicii 'aU'r .sedimentary rocks have ])een deposited. Granite also apjiears to co\e|-a very lary:e area alonjr tiie Tanana I{iver. .Vccordiiig to Lieu'. II. D.Allen,' " the hanks of the I 'pper Tanana, wiiere there is rock, arc f;<'nerally eompo.sed of a yellowisii j;ranite, fast underj^oiiig disintegration, as evidenced by tiie inuumerai>lc par- ticles of mica sus|)ended in the river and the ever shifting cjuick- sands." l'ros|)ector's who have ci-ossed fi'om the Hirch Creek d'stri'.t over In the 'I'anana also report, that the rock along a considerable part of itr- ii'ule is granite, although it may he renuirkcd that their sepa- ratioi. of graidte from other rocks is by no means accurate; and fraso ]{iver, a short distance below Dea.se l,ak(>. The total lengthof this northwest-soiitheasl granitic belt from Dease Hiver to the locali- ties where it has been ri ported on the 'I'anana is not far from 8(M) miles in a straight line, 'i'lie observations made during tlio last sea- son, however, sho\\ that this belt probably does not .-ross the Yukon below its great bend at the Lower Uamiiarls, for although granites are foiiml at this )ioint they appear to be intrusive and younger. The schists which ovei'lie the basal gi'aiiite are found continuously ahmg the northeast side of l he granite belt in the Yukon di.strict of Alaska, being exjiosed notably in the Fortymile and Hireh Creek mining districts. On the iionheast this licit of schists passes under successively younger rocks, so tliat in a short distance there 's a con- tinuous licit of Tertiary strata running parallel with the schists. In ' Am,. Ri'pt. (Iciil. Niit. Hist. Survi-y riimi' new kitIcs, Vi>1. Ill, Pnrt I. p. ';.I1IB. 'Kxii.Mlitii.il tliiouuli till. Vnlf.iii itistri.'t: Nit. ()i'..i,' Mau., V.il. IV, ji. l;i!i. "xpi'ilitii.ii t.. tlio CiipinT. Tiiimim. ami K..yiikuk rivfrs: Si'iiHti' Due.. 'V^"ll^.llin^ttllIl. 1H87, p. 1.111. 'Ann lii'pl. Oiul. Xat. Hist. Survey (ana. la. l.s-T K.'-, new seriw. Vol. Ill, Part 1, p. MB. srnm.] THE BASAL GRANITE. 139 British territory Dr. Dawson' lias not oil tlie o'oso as-sooiation of tho jrranilc Ix'lt with jrncissic rooks and hornblondo- ;inil luioa-sohisls, wliioli, from his ilos riptions, are probably idi'ntioal with tho .-i.-liistoso rooks already mentioned. On the sonth side of tho u:ranito bolt, alon;,' the AVhite Kiver, Dr. llayes^ found marbios and .s(cal cause, but must have originated ill the main crust of the earth; it may be called, therefore, the Yukon goaiiticline. Following the general trend of this geanticiinal ridge, as shown by observations on the Felly, Yukon, and Tanaiia, it will be seen to cut the Yukon at tho Lower Haiuparts. At tiiis jioiiit, how- ever, as already noted, the basal granite does not appear, although the sedimentary schists which overlie it are prosoiit The width of tlu schists is niuoh lessened in comparison with thai at otlior jioints farther southeast along the bolt, and this narrowing, witli tin- absence of granite, indicates that the fold has chised consideralily. If the geanticline persists beyond this point in a northwo.st direction, the basal granite and associated schi.sts should cross the Koyukuk. Concerning this river very little is known. Lieutenant Allen,' how- ever, reports that the country draino, I.V.. lip. fit. p. i:tn * "Op. eit., p. ii")B. ^♦^ 140 GKOl.OGV or THE YUKON GOLD DISTRICT, ALASKA. groat -Ago of tlio granites of tliis bolt as ooniparod with tlio intnisivo graiiitos of tlio Coast IJaiigos, and roniarks the roseniblanco to tlio pi'olmlilo Archoan gi-anites in the tJold Uangcs in southern British Columbia. THE BIRCH CREEK SERIES. Lying on both sides of the bolt of sheared granite which oeeuiiios a posit ion between Fortyiiiilo and Sixlyniile eroeks is a series of schists of nearly unifcn'ui ai)i)earan<'o. This granite has been do.scribod as being probably the fiindaiiiontal rock in the region, and as forming in the Fortyniilo district the axis of an anticlinal ridge. The schists which lie on Ixtth sides are therefore younger than the granite ami older than the other roek formations, which will bo described later. GENERAL CHARACTERISTICS. Conqmsilinn of /'of/r.s.— Those schists are of a general light-gray color and are chiefly made up of quartz, though hieally they pass into darker and even graphitic varieties. The typical rock is a (piartzite, of which the grain is often coarse enough to bo distinguished in the hand speeinien, and of whose dctrital origin the inicro.scoi)o leaves no doubt. In the less-sheared portions the quartzite is hard and white, and shows very little the eflfeots of pressure; usually, however, a decided scliistosity has been produced, evidenced ))y parallel cracks and shear-planes, along which nietaniorphic minerals have been developed. In the move intensely sheared portions tlie planes of scliistosity are sot closely together, and the rock appears to bi; niailo up largely of mica; buti even in such rocks the microscope ordinarily shows that the ("hiof constituent is (luartz. From these typ(»s, which are derived from the alteration of quartzite, there are local gradations into schists, which are plainly derived from finer .siliceous and car- bonaceous .sediments. These schists are met with in small amounts at various points in the series, but especially in its lower portions. There are also found, although rather sparingly, schists of igneous origin, being dikes which have intru<'ie(l into the sedinientai'y .series previous to the shearing. In some i)lacos the contact between this igneous schist and the sedimentary (luarlzite-schist was seen, jiroving its dike-like nature. So far as noted, these intrusions were of granite in its various phases, although the original structure of the rock has often lieen obscured by the subso(|Uont motamorphism. Dikes of various kinds, later than the development of schistositj', are also fre([uent. CorrisponiJrnrr of Hchistnsi/i/ anil strafificntioii. — The planes of sehistosily have boon descril)o original bedding planes, so that liie planes of schistosily maybe takcu guardedly as indicating the true attitude of the beds. DISTRIBUTIDX OF BIRCH t'REEK SCHIST. The liirch Creek series, as already delined. is apparently shown in its entire thickness in the Fortymile district. Above Fortyniilc Creek, on the Vukon, this same series outcrops for a large part of the distance nearly to the junction of the Lewes and the Pelly. Along this line the sheared quartzites contain belts of granite, .some of which is schistose and very likely belongs to the fundamental granite, while in other places it is fresh and massive and .shows plainly an intrusive character. There are also occasional belts of marble belonging to the Fortymile series. Tlie schistosity in all these rocks has a general east-we.st trend or strike, and the alternating bands of diflerent rocks appeal' to follow this same trend. Judging from the attitude of tlioir schistosity, these rocks are con.siderably but not intensely folded, and their thickness must be very great, since a uniform strike and dip are maintained for long distances without any great change in the nature (if the rock. Specimens of schists collected about 10 miles above the mouth of the AVhite Kiver, on the Yukon, and about 25 miles below Sixtymile Creek, on the same river, Avliicli liave been examined microscopically, are essentially schistose (piartzites, containing grains of zircon and a variable amount of muscovite and biotite, formed in consequence of shearing. Below Fortynule Creek the Birch Creek formation was not encoun- tered until the u])peri)art of Birch Creek was reached, where theseries is found to the exclusion of other rocks. The strike and dip of this series in the Bircli Creek district are consistent at different points. Tlio general strike is nearly east and west, changing in the western Iiart of the area, in which active mining is carried on, to northwest, and in the eastern part to northeast. The dip is almost invariably to the .south at a comparatively gentle angle, ranging between 5° and ;50°, and perhaps hardly averaging more tlian 10°. The nearly senucireular course of the strike shows a broad, gentle fold, and since the dip is uniforndy to the south, it is natural to suppo.se that in this direction the Bircli Creek series passes under the Forty- mile series. In fact, the existence of much marble has been reported by a i)rospector at some distance farther south, on the southern side of the divide l)etween the Birch Creek waters and those of a tributary of the Tanana. This information, however, is not necessarily accu- rate. Clilfs of white rock, apparently dipping northward, were also s SPfllR.] THE BIKCH CRKKK SEUIES. 143 ■J 1 scon "11 till' south side of llio Crazy .Moiiiilaiiis, hftwccii Circlf City and the Uirch Creek f,'ul('li('(s. Awonlin^' to a pn.sii.'cloi-. IIk'sc clilTs aroot' iiiarhlf. Owinjj; to tlic very jrentle (li|)of the sfiics in the llireli Creek district, it liore occupies a broaih-r belt tiian at any otlier point examined. ISeiow Cirek' City tlic Uirdi Creek series was not cMeoiiiitereil on tlie Yukon until a point was reached just above llie nioutliof the Tanana, where a scliistose, cah-arcous (luartzite, earryinu(iuartz veins, was found outcro|)pin^'. Froiu tliis point it outcrops freciuently aloiijr the river nearly to tiie nioutii of the Nowikakat, allliouixh it is fre- quently concealed by the overlyinfi con^donierates and sandstones of the Tertiary, and by the sills and ehiys of the Pleistocene. Alon^' the rijrht '.tank of the Yukon, between the inoutli of the Tanana and that of the Xowikakat, is a ranye of low mountains run- ning,' parallel with tlie river. On these mountains the bare rock seems to be lijjht blni.sh-!j;ray in color, and although the structure of the mountains is nuissive, structural planes seem to be visible. The fact that the outcrops along the river at the base of tlies<' mountains arc for a long distance of mieac^'ous and garnetiferous (luartzitc- schists, h'nds probability to the belief that the mountains themselves are composed of schists belonging to the IJirch Creek formation, or to the Fortymile fornuition, which is also cut by the Yuk<»n above the Tanana. This lower belt of Hireli Creek rocks, running parallel with the Yukon below the Tanana, has exactly the .same characteristics as tlie rocks in the Fortymile and Birch Creek districts. It has the same rock types, the same schistose structure, and the same ([uartz veins which have ordinarily been sheared with the inclosing rock. The series here also contains gold, and abotiti the mouth of the 'I'ozi- kakat a large sheared vein of quartz, carrying gold, has been worked a little l)y Mr. G. C. Bettles, the trader in charge of the post at Tanana. THICKNESS OK THE HIKCH C'KEEK SERIES. From the area which the Birch Creek rocks occupy between the Pelly Hiver and Fortymile Creek it is clear that their thickness must be very great, even if much folding is assumed. In the Fortymile district a cross-section was obtained alon;, the Miller Creek trail, where the .series forms a belt about .S miles in width. Along this ))elt the dip of the schistosity was observed at numei'oiis points, being on an average about 4U^, which was also the dip of the intercalated marbles and quartzite-schists of the overlying Fortymile series on Fortymile Creek. Inasmuch as the dip is nniformly to the north, there seems to have been no great amount of minor folding, and the .S miles of oiitcroj) witli an average dip of 40^ gives a total thickness of about i5,()U() feet. In the Birch Creek district, as already stated, the dip is much IM (il.OI.OUV OF TIIK YIKON G01,U l)If*TKICT, AI.ASKA. slij;lili'i, iivcrjij;iiitr ixTliaps in tliu iiciirlilinrlidod of lii . 'I'lic widtli of llii' Im'Ii ill which Ihi- scries outcrops, however, is iii.iieli greater iis niciisiired from tlie iiioiiiitaiiis Just north of tlie IJireli Creek fruiches ill a southerly direct ion to llic h)cali1y where iiiarbk" lias Im'cii reported by |)rospeetors. This is iirohalily Uw. total width over which the series crops with a iiiiiforiii tlip; for iiortli of tlio I'.ireli Creek fiiilches, on tlietrail to Circle City, schists similar tollioseili the Forlymile formation arc found cropping, and fra^'nlellts of mar- Ide ill the coarse snivels; and marbh' is said to outcrop on the north- ern eiiil of the rid^'e of mountains lyiiii,' Just west of IJirch Creek. 'I'lic semicin'iiiar curve in tlie strike of the Jlircli Creek (iiiartzites, as delected in the miniiij; district, Joined with this evidence of the erop- jiiiii; of the Fortymile series farther north, goes to show that the folil is in the nature of a comparatively >,'entle dome from wliieh the strata dip away on three sides at least — to the north, south, and east. It is at the jirolialde siiiiiniit of this dome that one end of the line ineasur- iiij: the width of the Ixdt occupied by the I'dreli Creek series is taken. At the olheror southern end the marbles reported apparently iiidieato the existence of the Forlymile formation, iiiuler whieli the IJirch Creek formation passes. The total lenjrth of this line as thus meas- ured is about :.'.■) miles, and thi.s width, with an average dip of lo", gives a total thiekness to the roeks of the ISireli Creek .series of not far from J."),im«i feet, which is the same result as that reached iude- peiideiitly, with ((iiite dilTereut data, in the Fortymilo district. .MICHOSCOl'IC STrilV OF HIKC'II CKEEK ROCKS. The igneous rocks which arc intrusive into the altered sedimcn- taries of the Birch Creek scries will be described later, and for the present only the nature of the original sediments and the derived schists will be considered. As already slated, the nature of the rocks in the Uirch C'reek series is oomparat i vely uniform throughout its whole thickness, and the rocks are also identical in aiipearance at the dilTerent localities mentioned above, which are hunilreds of miles apai't. Nearly all specimens appear in thin section as slightly altered quartzites, composed of inter- locking grains of (juartz of nearly uniform size. In many eases the outlines of original detrital grains are plainly visible, being shown by a faint ring of indeterminable dirty material, which must have coated the surface of the original grains. In other cases the outlines of the original grains are very faint and often can not be discerned. This is probably due to the circumstance that the surface of the grains was entirely clean before the additi(Ui of the second quartz. In all ea.sestlu,' interstices between these original grains have been tilled by crystalline quartz, which has grown onto the grains in crystallo- graidiic continuity, as is usually the ease in ((uartzites; so that the rock is now composed essentially of irregular interlocking grains. KA. Kri'iiii I 'I'llK KOUTVMILI-: HF.KIKS. 14.-) Thf widtli icli j;''"'!it''i" ii'di Ci'ct'k iiiai'lili' lias width over llio lUi'ch to tlioso ill its of iiiiir- tlic iiortli- ircli C'rt'ck. lartzitcs, as if tlu! crop- lat tiie fold 1 tlio strata (•ast. It is III' iiioasiii-- .'s is taken. Ily indicate the llireh thus iiieas- dij) of W, M'ies of not u'lied iude- [■ic't. 1 sodiinen- iiid for the lie derived 'reek series 1(1 the rocks mentioned siieciinens led of liiter- ly cases the fj shown by lave coated lines of the lied. This the y:raiiis rtz. In all en filled by I crystallo- so that the iiiff yraius. lifsidi's t\\\nr\/. tiii'ic iiic rarer iiiinerals, wliiiii iir in rouiMlcd firaiiis aii>l'l>"'i' l'"i'' "'' l'"' ^''lic- inlo the iiiarlili's of the Koilyiiiile formation. In some <>( ili.- liiivli ( ici'k scliists there is a larire amouni of carliomu'i'oiis luaiier, sonifi imcs eoini)lelcly alteri'd into graphite, which is also cvidi'iiliy an orl;:iii.il constituent. Mctamorplii'c minerals arc usually nincli less in amount llian ilie ori-inal deliital matciial. hut are present in nearly every si-clion. The mosi iiinoii nictamorphic mineral is mnscovite, wliicli i urs esiiccially on the slippin;; surfaces, or planesof >chislosity. I'.iol ilc is often found, sometimes inclosing /ircon or sai;cnitc wclis; idiinnaliiie is very common, and tcarncl is conspicuous in some of llic rocks; irrecn liomhlcndc and a<'l iiiolilc arc occasionally met wilii. .\m>ilicr class of secondary minerals which |)rohal)ly li;i\c a ^iiudill.v dilVcicnl oriiiin, Iteiiiif due to aqueous rather than to dynamic action, ccuisists of 1 asioual, sometimes aliumiant, crystals and ^n'aiiis i>( pyrilc, and iron in other forms, such as specular iron, limoiiilc, and sideiile. Marcasite is frc(|uciil in perfect crystals, and f'opper pyrilc, ofieii yieldiiiii' a niccii slain Ironi dccomposil ion, is mil unusu;il: naleiia is sometimes found in i;i-aiiis in the schist as well as in i|Uarl/, \ ciiis which the schist incloses. All these secondary minerals, whetlier the result of shearin;; or deiicndi-nt upon ai|iieous causes, nceiir in evident relation to the slippinj,' planes in the i k, as can lie seen in thin section, and .ill often form perfect crysijils or iriei:ulai' plates which liave,u;rowii around and inclosed tlic oriLrinal delrilal grains. THE KORTYMILE SERIES. (iKNKK.M, IIKSCIMI'IIDN. ( )verlyiiii; the schistose ([liartzites of tlie IJircli (reek scries is ,i con- siderable tliicknessof inler<-alalc(l nnirliles and (inarl/.iles, with hofii- hlendic, micaceous, ^i'ainet iferous, and sometimes ni'jiphilie schists. The marl lie lieds, however, arc f lund in all jiarts of the format ion and form its chief (list inctixc I'c.itiire. To these rocks arc i;i\cn the name " l''ortyniile series," since i iiey are exposed in ;rreal detail aloiiir l''orty- niile Creek, and there alTord lieiter oppoi'i unit ies f in the field. This is well shown at the junction of .Moose 18 GEOL, PT '■'> 10 '^■™5H lu; (ii'.oi.ixiv or Till-: vikdn (iui.u idsTiucr, ai.aska. ( rcik uilli I'lPilyiiiilc (reck, where there oeeiir iiiterlH'ilded tniu'liles aixl <|iiiirl/ites which ;ire in tlie lower pari, w Idle the hulk id' the rocks <'onsisls of hornhU'iKle-, nnca-. and uarni'l -schists. The m.irhle is everywhere preseid, often in thin layeis, hid increasing; in some beds to a thickness of several liundred feet . T)IKKS. Iidrnsive ij^neous ro(dvs .are alnindant in the l'"oriymile series, and are of dilfereiit a^'es. Some h;ne boon so altered by the .same jiroc- esses which ha\e produced crystallization in tlic sedimeidary series that their iuneous nat ure would often liarilly be recoH;ni/.ed without tlie aid of the niicroscopi'. 'I'hese rocks appear to bclonfX mainly to the irranitii- ;ind dioritic families. ( )thor dikes which have been only sliiihlly sheared show much less nietamorphism than the inidosin;; rocks, and leave no doubt as to their iifiieoiis and intriisi\e nature. l'"inally. there are dikes which show no nietamorphism whatever, and which must have entered t]i(> rocks subse(|uent; loall important.inovo- nicnts anil st rains. On l''ortyiiiile Creek these dikes are everywhere abundant in the bamli'd marbles, (piartzites, and .schists, especially on the South Fork of l-'ortymile Creek, between th(> junction with the North Fork and with I'ranklin (iulch. Here thi'V often form immense masses, the different varieties cut I iiiLr across one aiiotlier in a confii.sed manner; and tlie sedimentary rocks are disturbed and metamor[)hosed so that tlie general structure was not surely niaih.' out. In comiiosition t hese dikes show a ^'reat variety, but they do not admit of any strict classilicat ion, since they jjfrade into one another, and the rock of any one dike is i-andy exactly like that of any other. 'J'here are vjiriations from the most basic to the most acid, and the I KA. ('(1 niiu'l)l('s I'lll extent, or r>{) IVot les. Fl'dill I'deks, such lese scllislH lit tlie iniii-- uliists ill .1 t would be zile-scliistH t the l.itler al tliMii tho ety 1)1" new ileiide- and lists, otteii ich are still ocelli' most lart/.ilC' •'" lU'iihleiidc-, ■sent, often of sevei'al series, and same ]>roe- iitary series '.ed without i mainly to e lieell only le inclosiii}.; iive nature, atever, and rtanl.move- laiit in the South Fork 1 Fork and masses, the ed inaiiinM'; Dsed so that they do not me another, f any other, •ill, and the SI'l'tlK.) TIIK I'OKTVMll.K SKKIKS. 147 chief forms may lie enumeial<'d. conmieiicinu with the st liasii', as liyroxenite, lioi'iililendite, diorite, diorite-porphyi \ , «iuail/.-iliorile. syeidle, liornblende-frranite. iiorphyry, and aplite. The most liasic varieties, pyroxenile and horiil)lendlte, contain considerahle ipianii- tiesof pyrrholile and other nn-tallii' minerals, while the extremely acid aplites ehaiif,"' j,'radnally into i)iire ipiart/ vidns. jiotli ac'id and basic rocks often iir in j^reat masses, on the holders of which are aliundaiit line strin^'ers into the sedinieiitary schist, showin;; I heir intrusive nature. The dilfereiit dikes often cut one another, and it is usually the case that when two dikes of ditlVreiit varieties inter- sect, the phelioiiiena show the nioie acid dike to lie the younger. The nioi-e basic varieties of the dike rocks are in some jilaccs schistose and ill other |ilaccs massi\c, while the extremely aciil rock, such as I lie aplite, shows no schistosily or other deformation. Some of the hijrhly iiietaiiiorphosed ijjneous rocks, wliicli are evidently the oldest, con- tain f these two the less abundant has an intimate con- nection with the aplite (like, for it ^railcs into these rocks in struc- ture and coiniMisition. and cjin often be traced into it in a siiifile (Miti'rop, the aplite cljani;iiiif to a vein com|iosed of quart/, and fcld- s]iar, and this, by disappearance of the feldspar, into one of quartz alone. These veins cut across the schistosity in the fashion of dikes, and have not been di.stnrbed by any movement in the rocks. Veins of the other .set are very abundant, both in the Fortymile seriesand in the iinderlyinij; I li rch Ci'cek series. 'I'hey o<'cur spariii,i,dy intl Idest and most schistose dike rocks, and not at all in theyoun^'cr rocks, such as aplite. .Moreover, they afford abundant evidence of havin;; been subjected to j^reat crushint; and deformation to;;ether with the inclosinii rock, and it has already been mentioned that these disturbai s have not a<'te(l at all u|)on the yotin^'er dike i ks. This set of abundant (iiiartz veins, therefore, is (piite distinct from that which is connected with the dikes and has a considerably j^realer ag(>. These xcins are usuallv iionpersisleni, so that both ends of a j^iveii vein can usually be found in a lar^ic outcroii. This iioiipersistence is probably partly ori;j;inal and partly due to faultiiifj; siiV)se(iiieiit to dejMisition. In jjfeneral the veins are parallel with the schistosity. althou^di sometimes they cut across it at varying anirles. \Vhciic\cr the inclosinu; rock has been niiich distnrlicd and rendered markedly schisto.se the elVecIs of the movement are shown in the veins also by a stiH-tchiiiir of those which are parallel to the -.chis- fosity, and in exireino cases by a veritable shretldin^f; while those veins which cut across the schistosity are faulted anil draiigcd along I MS Gl-.Ml.OCiY Ol- Tin: YI'KDN' 'ii'I.D KI'^IKU'T, ALASKA. I|„. plMiirs ..I' IM..VCMIC1I1. Tin i'lV<'<-l of this slii'iiriiiir is sen in all inirrosrupi.' s.M-licms c.f the viMii-, h.Miiii- iiiitiiitVst.'d \>y mm. Tons inl.Ts.-.-liii'r sflsof paralii'! Irad iir.'s, aii.l in ili" wavy cMinclinn of the .iii^r (;iiarl/ veins arc ol'lcn violcnily conlortcil. 'I'licsc veins, wliellicr .eeiirrinii' in tiie I'orlyniiie .scries or llie liireli (reek se-ies. oflen eonlain pyrite. sonieliiues i;alena, ami occasionally free irold. 'I'licy arc prohaliiy anioim- tlii' I'liid' sources ol' llic s:ol>i in liie ^■||l , so thai in tin r present eondilioii ihey are lirokcii and elonuiileil. It therefore a| pears thai snii.seipieiil to the initial sh, irinn which produce I ilie niciamorphic niincr;:ls and ^axe rise III ihe i(na.t/, veins ihe mo\cmeiiis in the rocks continued idoii;^- the si.me |ilanes, prodiicini; ^kiealcr inelaiiiorpliisin and defac- ing;, in part, the results of tin' earlier movenient. It has al ready lieeii staied ih.ll some of the dike reeks arc prol'oiindly sheared and others only sliuhtly, whil-' those which ,,re e\ idently \onii;a:esl lia\e I'-njer- ^■one no deformal ; whaie\er. ll is prolialile, llieii, (hat llienio\e- mcnl which prodllci'd the present >elii'>losc slillelnie colitiniled in operation a .eiy Iniii;- period of time, during wliiidi [leiiod maiiyollu-r chan;j;es occurred in the rocks. c,i|,|i|Mi AND lAIl.TINti, As a rule the rocks of the loriymile scries arc not jrt'fnlly faulted. l''riiin a jioiiit on l'ort\niilc Creekalioul k' or l.'i miles alio ve I'orly- mile I'osi. as far as (»"|iiien ( I'ctdx a distance in a slrai;i;lit liiic, 3i MCA. Ht'cii in all • IMIII. 'foils ailK'lloll (if )11. WIllT.' ic iiH-l(isiii|; IS, wild licr ("■icS, ufll'll ;(.l.l. 'Ilirv ilic Niikoii iiilt'i'lii'dilcil til III' MlPMSC iiisitidiis ii|i It;- Ilic I'.ircli ,' scliistiisity !• the ililcl- ii,'irlili-s anil il lujc' lit' till' I'liipiiifiit lit' K-ll as llcH'll- niii'il rliit'lly a ii'siili (if iiltly I'ciiiiicil laiiinls ciiii- lllil\ Cllll'lll , I, ami cM'ii ly iiiiiloiilil- lll'tl-ll lllM'll nliliiiii t lii'y I)>C(|I|C||I III iini'i::ls ami ccilll illllc'il mil ili'tar- Insuiy Itccii I ami Ml lii'i's ia\i' i"ii|i-i- l( lll(> IIHIM'- >M< iiiiii'il in many iillu'i- lily I'aiiltfil. liDVt' l-'iirly- rai;;iit lint*, THE koiiivmim; skhies. 149 ilisi'i'trarilinir tin- siniinsit ics nl' the ii\ it. nf J'l or :>o inllfs — tlicri' is a iii-aiiy iiiiil'iinii strike ami ilip: this strike is imrt lieast, nearly par- aili I with llie i^eiieial i-iiiirse iif llie ri\ei', while the ilip is iiiirthwesi at an a\ eia^'e aiiirle " . Aliin;,' this part iit' the river, therel'Dii the l'"iiilyiiiile serie^ lias a ir»'neial ilip aw.i\ t'rniii the axis ol' the Kuriymile ant ieliiie, .Miove o'ltrien (reek, es| iallyniilhe Sinitli Kiirk. the rocks have lii-eii j^reatly ilisi nrlieil liy ilikes of iniiiien.>., si/.e, so that there is no iiiiit'oriiiily, ami the ;;eiieral striietiire ean not 1m> elearly iiiaile out. 'The aeeonipaiiyin^ (itrnie (li;;-. 7) shows an oiit- erop of inarhle with some intersi ralilieil sehisison I'lirtyiiiile (reek lielow ( »'lirieii t'reek, the rocks as exposeil ha\inira iiiiironii ilip. Minor I'oldiiifr. even criinipliiifi, is locally fomiil, especially in that pari of the series which is most traverseil Uyilikcs. This minor folij. * in;; has iil'teii come alioiit inter than tli<> nioveiiieni proilncin^r the planes of sehistosity, I'ol' these schistose planes lollow all llieciir\es ill the I'olils. .\ specjnieli of colitorteil ipiart/.ile-liiol ile-;.'ai|lel-sehist, eviiil'its some liamis essentially of jnire (|iiai'i/.i1e. while i.arkcr ones « oniaiii also iiiiieli liiiitile ami ^rarnci w ith iimseov iie. Tue schist o^lty appears to follow all the curves of the I'olils. ,'iml micro>copic si inly shows that liioiite ami ;;ariiel, both iiieiamorphie iiiincrals, have Itceii broken ami stretcheil by sheai'inu pre\ ions to I he folding;. .\l various pointson l'"orlyiiiil(> (reck faults are often shown dia- i^raiiimatically ill Ihcclitrs.bi' the aiiioiinl of imiN'eineiit coiilil not In; I I l.OO (iKol.iiCY or Till'. VI-KON (iOI.O DISTUK'T, ALASKA. iiscoi'laiticil l)y surli ciirsorv uliscival iuii iis Ihc liiiiilccl time lioriiiittcd. F'n:. s is fntin ski'tfln's dI' sm-li ImiiUs. .mix IS. 'riicii' is no mii\i'i's,il jdiiiliiii; in lln' i Us oi' tlic r'niiyiiiilc sci'ics, ])iil ill ilic iiiosi iiiltTiMi |Miiiiiiiis tlicif is dIIcii I'oiiikI a very pruiiii iii'iii sri of Ji till I plain's. «liii'li (Mils till' sell islosily and I III' loldinj,' ami is pniliahly dill' In Im-al raiiscs. Al twn pniiits dii {•"iirlyiiiiii' (reck when' llic'sc jniiits were cspci-ially well di'\ eloped their at lil llde was talNi'ii. and was fnniid ici he in iiiie ease, strike N. !S."i^ NV., dip :in ' N., ami ill another strike. N. 7-"i K., 'lip 7'> S\V. (■(iMIi PSilli IN of polilYMII.K Ii'OCKS. .\s alieaily staled, the l''cirtyiiiile rucks eiiiisisl essoiltially n( iiiarliles and i|iiarl/.iles, wliieli jiass into linriilileiide-. iiilea-, frariiel-, and ^'lapliile-seliists. Ily the aid of tlie iiiii-roseope tlie o.xaet striiet- -^MGiul-iTC SCmiST GARBLE MARBLC AND INTCRBCODtO SCHIST Kid. "^ I'auit-' in I'.r-tx mil'* s.-rit's. lire (it' these ditTereiit \ arieties and tile line uradat inns into one anothi-r which they exhiliil may l>e acciiralel.x' studied. M'lil'li. The marhles are (il'ten (|iiile pure, heiliir ;iia(le up en' irely of coarse, interlockiiiir plates ol' crystalline cah ile. These plates often show liciidinu: and sometimes enishiny as the result of shearin;:, lint scarcely aii> development of new iiietainorphic minerals. Tlie tils' staL'e in the Iransilion ol' icaililes to (|iiait/iles is shown hy the pr'scnec of more or less niiineroiis del rilal Lri'ains of iniart/. « hich are inclosed intlieealcite plates; Ver_\ often Lriai IIS are ('III i I'ely inclos('(| ill a siniile ealcite crystal, showiii;; that theealcite is re;;eiieraled or reerysialli/ed from its (niirinal form. In oilier pails t he (piarl/. grains increase in iiiiiiilier iiiit il the rock is cs.sent ially a ealcare'ois (piart/ite, liein;.'' madi> up clii -Ily of (|iiart/. u:i'iiins cemeiiled liy ealcite; and in .some sections there are alternaliiiy: /ones, some of which arc tine (liiarl/it<'. heiiiL' coinposed of del rilal (piart/, .'grains, cemented liy see- oinhiry (|iiarl/. while others coiiiaiii less nnmcrons oiiart/, irrains iiiclos( d in caicile. thus ^howiiiLT a perfect I raiisil ion het ween the 1 wd rocks. (^iiiiii:il< . — The pure (piartzites show their Iriie nature (|iiite well in the liidd, and under the micidscopc exldhii comparatixcly lili le 1 liiM'iiiitlcd. iiilc scries, CIV lifiillli ililiii^ mill iiili' Ci'ci'k I ii imIc w.'is ip :io N., cntially of . ^ai'iii'i-, ^fict SlI'llCl- hlMiai-] THK FOKTVMILE SEUIl'.S. l.)! one aiiDilicr lip ciiUrcly licsc plali's il' slicai'iii;;, crals. Tlic lowii liy llii' /,. wliicli ail' cly iiicliiscd ;cii('rali'il ur uarl/. t;raiiis IS i|iiarl/ilc, 'III': ami in I'll arc tnif [iloil \>y sci'- lai'tz LTraliis ecu t lie I wo I' i|iiilt' wi'II itivciv lililc 4 iiii'laiiKii'pliisiii. N'cry nflcii tin- i'i>iiiii1(mI fnriiis ul' ihc i>riv:inal ilclillal gi'aiiis nt" quart/ may Ix' (lisi'ciiicil liy Ilic faint Mm- nt" (lii't> kaoliiiic material which IiiiiiikIs tliciii. licsiilcs Ihc ((iiarlz strains there are also oc<'asinnally othiM" detrital rra^riiicnts, anions which feldspar, /.ir- coli, and apatite may he noted. Asa rule the i|iiait/ites arc t rav- ersed liy many parallel microscopic cracks, which are plainly the result of shearing, and in evident conned ion with ihesc shear /.ones are inciaiiiorphic minerals in Naryiiiii amount, such as miiscuvitc, toiirmaliiic, and garnet. Pyrilc is also frciincnt. (,>iiiiH:j-iiiirii-Nfliisl. — These schistose ipiarl/ites chanirc very i,'iadil- all\' into more iiietamoriihic i-ocks liy an increase in the amount of ]iii'*aiii<>rpliic miiKM'als. Amonj; these an important class is distiii- jriiislied liy the jrrcal dcvclniimeiit of mica, which is chiellx liintite, altlioiii,di somctiiiics inuscDvite prcihiminatcs. In thi'sc nicks sunu* zones ordinarily retain the striictiirc of the piirei- i|iiartzite-scliist, while in ollii'i's Mie si'coiiiiui'iiin-n|-a s.Mli iitaiy i.M-k. Iirinjr posf'l mainly ol'.l.'tri- tal .|uart/ ;:raiiis, uitli o.-casimial fcl.lspar, /iivoii. aiialilf, and oilier iiiilirrais. <;nn„lifir. ale Ncliisl> which .lie d i>l i iil;ii islieil by the pri'Sence of ainindant carlioiiai'coiis and liiapliilic iiialerial. This ;ji\cs I he rock in the hand specimen a Inst ions, dark-u'iay color, and under I he micro- scope >liillin^' part iides of yraphile are e\ ery w heri- seen. liesides I he Lniiphite. whiidi is ^nlioidinate in amoiiiii to the oilier iiiini'ials. tin' rock consists iiKoily nf (|iiait/. hiolile. ami mnscoxili". >o that it is realU an impure caildiinn'coiis form of the c|ii.irt/.-iiiica-si|iis| . ( 'iliiiiil' -sriilsl. ,\ \ ;iricly of I he uraphii i<- schists found in the llircli (rei'k district, a Ion;;- I he Irail leadiiiir from Circle ( it y to I he i;iilclies, is iiiarked liy alnindaiit cyaiiiti. in shori. .-imii pri>nis. In other respects the rock is essentially a iri'aphitic il:s. — There are sometimes oliseiwed dike rocks w liieh have lieeii so iiietaniorpliosed Ity shearing; that t heir t riie nature can often not he eerlaiiil> told in I hi' liehl, although i;enerall> deier- iiiinahle under the microseope. In these rocks the original minerals are proci'Ncd. allhoiiLih a marked and in places a profound cala<'his- tic st met lire ilefaces I heir arraiiyemeiil . .Viiioiil; these dikes varieties of the granite, diorile. and syenite families are most ahiiiidant. n|{|(;l.\Al, NAiriiK (ij- I'dlirV.Mll.i; ItlMKS. Tho.se portions of llw I'orlyiiiile series which are least metainor- phosed all' plainly sedimentary rocks, heinir iiiterhedded marhlesaml piMim] TlIK I'OHTV.MIl.i: SKIUKS. 153 (liiiirl/iti'S. In till' iiiiii'c altcr'cd rocks, \vlii<'li licccnii.' sclii>lo-M'. tlii' inarlili's slill alliTiiiilc will) Hif sdiislos.' liamls. sli.iwin.ir thai rvcii tliiM'ari' ol' scilimciitary orifriri. .MmfovtT. tin- inii'nixMi],.' >1mi\\s a ■Ziailiial tiaiisilioii I'l-oin tin- nearly pni-c iinarl/itcs Id ili>- IiIl'Ii <-rvNial- linc M'hisls in wliicli the jrnnlnal clianiri- liy tin- ilrvflitpnu'nt of ni.'ta- niorpliii' ininiTals may Ix' ohscivi'd. In llicsf 1 lansilions ili.- altfiiia- tion of liands of pure (iiiait/.itc-si'liisi willi oIIht liands c.inaininir darker mclanioipliii' niincrals. such as mica and iiornldcndc. suiTLTcsts linil tlicsc daikcr liands nprcscnl impure parts of tin- iniirinal scili- mi-nls wliicli coiiiaitu'il a laij,'c jiropoilion of basic dctiital malcrial. Tl -cmnincc of (iinirt/.. feldspar, zircon, apalitc. pyriic and snnu" liioiilc anion.irtlic jrrains of tlicoi-i,i.'inal sedimentary rider tliat. tlic liands which are now chani;cd into mica- and hornlilendi'-sclii>l contained oii^rinally n hdelriial niateiial deiived from the darker minerals in the uranite, while ilie pure ipiar-t/.-scliisIs were maih- np chielly of ^;ranili<- quarlz. 'riiere is also evidence, in various parts of the scries, of conirhnneratt's which are in general consideralily niela- morpliosed. In the nppei' parts of ihe scric-, the irraphilic schists indicate a si ill iiiorc impure scdimcnl and prolialil> the pieseiice of oruani<' lili'- I'hc scries, ihcn, orii;inall.\- consi-led nl aliei-nalin^ hands of limesloni'. sandstone, conudonierale. and shale. ,i ml il appears ]ii-olialilc that the lower part I'onsisled chietly of pure •..indstoiie while ihc upper pari was more impiii'c and c.irlionaci >. iHsiiiiiirriiiN UK i-iii;rv:Mii.r. skuiks. On l''ortyinile ( ri'ck ilu' rocks of ihc I'oriymilc series ont<'rop conlinnously from a point >'• or 7 miles aliox c the post up to a point lieyond I'ranklin tiiilch, which empties intothe South l"oik. r>clwcen l-'ranklin liiilch and Chicken (reck, and lieiween I'ranklin (iulch and Napoleon ( icek. the I'orlyinile series is overlain liy i;recn slate and impMii' calcareous mils licloiiL;inu- to a younu'ei- formation, which will he dcciilieil as I he Kamparl series; and also liy coiii:lomi'rales, •irils, and saiiilsiones.u ilh slial> and i'oal\ licds. wliicli will lie descri lied as the .Mission (reck series and which appear Ioo\erlie um-onforin- alily liolh the p'orlymile series and the yoimirer .i:recn slati' and irril formation, .\ short distance alio\e the .juiiciion of {■■ortymilc (reek wiih Ihc Yukon the nicks of the j-'orlymilc series arc inerlain liy sainlslones and shales « hiili ar nsidcralil.N' altered in jilaccs hut which are still disi iin'li.\- youniier. and are also rcfi'rrcd to ihe .Mission {'reck scries. On the \ ukon, •"> or H miles ahovo the uionih of Sixtyinile (reek, a series of pure while nuirliles interliaiided with micaceous schists was noted. These undonhtedly lielonu to the same formation as the lieds which have been des rilieil on l''ortymile Ci k. McConnelP also I .\iiii K.'p' '"■"' ^>'" "'■" >>iii'>''y. < ' iii.i'lii. I^Nt^^'J. iii'w .-HTii.-. Viil. IV. 1.. ItiU. l.')4 flKOI.OGY OF TIIK Vl-K(>\ GDI.H DISTRICT, ALASKA. iMiti's llijit sonic mill's iilxivc Fdil Hrliiiiirc ;i Imiid ol' liincstono and (lark aiunllili's. li'aM rsccl Ity luiiiii'roiis (|Uiii-lz \cins and associated Willi micaceous scliisls. cfitsscs ilic ii\cr. Tlicsc arc |iriiltaltl>- also lo be assi;riicil III llic Korlyiiiilc scries. In lilt" liircii (reck ilislrici no opiioilnnily was liaii lo sliidyllio FiMlyinilc scries III any cMcnI. On llicirail liclwecn Circle Cily and llie irnlches, liowcvcr. niarlilcs and lii;rtil>' mclaniorplioscd niica-sciiisis arc found in llic di'liris, and iliis didn'is is c\ ideiilly derived I'roni Die Idlls ininicdialely adjaceiil. Al one point also a micaceous schist, carryiiiir much cyanilc and li('|i)ii;,'inj: to a frroup which occurs aliiiii- daiilly in Ihc I'orlymilc sci'ics, was found in oulci'op: and alon^' Iho Cra/y Mounlains, which lie lo Ihc west of ihis trail, marlde is rcporled to occur in outcrop. The i|uai'lziles and i|uarlzilc-scliists of the Rirdi Creek for'matioii, which form practically I he iinl.\' i ks outcropping; in tlic ;,'ulchcs, ajipcar hy their strike and dip to form a domediko uplift, from Ihc center of which the sli'.-ila di]( away in nearly all direilions. thus pa.ssin^ under the I'"orlymilc series, as here noted. On the south side of the ;rulches marlile is rc|iorled liy prospectors as occurriii}.' near Ihc divide liclwecn the ^'ukon and the 'I'aiuina waters. In the Lower Kainparts of the \'ukiin, almut l.'i miles ahoNc the moulh of Ihc Tanana, arc onlcrops of calcareous i|Uarl/.ilc-schists. 'I'licsc rocks arc overlapped liy the uiicoiifornialily oxci'lyin;; con- },'lomcralcs and trrils of the Terliary. >>lhal eoniinuoiis oliser\atioM can mil he m.-idc. and ihc a|ipcMralice of Ihc nmuiilains su^rucsts that. there has lieci nsiilcralile faulting' on a lai;e scale, liclow the Tanana. however, the i|uarl/,iles and (|Uarlzile-schists of the IJircli Ci'cck formation outcrop for many miles alonjr the Yukon, except where ii\crlaiii liy Terliary or IMcisiocene iieds; showing' thai tin* outcrops liisl alluded to ai'c p'rolialily lo he assigned to the l'"orty- milc series. .Moiii; the Telly Ki\er, which runs close to the avis of the ;;reat. {Tcani iciinc, I)awson' has noled limestones and micaceous schists, which prolialily tieluii;; to the same series as has here been de.serihed. (»ii the Wliite Uiver, Pr. Hayes- states that on the southwestern side of Ihc fireat hell of granite whi'di covers most of the district through which Ihc lower White Uiver Hows there is. liclwecn the Uonjek and Koidern rivers, an area composed .ilmosi eniirdy of while marblo and talcosc schist. It is probalilc ihat these rocks arc to I irrelaled with the I'lirtymilc scries, and it may lie noted thai they lie on the iippiisiie side of the ^■ukon L,'eantielin(! from the rocks aloii^r P'orly- inile Creek. IIIICKNKSS (II' I'dJiTVMII.I': HdCKS. No satisfactory cross-section of the l-'oriymilc .scries was oliiaiiicd, so Ihc thickness can mil be y:iven: il is probable, however, thai it is somcvvlial less Ih.in thai of the I'drcli Creek scries. 'Ami. U.'iil. 111',.!. Nut, Hist, Siirvry I'liim.lii. I-«7 '•«. new ....i-ii's, V..I III. I'lii't I, )i, .'KH. »Nii( UfiiK, .MiiK . Miiy l.'i. iwr.'. |, ||ii Tin; FORTVMILE SF.RIKS. i:.5 KESIME. I 1 'I'hc Fortyinilo . series cniisislcd ori'jfii'.ally "t" a ••i>nsi"leral>lc iliick- ness i>t" liiiM'stuiics, saiidslont s, shales, ami (•(iiifildiniTalcs in a'.leiiial- ilijr lii'n ami persistent. i''roni this il appears that tliemo\erncnt in the rocks, in'odnein;; various defiu'niations, lasted I'm' a lout: period of tiuH-, and that dnrini; all this period dike i-ocks were int rinlecl into tho sei'ies at intervals. I THK RAIVIPART SERIES. i'i;i:i.i\iJNAi;v st.\ti;mi;.\t. .Vt a hinhcr hori/.on than the rock> of the p'ortymile series, ami probaiily directly ovcrlyin.i; them is a scries of ^rcal ihi<'kness, whose rocks arc characlc'ri/.cd ihroui;liout by nearly constant litho- lo^rical 1 uliarit ics. These peculiarii ies j;ive a certain uuiformil \ of appearance in the Held, and. when carefully studied, point to a simi- larity of (liahasf nccins il proliabiy rcpivsciils for I lie iiinsl part sill lari' Mows, aillmiiu:li it also is I'lmiiil in tlikcs cntl in;: the associatcil 1 ks. With the ilialiasc an- found tnlTat'cous scilinicnts. wliicli an* (Icrivfil fill iicly from the ilialiasc. ami iIh-sc loini a very larp" and inipoitant |)arl of the scries. 'I'licy ;rrail<' into inipuri' linicsloncs, often L'laii itie. and liard irreeii shales. The ,i;eiieral .ureeii color of tlic foiiiiatioii is due partly to the ilc\ elopiiieiil of ulaiii'oniie in the tiitVs and inipiirc s ■diiiieiits. Hiil cliiell,\- to the iireseiicc of .serpentine, chlorite, and oilier i^recii minerals aiisin;;' from the decoiiiposil ion of the i;riieoiis rocks which have coiilrilnitetl towanl the iiphiiildin^' id" the I'litile series. HlsimniTION AND (IKNKHAI. Kl'.SClUr'TIOX. F'irh/iiilli Criik. Sntilli l-'iirk.—iU\ the rid;,'i' dividing: Chicken (reek from the Soiitli l-"ork of l''ortyiiiile Creek, ami in a correspoiid- iiii; position in the lied of the South {''ork itself, the niarliles. Iiorii- lileiide-schists, and i|iiart/ite-scliisis of the j-'ortymilc formation are oxcilaiii liy roeksof decidedly yoiin.irerappearance. 'riiescroies a conipara- ti\cly narrow hand. Ill Inn II luirliiuiih Criik iruil Missiuii Crnk. — .Mon;; the \'iikoii for ahoiit -•"' miles hclow Fortyniile Creek are hiaek whales and tliin- hedded sandslones, which are coiisiderahly faiil1(>(l and folded, and wliieli are locally sliu'litli^ nicliiinorphoscd, hut never so iinndi so as tiio oilier formations wliij-h have heen deseriheil. These hIaek shales and sandstones appear to Ixdoii^' to a yonn;j;er fornialion, and have been eorri'latod with Ihu eoiif^lDiiierates, saiidsloiios, and shales which I J-lTIIUl TIIK KAMl'AKl' 8KWIK8. i:. o\i'i-lic niiciiiil(inii,ilil\ iIk- ;ri'<'fii nicks i>t' llic Uiitnpiirl rmiiijil inn cm Niipdlciiii ( rt'ck !iiiil (liickcii I'fi'cki ami In llic^^i' rocks \tn> liccii jrivcii llic iiiiiiic Missiiiii Cicck scries. Al II piiiiii aliiiiit :.'•") miles IicIdw Koiiyiiiilc C'l k llic shales ami lliiii-hcililccl sandsldiu's arc succeeded by massive dai'k-L'rceii rocks, wliieli clwiii;:e in plai'cs to dark-u'iay or ilaiU-hliic color. Iml still iclain their massi\e si rnetnrc and their peculiar lilliolo;:ical charae- tcis. .\l lirsl these i ks alterualc in broad bamls with the black shales uliii'h have alreaaiiie character but lia\ i' a .izrain so line llial 111 niiponenl minerals are indisi iniruishable. The lit holoLrical characiers of these i-ocks, there- fore, are exactly those of the similar rocks described in the neitilibor- hooil of l''r;iiiklin (iiilch. on l''ortyniilc Creek, and the two formations may be correlated. Missiiiii Criik. — The main bramdi of Mission Creek iscallcd Amer- ican (feck, and Hows into Mission Creek only a short distaiic<' abo\e its mouth. On .American (feck, at a point about J miles above its .junction with Mission Creek, the black shales and I hin-becldcd liiiic- siones which outcrop at tlie imiiith of Missicui Creek are iimlerlain. in apparent unconformity, by dark-irrecn and dark-;jiiiy massive roi ks, which locall.v become slial,\ and which are evidently in the same belt as till' similar rocks which have .just been described aloni;' llic \iikon Mivcr above .Missiiui Creek. l'"roiii this |)oinl ahui^' the trail which leads lothc^'old diirjfinij;s on .Viiicrican Creek the chief rocd< exposed is dark j;ray or dark blue in color, locally u'reeiiish, ami apparent ly is { ii. lri8 GKOI.OOV OK THK YUKON (iOI.D hlSTKICT, ALASKA. l.„ ly MM iiiiprnv >lial.-, .'liMiiiiiriu' i"l-- slialy liincston.'s and lulTs. In n.i's vnrk aiv .v.-nwliMv /..iirs .,r sh.aiin^', al-mir which tiic iiiuo- slun.'.«.ha\vl.c.'iisili.-iri...l.i.i<«luciii-.silic.MMisliiiifst"iioaii(ljas|.croi.l. Tli.Tc aiv also, l.pcally. Inir -luarlzKcs, whicli ali)ii« slicar / s 1 sli^'hll.v iiirlai •|.1mis,..| an.l aiv cliaiactrii/.cl l)y llir .l.-v.-l- „|,„„.„i .,r i„ii>.M,vil.'. <»M ih.. up|MT pari of Ain.Ticaii Civck, at llic ,.|i.l<.nh.-liailshi.wiiniilh.Miia|Kl'i. \ I.VIl I. p. :!:!:). I h.- hmU is very massive an.! .laij^-iiivfii in <;,\nv. Il is -nicrally nmrh joiiiK-il, and al nn<- point \N licr.' llicM' Joinls uov ivniarkal)iy wi-ll developed the ehief si'l «asnearlv JKiiizonlal : at the same place w.. re \vell-develoi)i'd sliear /ones with a'striiceor N. :■< K. and a dip of :r> XW. Alon^ these sheai' zones \eiMsof .(uartzand cah-ite jiaiiillel with the sliearinyr liav<' been formed. 'I'hese Veins often contain e,>pper anhic, which clian;;e loeally into black shali-s, ami which will be described later, is succee<|ed by massixc dark-blue and dark-^rreen rock, weatheriui; red. and therclor iiispicinins from a distain-c. This red eoloi- from weatherinir is characteristic of the rocks of the liampart series, b(>lni; due to the oxidation of the abundant' iron, which in the pi'oto\istly surface Mows. These diabases ehan;.'e to waterlaid lull's, whose materials are plainly derived from (he duibase; and these tii'Ts become ;,'lauconitic and calcareous, sometimes conlainiiif; traces of or^^anic remains, and so pass into impure and .sandy limestiuics. \h in the rocks of this same series from other localities, the typical tulT has il j^roundnia.ss consisting' larj;-ely of serpentine and other indistin- guishable components, which incloses fre(|uent fnijfinents of olivine, auu;ite, and feldspar. Till-; KAMl'AKl SKKlKf*. 159 1 On Hinh Ciiil;. — On llii' Hail wliicli Icails to ilic ;,'i)l(| (liK;riii)r« from Circle ( ilv, at tin- |(i(iiil where it ercis>es liireli ( HM-k at I lie 'l"\Vel\ ellllle ( aelie, lliere i> exposed ill olllern|( a 1 \ |iieal eof (lie Kaiiipart series. 'This was ilie only oiileiop noiieeil aloiiK liere, the loek in ;;eiieial liein;; eoneealeil Itv gravels. Furl Ihiiiiliii III Mi/iKiok rc(,/,-. — Melow Cirele Cily Ihe ^■llko|| tlnws for .several limiilreil miles lliroiiuli a piMl'eeilv Hal re^rjon. i-overeil l>v sills and ;;ra\<'ls wliieli are mostly of I'leisloeene a^e aiin-like eliannel throiiudi a ranue of low mountains wliieli lie lietweeii this jioiiil and the .jiiiie- tion of the ^'nkon with the 'ranaiia. This portion of the \ ukoii valles IS called liy the name of the •' Lower Uamparts." The lirst lock found on i cropping' at the end of t he I'lais Jiist alio\ c Fort llanilin has the same peculiar lilliolo;;ical characti'is as the rocks of the localities already descrilied. |''rom this point similar rocks are exposeil coiiiiinioiisly aloii^ th<' \'nki'ii for iiearl\ loii miles, as far as the lieiid in the river alio\e the .jnnction with liivss ( reek, where this .series is overlain liy con;,doinerales, sandstones, ami ;,'rits, wliiidi are made up lar;iely of pidililes and. smaller fra^inents derived from the nnilerlyin^- ro(df contact iiheiiomena bet ween t liese shi'cts and the ad.jacent sediments, as well as the nature of the sediments tlii'iii- selves, jioints to tin ncliision that the sheets were surface (lows. On careful study it is found that the rocks const it lit in;; the transition between the typical iiiiieoiis rock anil llio typical sedinientaries are really lull's of varying; texture, which are derived from the minerals of the iliabase, the coarsest lieiii;r made up of lar;re framiielits, so 1 hat it is with dilliciilty distiii-;:uislied from the unaltered i;;iieoiis rock in the'tield, while from this coarse rock there are irradat ions depending' upon the comnilniitioii of tlii' component materials down to very line- c 4 i- MO (JI'.ol.DdV or TIIK YIKON liOl.h iii-Ti;ici-, ai..\>ka. ^rn.iii.Ml lulls iiiKl ai-ill,i is n.rks. in vvhirli llir liMi:mriils jiiv so SlMilllaslnlHMil.listill^MlisllMl.l.'. AI..III: I ll is pM H nil Iw li \ .T I ll.' IMCSl • •uiiiiiion vnrk iM-si.lcs I riir .liiilms.' is ,1 iiiiissiv... iliirk-jrivcii. I liiliii- jriiiiiK'cl iiiir. liavinv' a liap-likt' apiM'aranrf. vnIm.s.' Inif naliiiv is (.I'lni IK.I (Irl.Tiiiinal.l.' rxccpt iiii-I.t tli<' iiiicinsc.p.'. In places I his 1 ni.-s liM.'f-rainrd aixl .'haimcs In a (larl<-y:nTii, smnnlli-mxtiiicd slai.'. whi.'h is nllni .•al.-nr s in /mi.'s. In I lirsc wati'rlai.l mcks irlaii.-niiii.- is alMiiKlaiii. aii«l nii aih'inlinn prnili s silirc.ms ami IVriii^'iiiniis 1-nrks, aiic to;;eilicr as In form shear /.ones, alonu' which there has often been si liei Heat ion and t he deposit inn of metallic sulphiilcs; and alnnt; crevices have been formed quart/ veins, a few of which arc very wide ami persistent and appear to contain ;;olil in small amount. /lihriiii MiiiiiKil,- ( '11 1 1: mill llii 'I'miiniii. — For b^ or Jii miles below .Mynook Creek I here milcrop at intervals coarse urceii diabase and the associated rotdisof the Kampart scries; and the hills a sliiu't ilis- tance from the river show ihe dark-red color which the rocks of this scries iissiime on o.xidation. IJclovv these rocks, and apparent lyovcr- l.viiii; them with approximately I he same strike ami dip. ciuiie liiiie- stoiies, H:ray, litlioL;rapliic, a'ld often rarbniiai'cniis. jissnciateil Villi shales. 'I'hese shales cairv indistincl plant remains which sii^rLtesl . I I upriiH I Tin; u AMTA ur skhiks. H!l I>i'\(iiiiiiii iij.'('. l''irifiii III' Jii inili-^ lii'luw ihi- |(liici' till' l:ii'iii imks ol'tlio Kainpai't si'iirt apilii apiirai'. In-iiiu' pr'nlialily hi'ciii;;lii up In a Can It, si lice III) rliaii;;)' in tlii' dip is appaii'iil. A I litis poiiil I Ih' sfiii's \h ('III liy ;;rfal ilil^rs iiT );raiiili> aii( 'I'l'i t iar.v inck^ I Ihti' ail' I'Xpiisi'il, a I'l'W mill's al>o\ I' I III' iiiniiiliur I In- Tanaiia. miili'il\ in;; 4'ali'ari'iiiis i|nai't/ili's, '\liii'li piiilialil,\ lirlnnu: In Iln- l-'miyiiiili' si-iii's; anrl. MK t'liaisi- I'la^ini'iilal ini-k. inadr up nf dialtasii* lid I'll lis, liavi' often Ix-cn nlisci'vcd, and rari'l.\ is ilii'ii- any cniitart |)lii'iiniiii-iia nr any lini' nf si'paiatinii liriwi'i-ii I In' dialiasi's and llii' lull's. Till' rnaisi' t nil's pass u:iadnaii\ inin lull's nf liniT iriain, and llii'si' in tiiiii inln linc-ti'M nii'd ^lay slali's, wliirli lii'cniiii' calfairniis, and sn pass into iiiipnii' liiiii'stniii's m- lii'i'nnii' I'ailiniiarrniis. i' liy its altcralinii tn .jaspi-rnids nf lirilliant rninrs— jrrccn, Innwn. n'd, and ,'j;iay. .laspi-i'nids alsn arisi- fnnii I In' di'pnsitinii nf xi'iinyi'iiniis silira in till' iiiipnri' liiiK'stniics liy wati'i' prrcnlal in;:' ainn.;; slii'.ii' /nni's. Snini' nf llic liniT-;:iaini'd fi'lilspal liii' i ks aii' alsn indiirali'd in llii- saiiii' niaiinci'. (HIht inrks wliirli alsn liavi' ni'aily llif sann' appi'jir- aiiri' arr i-liiclly liijlil-^riay in I'lilnr and appear In lie \ ery liiii'-iiiained silieeniis sedi liielit s nr liii\ aellliles. These lilie-irrained silieenns rneks ai'e till' lianlest rneks ill the fnrniat inn, and sn are innst pei'sisieiit in detrilal rneks wliieli are derivi'd Irniii the disinleLrral inn nf the rneks nf the lianiparl series; therefnre pelililes in the yniiiiLier n\ irlyiiif; cnli^flniiierates arc nl'tcii alninsl cxcliisix cly nf \ arienlnicd Jaspcrnids, (.•lierls, and nllier silieenns rneks. i , ( l.AsSiril AlliiN 111'- rill'', HiiCKS OK Till-: liAMIWRr SKUIKS, IHiilxifii . — The diabase iseveryw I ere reiiiaikably iiiiifnrin in appcar- aiiec and eninpnsilinii. It is ;;i'iici'ally dark-jtrceii in enlnr, with a IS iiK()[„ I'T ;! 11 _^ ICj (,1'iinrjN (iK THK MK"N (ii'lD hHTKIC I, Al. \SKA. I.-Mii.v viiiMiii; It. .1,1 III!.- or M.-.iilvii|ili.!inii'' I'- r.-itln-f .-...iim- .ind pflMllllliU . all'l -■"Mill llIK lii;> ;i IttliU'll'y liiWillil Jl iiiiipliynlir stnic- liiri'. 'I'lii- !fliN|iiirs iii 1lif C. lill'^l- I'll k ni-f li^'lit-^rnv ill folur, while tin- ii'si 111" till- niJiH'i-tils ail' "1 .1 i.'1'iH-iii I .Ijiik L'lf.'ii. >licri>?«M>|ii liM|.MT.\>iiiliii ii-iiiirt*Mi opiiitic, llio iiiiii' r.iis hi'iiii: wi'il < t'liil-i :i!r iil.iviMi-liiM' iv-tiilli/i'il Mii'l iiiirkiii!;. 'i'luM'ssi'iilial iiiiii- II 'I auiriti'. » iili cricii 111 licit (ii-tluK'lasf ami ili.ii- ia^'i' ^.•.•.•>.^(.ij.'s wliii-li iilii'ii lirctpiiic M'l-.v iiiipoiiaiil. af<> oliviiM'. ill', iiiii'.'iii-tili'. iliiiciiili'. 'iiiil lim iilili'inli'. ^i'i|Miiliiii'. t'lM'liiii . i''iii-i pyrili'. (»r tli.'M'ilii' nlivinc ix ahvays a |friiiiary niiiHTai, ami ilii> iiiairiii'lil'- ami il iiili' pntlialily iifarly nl vvay> ; i|iiarlz is suiiii-l iiiios priiiian ami w)iiicliiii.''«i\ iilciilly > mlaiy, wliilc I lii' ijilrili', "piil.ilr, Miial nilili'inli- !> iii'ail\ a'lwaxs ili'iivi'il I'niiii iii| p\ rill' M I'lii 111 ili'piiMl iipiiiitlii' lii'iiiiiipiisiliiiii til tlii'i'ssi a ('■iiisi itiii'iit iiiiiii'ials; till' II'' till' aii::ili', iiiiil till' vi'i'pi'iiliiH' ilMiall> rnmi llir ulis im', fn'i|iniil ly (''Mill till' aiiiii'i'. f,;/((M7:-«/'ii/"i.v' . -I Jiiail/.-ilialia'^i' I'in'i'is liniii llir l>|iiral mrk just, (Icscrilti'il only in till- im-ii'aM- i>l' priinarx i|iiaii/ tn Mirli a i|iiaiitily jis 111 fiiiiii .111 I'ssi'iilial I'lin-^titiiiiit 'i'lii> jrivi's tin- fork in ilif liainl Npi i-iini'ii a Ji^ihtiT iiiiii )i;rayisli i'hIoi Oh iliiihiisi . Tliis vaiii't\' is M'i'v ci.iimioii ami is \\v san a- till' iypical ilialiasi', cxrcpl that IIh' oliviiH- 'ii-^'oiih's an i">m'M- lial lliliiiTal. 'I'liiTi' is soiiH'liiiii's i li'iiililii'\ !ii\v,ilil a poroliN lit ir sitii.-inri'. ',>f(r(/7r-i(//c/)/( -i//'.Wi'i.s' . - in till' >iii;rli' 1 liiii M'i'tioii I'xaiiiilii'il Imtli ijiiail/ ami oli\ ini' witi' mi ainiiitlam as lo In- l■^s"lll la! niiiii'ials. w llill• tin• siriicl iiro o!' the loi-k \\asiilln'i'«isi' llu'saiiie as that ol' llironlinaiy lypi'. (Iiihhriiiil olirliii -iliiihiisi . -In a sinjli- s(H'riini'n pii-knl up in lli(> "lloal" on IliiiiliT Cri'i'k, \Nliirli i> mii' of tin' liranrlii's of Mynook ( ii'i'k, till cssi'iitial ronsiitiifiils an' aii;rilf. iliaila^'r. ami oliviiu'. ria^ioi'lasc is pi-i-si'iit in Muall anionnis, ami Ihi'i-i' is a ilcciili'il pii-ci- lilir sli'iirt III Till' oil villi' is ureal ly alti'inl to MTjit-nliiit' in 111 irons anil splii'riili'.ii' inassi's. 'Tln'ii' is a ii'iiiaikaliiy l.ii'i.'i' proport ion of iiH'tallii' siiipliiili's in till' rork, anions whirli aio laaii'.isiii', pyilli', cliali'opN rill', .'iinl pxrilioliti'. 'I'lirsi' siilplijili's, .jiiil;.'inu: i'loin tln-ir lialiit. ail' pi'olialilN' imliLi;<'noiis aiul primary. Tin pyrrliotiti' roii- laiiis a Ira I' ni>'ki 1, as drii' niiiii'il hy |)r. Siokcs. ol' Ilic Survey. S' i-jii iitiiii -tiiiY.i. Iiiili'i- iliis lii'ailini: are elasseu eertai.i rocks wliicli were c'lllccteil on 1 1ll' ^ nkon Uivcr almx c .Mission ;'rcek ami on Aiiicricaii (reek In the hainl spci-imcn they arc darl' -urceii, heaxy ami iiiassi\-c, « iili t he color ami e- tea sy feel of M'rpeiii inc. rmierllie lliicr iscopc llicy are seen to he liiaile up eliiel!'. .if selpenl ilie « llicll has no .-special .In let inc. In one of t he '>ei'iioits, liowcser, are Inokcn ami irrctrnlar trrains anil siiidls of ojix ine, »\hieli pass i'.io serpeni ine liy a process ol all era I ion; there are sinallcr frairiiieiits of plaLrioeiasc l'el(ls|iai'. ricsjijes t he -.erpeiit iiie in t he lirouiiilmass t hen ■!••• ehloiite w^. Till. KAMI'SKT MLKIES. ICS II! I' I iPllicI' '|i'Cii|ii|(iisi| imi |ilMi|iii-U. ,1111 1 oil I'll ;i I III III hi II I IiKILMii-l III' .11 II I tit III' I' ii'iiii ■>.\iili'>. \N Inch a I SI I :i|i|M'ai' In lii' i| iii|mi>ii mn iirinliii'is ;iiii| to lie iliTisi'd I'll nil till' >aiiii' MiiiiOi' iis llii' M'i'|n'iil iiii'. Itinliii.sif liiljs. — 'I'lii'M' riii'ks jirt' .sihih'I iim-'i I'uarsi' ;,'iaiiii'i| ami I'uii- tain anirular I'lau'iiii'iils nf i;,'inMiiis iin'k>. wliii'li ari'MTv imi ii'i'aMi- in llii' liaml h|ii'ciini'ii ; nlln-is an' liiii'-^iraini'il ur aplianilir. Tlii' I'lilm- is ilark-i:rc'<'ii to m-arly Mack. T'.i ■ lypicai mar^i' lull's ari' niaili' ii|i (if la;';;<' fravriiiciils nl' aiitrili-, iilis Im'. ami I'l'lilspar, all imiri' m lix> (I<>coiii)his'il wiilmiit iii'ilii: iln' Lrrniiiiilnia^.- is ll;ii'- yiaiiic'l, anil cunsisls lar;:«'ly of si-i |iiiii ini'. In aiiipilii'i- iNpi' iln* (.'roiimliiiass is iii'i'iluniiiianl ; il is a liin' iiiiiiniTV |iliiir\ sialliiii' iLri-'i''- };ati', lary:i'l\ k.'iiilinicami si'i|iciilinniis. In ihis triinimliiia^sari' many anun'ar nr siilian^rular I'lairnn'iils, suiih' uI' w liiili an' si'\ rial inclii's in Icii'^l li, ainl all' liitlil -rnlmril ami punnis in I lie liami spi'i'lmm. I in I it llic niicriisriipc siiiiH' lit" these l'ia;;iiiinls sfcni tn In- jjlassy, w liilr nl Iiits vary fniin iiiirrul'i'lsiiii' tn fmrly cnsialliiK'; in tin- I.iIIit i-m-i'IIh'v air apparcnllx iiiaih' up lartji'ly nf I'l-hlspar ami i-aliiii'. riii--i' Irai: ini'iils si'i'iii III ii'pii'si'iii I hi' irn 111 ml mass III' snmi' \ iilranir imk amh'- ,sitr, iir liasall . 'I'lii' liniT-ijraiiii'il liialiasir lull's lia\i' I'sM'nIiallv i In- -aim' iriuuml- ina'^'- as alrcailv imliil. « liifli I'unlaiiis lai'L."'. Iimki-n i'i_\ slals ul' aiiirili', liiii'iilili'inli-, i|nart/.. I'l'lilspar. ami aiM inulitr. In mii' l>ii'alii,\ almvc Ciirii'Citv- tliisdark-i^'ri'i'ii I iilV is spntlcil with many small, w liilc lii.iIiis 111" cah'ilf, wliirli nmliTtlii- inii'insi'iipi' slmw a tilirmis si riid iih' sinr p'stiiiy: iii';raiiii' miKin. In .-.niiii' n'' ihi-si' nicks, .ilsu, ;r|,'ii||.|,niii' li.is fiiinii'il aliiimlaiil l\ . The i|i iiipnsil inn nf this mineral In silica. I, \ pl- cillv clialccilniiic, nfiiii splicnilil ic. ami In |iyrilc nr siilcrilc. may often I Iisii\ I'll. Iiiili li , iiiiniilili liitl's. Those i'licks which are cleai'l.N' nf I llTaeciillS ori;.'in lull in «hicli the internal e\ii|enee is imi cniicliisix e as tn their ilcri\alinii from ilialiase are ela.s.seil simply as inlTs. They shnw ,i ;;railiial traiisitimi frniii the tnlTs which an' maije up i>( ili.ili.i^M. iletritiis, ami ililYer fnnii tlieiii ehiclly in llnir limr ;;raiii. In all these nicks are small ileliit.il fiairiiicnls. cni; stiiii; miistl\ of i|iiarl/ ami I'l'lilspai. cmlieilileil in a Unc-'^railieil, inicroeiyslallim'. clilnriiie ami serpent iiioiis ^I'oiiinlinass. ( liiii-shili .- 'I'lic llne-L:raiiiei| tiiO's pass ).'ra'liiall>' inin ilie c|;iy- hIiiIcs liy ih" 'iisappcarani f the lar^'er ildriial fra;:iiicnis riicse rocks \ai\' fi'oni liy;hl ;;rei'ii to nearly black in color, ami are smnnih- tcMiircil. snineiinies cum par.ii i M'ly massi\ c, nlicner li>s||i' m- sl.iiy. rmler the micnisenpe tlii'V ale seen In lie liiaile lip nf I Very line a;ri:rc;;ale kI tin\ ilctrital i|iiarl/ ;,'raiiis. with much kaolinic ami liiusciiN it ic, often calcarcniis ami carlhiii.iceniis, niatcrl.il. ('iirliiiiniii mis .sliili . Til » t.\ peilill'ils flnni the last i Ic-cril leil cji ielly ill the presence of aliiimlaiil cai'linii;i Us material, which Ki\e> a ilark-;rrccn nr iiearl.N' lilack color. The rock is )ri'iicrall> striiii;;ly li.imlcil or sl.ii \ . ,iiii| p\ rile is lieiieiallv |iri'seiii in Jariic ci \ .-i.tN. KJl (i|.lll,n(,^ .i| IHK VI KoN iH'li IH>TKlrT, ALASKA. I,,i.l>u,. .siiiiilsli.in . -On 111.' >.iiiili I'oilx Ml K..n\ iiillr CiTck mihI mi MMi.M.k ( ri'fk w.Tf iii>i.''l l»'- ill ilif Uaiiiimrf «.<'iii«. ■rhr.lrirltiil rriiym<'nl!.jir.' l.iip' ■><"'■ >'»->b cl.-ii-riiiiiiiil)l<', and tliiTc i^ iMPiiM.l.ial.li- i-alcilc. iiMiiill,\ |>r<>>«ciil a** a ituhmiI. Tilt' nicks ari' jri'a.X' 111' iri-i'i'ii in cnlnr ami ;;iaiiiilai- in i<'\iiiir. ThcN aii' inailo up n( ••liPM'ly «'oiii|iarli'il iriaiiiN ol" .|Mai-I/, plairiiii'lasr. ami orl IiucImhc. with ..llicr l.'ss-rn'.|ii«'nl ii.im'ial'>. Miii'li'il llii' ri'i(ls|iai' appears to lie Miii'iiM'lliir. •iilcriic. Tlic inli'isiiic- liciwccn I he ildrilal ;,'i'aiiis arc usually lillcil with I'alcitc. ami in ilii>calciic is ;;cm'rally cniisidcralilc plainly \cniii;cm)iis pyrilc in pcrtVci civslals. On Myiionk < reck. Iicsiilcs llic iron pyrilc is cniisiilcraliic clialcnpx rile, wliicli slains llie rock irrecn on (iviilal loll. This Lrrein stain uas roiiml liy hr. I lillcliraiKJ, ol the ^iirxcy, to lie a niixliircor caleile ami copper silicate. Two assa\s of rock cari'yiiiLr this copper pyrilc ucre niailc; one, liy I'rol'. ( . !•'.. Miinroc. ol' \\ashin;.'lon, ;ra\e no i.'olil oi' silxer: ami another, lp> l>. II. oiliccr. ol' Salt l.ake('ii>. i:a\c no irolil ami t wo-tom hs of an oil n f sil\ er |o i hr imi ; a ilill'crcnl sample tra\ e Mr. ( Ulicer one oiie-hiimlreilili of an ounce of l'oM .iiiiI no siher. I IK I III 11 1 1 nil slum . Inipnre liincsioiic is loll ml a I iiiici \ als I liroiiyli- oiil I he foi nial ion. Inn mil in LTieat ainoiinl These limestones are yeiier.illy dark-^ray or dark-liliic in coloi-, and are made up mosi ly of small ^rrainsol' crystal line calcitc. This ca lei te incloses del lit a I ^;rains of ijiiarl/, leldspar. and imleierininalilc dccoinposition products: it also soineliiiies contains earlHiiiaceoiis malerial and ;;laucoiiite, with secoi;dai\\ silica of I he clialccdoiiic or eryplocryslallilic \aiicly, and St Iar.\ lira in-. o||i\ rile and hciiiaiiti', so times pari ly altered to siilclile. /• nil -iiriiiiii il iinii rl-.ili , iir iiiirni'iihti . — This rock i-- I oil lid at \ arioii* poinis in the {{aiiipart series, in npaiat i\ el,\ thin licds .Mci.'a- scopicallx ll is liulil-y:recn and aplianilic. ami jiciicrally thin -ocdiled ; iiilcroscopicall.N it is seen In lie iiiailc up of vci'y siirdi, roiindi'd ilelri- lal grains of i|iiart/. eenicnled li> -econdary silica. There are also occasionally piocnt iiiusco\ itc. /inon. and kaolinic and I'criiiyinoua malerial. .///.s/" /o/i/. The Jaspcroids .ire rocks .(iiisisliiiy: chiclly of silica, p'nerally chalcetlonic or cr\ pio<'ryslalliiie. and ate plainly ilerixfij from (he silieilicatioii of other rocks. They arc loriiicil in \aiioiiM wa.\s. lull inalllriic .jaspcroiils the silica is secondary, ami inlidduceij sllltseiplelil to the dcpositi'ill of the rock. .\ii iiitercsliii;:aiid iinporlaiit variety is the iilaiieoiiit ic jaspemitl or taconile. such as h.is Ihch ilesciilicd li\ I lic' w liter as oi viirrin^' aluin- ilanll,\ in the iron-licariim i .cks of the Mcsalii I'lnyc in Miniicstpla. In lilt' rocks of the Uaiiiparl series ii also appears that the ylaiieoiiilic Till. KAMI'MM SKUIK.S. ii;:. liliifNliiiii'^ |i;i'»> mill ,iM>|iiTiiii|--, « liiill ,ili' I'lilnli'il nil. :;iciii. liiimn (ir ;;i;i_\ li,\ iimi in il> (lillVii'liI riil'iii>. ur iHT.isiniiallv li\ iii.ilii:;iiii"«i-. Of wliirli iiri' lii;lil-ui'i' V nr iiciiily while. ,i> a t("scs nl' liii> (•liaii;;i' aii' i'\arlly lliiix- vvlinli Iia\<' liiTii (loi'iilinl fill- III!' lai'iiiiiicN 111' Miiiii)->.oia. A I'oi-k i'\liiliil iiiu ^^<'ll I'll' liaiisiiiiiri lii'U\i>i'ii llic irlaiii'iiiiit ii' lliin' >|iili<' ami I Id- .ja>|M-i-oii| waM'nIli'i'li-il mi llic \ iikuii UIm r in i In' I.uvm'i |{iiiii|iai'l>. linn- in a I'lilV \va'«' inaili' ii|i inii--ll.\ nl' iT\ |ilnfi\ >lalliiii' ■•iiira. wliirli is rlialciMlnnii' in |ilaiT.s. w il li splii'iiilil ii- aL.'i,'i-i'Lial('s >liii\vin;.'ilaik imicm-x iinili'i' rinssnl liiciils. (ilaili-niiili- i> ahninlaiil in iiii'irnlar «rain> nf all -i/f.. ainl till- ili'riiiii|Hi>it inn 111' 111 is III i una I. rnnniiii.' clialrrilnMii- siiii-a ami iinii oxiijf. is M'cii in all its sla;.'is, jlic |irniess is thai nlisiMV cil li\ ijn' wiiii'riii tin- iiii'ks of llir .Mcsalii ir m iaii:,'r. Tliis i|i-i'iiin|>iisiiiiin aciininis Im- I lii' iay;i^ril mil linrs nl' I lir ;.'iainsnr irlanrmiili'. 'I'lir iioii is ilaik-ii-il, ap|iai('iil l,\ uclii'iniis limnal ili'. ami nrriiis i'\ ii\ ■.^ lirri'. llimiirli il isi-niisiili'ialily Irss in animinl I lian I In' Lilain-nnili'. ii s|iii\v> a Ii'IkIi'Iii'V In arcinniilali' in iri't'irnlai' rhiinps. ( ali'ilr in I'l'i'ipiriil rair;;<'ii areas is ri'siilnal. Iii'in^ I'lii'mai'lii'il mi li\ ri'> ploi'i-ystalliiii' silii-a. wliii'li is i'\ iiji'iil 1\ ri'plai'in;; il. Tlii' siliia ini'iiis also in isn lali'il LTiaiiis spiinklcil I lirmiu'lmiii I lir I'ali'iif. 'riii'si' isnjaiiil '_Mains an- liki'wisi' i'\ iili'iii ly s nilar\ ami an- ii'plariii^' ll iili-iii'. iliis Iti'iiiL' III' llii' iiinst iii'ilinai'.x pliriimm-na >>( i|ii> silieilii-al imi nl' iinii'simii'. as nlis('i\ I'll li\ I li.' w lili':- in I he irnks nl' .\spi'ii. ( nlmailn.' Till' ii'siiliial I'ali'ili' is iil'li'ii 111 a ;;ri'i'nisli liliii' rnlm-. wlin-h is smiif- linii's liai'i'l.\ pi'ii'C'pi ililt' ami a^iain v<'i'\ ilci-p. 'I'lii'ii' is I'l'i'ipicnily n ;r|'ailual I lallsil imi I'lnni lllis fnlm- In I lie ilct-p Im'iiW llisli-i.'1'ccM of till- jjlaiii'niiiii'. Till' u'l'i'i'iiisli-liln Im- siiu:;i<'sis niaiiiraiii'si', an I'icim'iii ol'ti'li ni'i'iii ;'iiiv' in siiiail aiiiminl in '^lam'miiii'. iiniii wliii'li il iiia> Iia\i' I II si-paiali-il iluriiiLT lln' ili'i'ninpnsil imi nl' this niiiii'ial: ami a clii'iniral lest li,\ l>i'. Ililli'lnaml. nl llii' Sni'M'y. slmwcil a I lai-- if inaiiLiaiii'sc in llii'inck siilliricnl In ai'rminl I'm' I hi' I'nImiiiL:. Ill lllis lliiii si'i'limi alsn all- scmi ni':;anii- iriiiaiiis nl I'miipliialcil !>t riii-l nil'. Tlif siniri nil' is liriiii;:hi inin prmiiim'iii'i' li\ i hr ini'irasnl aimiinil of ^laiii'oiiiii' ami imii liiin.'(l llir.iii-l I Willi i|.. ■,.! .|ci.|.l\ thill llir P"-k i- ii|ph;iiiili<- .'Mil iiliclfi- Itif iiiicni- iiii'i'ii ,iii'l n •I P l«.|>clo|il li;l\ IIIL iiiiK' >iniiiiin' lis lliutr • IfsclllH.I illlilV.-, Willi llu- cM-rplinll 111 lllr n".i< I ll.l I ^'lilll lilf JIIkI cjiliMii', jiK' l'ifi|in'iii ill lli>' ripi'ks ..r ihi' lkjiiii|iarl s.th's. ami liv ira- .sMii ..r lli.'ii •.lllHTior li.i|illir>s iirr iimsl .<' iiM'ks. riii'V an- imiilf Up «-,ssciiiiall> "T r*ili<-ii. wliii'li \arii- I'li'iii |«lif i>slalliiii' I" liiirly i-rv |ilM.i\sialliiic, aiKJ Ih'cuim.s iiCli'ii cliiilri'ilDiiii-, lilnoiis. nr splicni- liiic W'liiTo 111 i^iiial inck cuiiiaiiiol iiiipiiiil ii'>. ilii'sr iiviirrally I'l'iiiaiii ill ill- .ias|ii'i-cii(l. MP llial in llif xilira is I iic|iii'iil ly I'miiikI i-ai'iMPiiai'i'iPiis ami i'la\<'v iiialiTial. ,S. Itisl,. ■/.; Ajipii:^ >li<'ai /mii'S llii' i'>p('k^> i>l' iIh' l{aiii|pai°l •iiiN ail' >i'ii liiiii's >li;.'liil\ iiiclaiiinrpliiPM'il ami iirw iiiiiii-nils aro I III AiiiiTii-iiii tifi'k ami "ill ' N iiknn |{i\cr alxivc .Mis- lll'llllllD'l Niiiii (I k vvric i'iill<-<-ii-ii|i'ralil)> luiiriiialiiii' am •piiliilt ami specular iniii is pri'si'iil in pirlcci civsials. I I KIN IN llli: KAMI'VIM sKltir.s. Till' ripcks ipI I lir /{iiiiipaii siiii's arc I'lil i)i'iiiimll\ liy lalcr iiilril- .siiills. TIh' IIiip>.| ' lri|iicMl ilikr nirk is mallil"'. wlliili (ici'iirs in iiiiniciisr liipilii-. ill 111' l.iiwci- Uaiiipai'ls hflnw M\ muik ( ri't'k. I'iki'H ipI' yiiiiiiii-piiipliyr.'i ami >>( liuf puipliyry. wliidi arc pinlialdy clnscly i'i>laii-i| III I ween ( hirki-n ('■'•■rk all)! Ill)- Soitli |''iii'k III' l-'iirtyiiiilf (ii-i'k: anil in tin' saino vicinil\' ai'i- larir'- piiki'soC (iiiii'-i/.-ilinritoiir yranilf. wliii-li is pntlialily iMiiiin'iifd ;;ciii'i ii'iilly with llic liiifi i;i'aiiii'il nirks. Dikes iif aplilu Well' imii'il nil Anii'i'ii-aii (ii'ik ami ai ilic <'ii( tlic ^°llkllll l''latH aliiiM' I'lPi I ilainliii: mi Aiiii'iii'iili ( reck is alsii a small iliki' nl' altered I'lpck. vvliieli appears lip lie iiiii'a laiiipiipphyre. I'liMHM,. <>»iii^ III ilie inasHivc iiaiiii'e ipj' I lie rocks ul I he Itainpart scricn the licilijin^ is p'liei'ally mil iliseerniltlc iirean mil ili-^iini;!!! .heil fi'iiMi the jiiiiiiiii^: ami slicarini.'. .Imljiiiiu I'nnii ihe emlerlx 'iv.r ami ii\erl\ iiiy riiniiiPi iuiis. liii\M\ er. this series iiiiisl iia\e ' 'eii i niisider- alil>' I'lililed, altliipiiuli mil iiileiiscly. Sea'' l'''irl lliiiiiliii an pppielii- iiity was riiiliid til " I'..: dip. -'II N'W. I''iiiiher dipw IP ihe ri\cr. in ilie UaniparlM, strike ill' \. -jr, I-; a ml a iiip if |i' >K. Well' nil' III tll(« Kfei'ii slates 111 Mymii.k (reel, a '.Irikenl' \. In K. and a dip ul" MO' •I'l HH ) Tin; UVMrAliT SKI.'IKS. >!•'.. «cli' iiiitnl. 'riit'M' iiliscrv ill iciiis. t.iUi'ii liii;il Iii-i- « illi tin- .tlli- lilili- i>( tin- liiiii'Hliiiii'> ami >lialc» « liirh ".iiitimmI iIh- U.iiii|iai'; -iTics HiiiiH' disliilH'i' lii'liiw MviicHik (n-ck. serin ii> slmu ihal tin- iMi'ks liaxi' n feudal rmitlicasl >liiki' ami a sdiii lica-.! iicai'l> litii'i/iiiiial. wliilc aiiollit'i' >ii'jki-« \. ii"! K. aiinii; '<>< SW.. Were nulcil. AIm>\<' IIi'>s Crei'k. jniiil iiitr w il Ii a >i nki- nf N. jn |.; ami a ilip III' il"i SI!, was mdi'il. < 'n M\ ninik ( rt-rk at (lilVci-ciil Im-ali- lio, iiiily a mile "If su a pari, was wen juintiii;; w iili I lie fullnw niu alii- liiilcs: slriki' N. s"p !•"... >lip sii SK.; sirjke N. In !■'... ilip s" SK.; Nlriko N. 'la W. ilip '.'n N'l-'.. 'I'Ih' jninis at llu'sc (lilTereeii plaei-s in widely srpai'iilt'd pailsuj' ilie iCampa;! series show no iiiiirnrmii v in attitude and Hii^(:;<>st im edmiriMii cause. slII.AI: /(INKS. The shear /.nties are inliniali'iv euniieeled «;lli llie juiiits, and are, ill lael. esselil iaily a series 111 parallel Juinls, se! \ii\ I'liise liiueliier, alon^ wlliell tlieri' has lieell s.iiiie imiNenielll III' sllppini: 111 the iiH-ks. prndiK-iiit; jiieal alieijiiiim. The inek aliinu' the shear /uiie is jien- craii.N sninewlial eriished i>r sirelelied. and nielaimirphie ini'ii'rals are siiniel ilnes devejiipeil nil a Hiiiall seille. Mule Inipiirlalil ehaii;;e>are \vriiii;;lii li\ Ihe ill! riidiietion <>r xemip'iiiiiis inalerials li\ waters whii-Ii iind eniiM'tiient I'haiinels almit.' these /nnes. IJy the aeiimi cif iliese waters tile n-ek is iri'iicrally mure or less silieitjed. and ihere isoften liepiisiliiin 111' iiM'lallie sulphides. vi;iNs. N'eiiis iif ipiarl/ and eiilfile are Ireipieiitly fmi id. esp«Mially alonu Hliear /.lines, where Ihey are t'nrmed ill llle ere\ iees let'l 1>\ Ihe nni\e- lllellls ill Ihe Inek. Tin V ale i;elierall> linlirnkeli. sinee llii'yhaM' flirnied Slllisei|llelll In llle shearing:. Oil l.iltle MviiiHik ( reek a vein of pure w hile i|uaii/ i; iVei wide w as nnled, wliieli appeared to Im- per- sisleiit and 'Nliieh was said In \ield L'nid III! paiiiiini;, alllmnudi niiiii> appeared in nlllr'rn|i. \I1K 111- I hi: K WlI'Vlil sKKlKs I tn l''nrt \ mile ( reek near {''raiiklln < liileh llieUampari meks appear Ik nvi'i'lii' iiiniiodialidy ihe |''iiri\ mile series. This is the niily plai'i' where the JKIietinll nf llle Uainpai't series with the illiderl\i ".r I'nrnia- tiolls has lieell )iiisel'\eii. Iielnw .Mviiiink (reek the itH'ks nl' .hJH 1(!K (ii'.oLiMiN or TiiF- vi'KoN (;in.i) nisi'Kirr, ai.aska. scl-ii". ,i|i|ir;ir Ici Im- i|i|i'c|I>- ini'll:iill li.\ rnif-;.'r;iilicc|, ciIIiMI r,i rliollJl- II'. liiiir-idii.'s ,iimI -1i,iI''>. wliic-li iMirv |ilaiii i<'Mi,iiii> >lly:^r^•^*l iiiu I»i'\ci|li;iri ML'"' 'Ml llli\llkilll iili,i\r ( ilcli- ( il\ till' l{illn|l,l|-| liil'ks air -ucc Ii'il li\ |iii)liiil>l\ ip\ i-ilv iiiir liiiii'>liiiics ami .|iali'> >iiiiilai' In lliiiM' jii^l iiii'iil loiic'il. In sui I' llii'M' liiiii'slipin'.-. all' chaiartciiNl ic ( ailicpiiili'i-nii-. IiisnIU \\ ,. max iliiii'lnii- cuiiiIimIc thai tiif iiifk> ul' lliis M'iii-> arv vi)iiriL:i r I liaii llii' I'ml \ iiiilc sciio ainl njili'i- 1 liaii I lie olJH'i' I'liiiiial i('ii> vv liiili "ill lie iIi'mtIImmI. Tiir iiili'iiial si nirl iiit" ol' fill' nicks llii'iiisi'lvrs >liin\s ''Ifailv thai liii-.\ aii' yiiim<,'ri- lliaii 1ln' Furl villi Ic Idrks, I'lir i'\ clI \\ lull I lie 1 Wn st-rics orclir ill I lie same Iculiin, as CHI III!' Suiilli l''iirk III' I'lirl \ iiiili' ( ffck. tin' I'mlyiiiili' scries vjiuws the result-. Ill iiicat cli-l iiiiiaiicc^. wliicli liaxciinl atVcclccl the rucks III' the |{aiii[iai'i series, ami » liieli ilierelore i iirrcil prcx imis tu I heir ulher liaml. the I'lniiiat imis « liich will he cuiisiiiereil later shii« suine- whal los ilynaniic iii>i iirliance than ilu the Kaiiipart rucks. Ill a s|iiciiiii'n liiiiii ilie lfaiii|iart series lielnw Mymiok (leek, mi the ^ llkmi. sectimis 111' iiii'anic liniljcs x\ clc miliceil ill Ihill scellctll, which «iic iilentiHeil by Ml. liaslil'mil I >ean. ul' ( iiliiiiiliia < '(illcire, as lisli teeth, lint no iiimc >|ici-ilic ilelcnninal imi i-aii lie iiiaile. 'I'liese ale the miU I'lissil reiiiain-. Imiiiil. Kl iiNiiMli tMIMiKTANCK ■j'lic rucks ill' this series .nc charactcri/eil tliiuiinjiuiit liy ureal liasiciiN. The ilialiases cmitaiii a laiu'e |iru|Mirl imi uT iiliu^eiimiN siil|ihii|es. am! ul iruii ami uihci metals as cuiii|imiciit cleit:eiils uf aiiiiilc. uli\ inc. ami uther hisilicaics. In the lulls, which make up a lame prupuriimi ul the rucks, these iiialerials arc sc|iaralcil ami leii- ileied espcci.illv lialilc til I Icciiin pi islt lull : al'tcrwaril I he re irraii;;e- iient 111' the cmiipuiieiit clciiieiits I'lilluws Hat iirall.x . ami Ilu cunceli- Iratimi lit the metals in I'av m. l>le lucalil ies must lie luoked I'ui-. Siidi lucalities are alVmileil l>\ shear /mies. which may ruriii chaniiels I'ur walers licarini; mei.illie sulniiuiis ilcri\ci| I r Ilie ilccmiipuseil ilia- liases ,'inil t nil's, ami aloni; which these metals ma.\ lie ilepusileij iimlci pruper cumliiimis. .Man.v ul these iiiiiierali/.cil shear /.mics '111 \V II Hull. Ill iwi;. ri.pMil.il Am .lnui- s,i . thir.l ~..i-i,.. V.-l ,\"I.V. p '.m. ilinlliu,, ■■.juHt iil>..\ III. Kiiminii u. )»Oilil.H ,1 Xliimiiii hnii'Hi..n.. »iili it. .Imm. icrMir ii.««iK Nc, imilirr iiic'iitioii I. iimclc Thf iB-l.l.l.-s fcfi.fi-iMl I., Ilia) hiivi' Ibcii derived ii t|„. Itaiii|>iiri .■■i-|i.,. fcrlhc-s,. III'.' the iiiily r.n'le. c'xii.i,i.il ul,,!,,; tlic > iikicii 111 11)1' I.H'ulity name it .Micnc tlil-. tin- Hic'i llc.w. l..r wvral Imiiclr.'il inii, s ilii'..iiuli .|,'ii.,.it. .,| '.ili. win, i,.„' ,„' ,„, , x .„||,'|',,|,. Intel Iciulclc'cl with the'..- Milt, arc ..elll.'llllie., untVc'l-e M'hi. h ar.'. h..tt'l'\ Cr llll.cle' up ,l||||e»t C'Xi 111 ■lllcly eirillllU'l.! IM'1,1,1,.'. rilC cl.'I'llUli r the' | i.'l it lie llli'll t |e ,I1.'C | liV Hall Im t llC'I'de ,|-,. pfe ill ttlily licit fi'ciiii thc'cc- (ji'iiv. I- aiicl wliilc tlii' nicagiiii.'.. .,f tlie- liirin i- .in li thai ii..eiiii. c'lci.l..Ile'UIl li-sarc'lvcll'llVlM (!'. j V.'l.ccllt'lklilHil t,i(tl'tlllM' witli the ..vide- all c-llcl V lllcilluht fc.iMai'.l t.. .tieewilini the H,'iiii|cuil -c'Hc- is 'ilelc'i Iliaii Ihc De'veehinn unci I'iir a^iv-. ^Imw ,,\\\\ iiiiii|i.iiiin\ il\ iiiNi;;iiiti<-aiil aiiiiiiinl^ ol' i^nlil .iinl ■•IKi'i': in iIh' 11111111'. huwiv ir. |)rcililiil>li' "Tc (IcpMsils iiiiiN \i'i\ liUi'ly !»• rciiiinl i'i;i:\ icii s \(ii|.>. Mr. I{. it. Mc( iinncll makes ijiciiiidii of ili|., -.itIi's ji> tollnw-. in siimiiijii'i/.iii;r 'III' cr^ >ialliiic' ■-i'lii>i> \vi>si di'ihi' Kuc^ky Muiiniain-- .Miiiii; till' riisli'iii imIki' nl' llic (•ry?t iilliTcd viilimiii- rock*. Tln' must iiiipcirluiit variety i» a .-ilii'arcd ami alti'icil uri'eiiisli (|nart/.iwi' srliist. With tlii-. ari' iiss(Kiato |iiiiiils almii; 1 he l.i'Wis KJNcr ailiiNC its jdlicl jiill Willi till' I'i'lly. ( cil mill:; llic Icic'ks ;|ln|l;^ the I.i'Wcs Ileal llie jiiiietiiin with llie jiiv; SalllKPli l{l\c|-. he urili's: FrDHi the few e.\iiiisurt's which ec( nr cm that |cart cit the Lewes whic h cats across the Seininow Mills the rani{c> wcnild apiii^ar tec he ocniiicisi'il ccf ({ri'eiiish. altered voU-anic rcuks, prolialily diaha.si'. iiilerliedded with ;.'ray 01 whitish mar llie. Hcicks icf this character life those which have siipiilied the iicilc'rial tor the cccn:;li)mera(es clescrilii'd licl'iire c)). IKdii. ancl are evidc'iitiv iiinch cc'.chr lican these and clcmhlless refeialile to the Paleozoic . THE TAHKANUIT SKRIKS I'KKI.IMlNAin s|A jKMIAr. rinler llie iiaiiie Talikaiicjil series lias liec>n elassiiiod .1 scTio cil while cir ;rray liinesloiies alleriial iiiLr uilli imiIichi.icichis slijijo aiicl MillM'l lilies willl ecii|e;lciinelale-. 'I'llis clireellv iiverlic's the |{ain|iail .series ami IIIHlellie^ I lie .Missinli (reek series, wli ieli will lie cleseli liec | I; ler. Ill this scries have been rmiml e;i((Ml Ipiiei- < atdiiitiileroiis I'cis- ,sils ami |ilaiil rciiiaiiis w liiidi ace picdtaldy nl' l>e\ cmiaii .'ii.re. lint llie llniils 111' iieiilciLrieal 1 iiiie as^ietii>il ici ii in litis idassilieal imi are mil illlelnleil Ici he clelliiile The name lallkallilil is taken rniin the 'lalikaiiilil |{i\er. uliicdi etilels lli.- \ iikini m>arllie jnealilx where rplicr ( ailiciiiileniiis |'ci>-.iU arc ' iitml in u liile cm ysl a lli tie lita>fM>»llf!s. hlsTlillU TIciS Wji c,|:\|,|; \|. iMirx IMI'lliiN. ii\ nil-, ^l isccs Miccvi, c 111' ; 1 ■ rrv. Al llic' imiiilli ccT Missiciii r k are licijcl eliiVs c-cniNi^i in- cd' lila(d< NJiales Willi thitl'lli clileil sainlsliines miil liniesl.nies. uhieli will lie ileselilieii as llie .Missinli (reek series. These are civerlaili ralllier I .\tcic. Il.-pl 11...' Kill lll-t Scii-\..\ rmiii.l.i. Isss su. iic.«- «..n.'- Vc.l IV.]. |:||i 'A:ili Hc'i.t II. ."I N..' Ili-I Scii-v..\ c'liim.lci |ssT ««, iievv- ....i-i,.,. \',.| III I'liri 1 i. IMIl ^'! i ! \ 170 (ir.Mi.iM.v i)\- iiii; MKiiN (iui.n nisi kki, ai.vska. (low II liy lii'jixy ripiiu'liiiiicralf*. sluilfs. iiii'l >iiii. Tin' iiiiiIitIn ill!,' -.lialN iiM'ks allfiiiali' in liainK^hli ll \ i'il\ iiiir ruii- ;,'liiiiicialir rciiiiialiuii iicmiIn In I ln' 'ralikiiiiilil l{i\<'i'. wlicii' aiiulliiT fill iiialini ii>i>l iiiir 111' lna\ \ lM(l-.iir |iiiir w liilr it\ >lalliiii' liiiii'>li(iic, "I'al lii'iiiiv' .\ I'llii^v nil i'\ jiipxil Miilai'i's, I'liiiics ill. Tlii'M' « liili' (Mvsialliiic liiiir>liiiirs i'liaii;.'c iiii" ;,'i'a.\ , I liiiilicililcil liiiii'>tiiiii-s, ami alli'i'lialt' " illi I mm Is nf sliali'sainl r(iii;rl(MiiiTalc«,. 'I'lin rnii;.'|uiiifrat<'s riiiitaiii pflililrs iiC },'i'ay. «liili'. lilark, ami cspiTialiy fiici'ii c'lifil. « liicli is si Ml i la r to Ilia I nhscrv nl in I lit- |{aiii|iai't rucks, ami sii si|i.'L.'c>l> sils eolleeleil Were iilelllilieil as ( ailiiinil'i'iiiiis liy Mr. ( liarle-. Silnieherl. uliu iiiade ilio rnlliiwinji IT|»iirI, aililressei! In llie ! >i reel iir : In roKiiril Im 111!' fos-iils si'iit tn im- liy Mr. .1. I",. S|iiirr, aii'l (nllicleil 1j\ lii- imrty iin till' YiikdM Kiver aliiivi' t ircle ( 'ity. .\l;i-akal>ly Cai liiinifiruns. iiml ^-iin r iin rharailerislic Lnwir I'arlion- it'iToiis njH'cics lire iiicsent i infer I his fatnia to he nf I'lpi r < arhiiiiifi'roii.s nu>: This iiillectii'ii nlsii inilieated ihai the Yiikeii i rirli'inifenms is nmri' chisely ri'lateil In the N'evaila l'|i|iir < 'arliniiifirniis than infither the < 'alifnniia or Min- sissijiiii Valley faunas. Tlu' Viiknii, Xevaihi. an 1 Mississi|i|ii faunas ii|i)ii'iir to have iiinre s|iei-ies in coniniiin tii.in any of tln»e with that nf Northern Ciiliforniii. The fnllnwinif is a li-t nf the species; .\ni|ile.\n-'r .Vjipareiilly r-'laled tn \. /aphieniilmniis. I'riKliieliis niiillisirialns Meek. Proiliiriiis seinirelienlalns Marliii. Priiiln. tiis piinetatiisvariii\ I*roilu(tiis hin;.Mspiiiiis Siw. I hy, Prnilii.tMs Inimisiiinns Siwerhj .■ r'rn.iiietiis like Imoneiisis. lint nineli hlrijer, ('{. l\ iimlaliis nefraneo. Spirifir n. »p. It ha,sUsnrares| nlalinnsliipin S. senliiniis Mirk. Init iliffcrs in havin^,' more jJlcitioiis arranK'il in ilistincl Iniiidlr. Avii'iihilxfteii s{>, uiiilot. Tlicsc CarlMHiii'cfttns nicks arc >nciitl.\ Iml mil liiicii.scly I'dlilcd, liii« pii<'aliiiiis Ileitis; 111" aliiiiil (lie same ili>;;icc III' iiiiciisiiy as III llic iixcr- InIii;; ciiiie|,iiiicraies ami shales lictwccii llie TahkaiHlil Hivcr and Mi.ssinll Click. Tile I'lissil plaills lliilll llicseii\cr|,t |( n ijlUgliiliiciUlcH '*«"'"ii I" I'l'- '•>'• >''ii">- ill Hie Kueciii' pr|'iiii|. illlll i|| ii nj|HU s I tli|| Hut imisi iif ilic rohiiiii; whicli lias alVccicil In iieiiily I ic si|iiii> ilcirrco all the rdriiialiiiiis riuin ih,. K ,„. „s far i|ii»|| j|s |j|i< I iliiliill- ircriMis wasci)ihparali\cl.\ icecni—eeriaiiily |HiKl-|*;m'Mll»'. '\'\i\H I'll (■ I'lusidii rccci\es siippiiri lr ilic facl tlialllic lii|i(iiihili|i> l|llni|tr|l. (Mil ililsdistrici sliiiwsil vci'y ylusc ivlalioii lu i|ic sliiieii|ii.. In siiintt Ml Ull I 1 iiir. lAiiKANnrr si'.iiii> |iliHTS f I'lK'ks nil llii- ^ iiUiiii iiiar till' riihk.'iiiilil ItJM'i. iti' ilii spill \\ Ih'It I III' I'li^sils VMTi' i-iilli'i'li-)|. A liiiijul liaiiil 111' « hill' i'i\ -.liil liiir liiiirsliiiii' niakt's llir st rilcliirt' ciiiisiiii-iHuiv rrmii a ili*laiii'i>. ami I III' I'lililiii^' lull I ail antii'liiii' ami >viii'liiii' i- hIisitx alili' In i ln' jiiii iiri'. il is alsii si'i'ii thai llir aniii'liiii I'ui'iiis a lilll ami iIh' sviii-liiii' a val- ley, I in- 11 III lis 111' 1 1 11 'SI' 1i)|)(ij;ra|iliii' Tea In res em res|iiiii,||ii;; el.i>el\ in tllC limits III' till' I'nills. Ill this ea-e lllele ha> lleell lln | il'ni'i ill ||i | ein- hIiiII silli-e till' I'niilili;;. Iiclnw the 'ralikaiiilit Uiver Ilien iiie in ealeaiemis ami earlm- IIIH'enlls shilli'S ami t llin-liiddi'il lillieslnlles, uliieli ale |iiiilialil \ In In- assi;riieil In the saint' si'rii"> as 'he rneks illimeiliali'lv lielnw Missinii (leek. 'I'lli'si' rucks enlltilPle ii.lleln|i|iili:.' ainli;; t he ri\ el . allillial iliu' ill liamis «ilh I he enliiiinliierales. samlslnlies, ami ;riil'> lielnllLrili;,' in the series which has lieeli linteil as nxeriyiii^ the shales lielweeii Mis- sion (reck ami the Tahkamlit JiiM'i', as I'ai' as the .iiiiietinii nf the Cliarlic Hiver with the Viikmi. Near this pnint there cmiie in ;rrav ami ilark-liliit' liiiieslniies nl' ilistiiiclly nide" ap|iearaiice: ilie-.e are soiiiclinii's (lark-lilue nr ilaik-;rra> ami enarsely crysialline. Inii are usually very !iiii'-y:raiiieil nr aphaiiiiie ami iira.\ nr iieailx lilack. the cnlnr lieilll, line lar;;i'ly tn the presence nl' ea rlinliacenUs inalei ial. 'I' he cai'linliaecnlis li liiestnlies lieciilne t hili-lieilileil ami pa^>> ililn caleareniis ami carliiiliaceniis shales. The natural irra> nr lilaek cnlm- nl' ihi' I'rcsii ruck ln'cnint's in places yellnw-lirnwii rrniii iriiii riisi, whieh is (Icrivi'il rrnin the (|i'cnni|insitinll nl' pyrile; this pyrile is ilisseininateil in t iiiy crystals nr nut-like enncrei inns, 'i'liesc rneks miii-mp I'nr .in nr III miles all >li;,M he N'llk I a lieliiw Charlie |{i\ er. .^1 I he eastern end 111' the cNpnsure iinpeirecl I'lissi Is were I'niind ill rather inassi\e ^'lay lillli'Stnlle, lillt llnlie '^iind elinl|e;h I'nr idelit ilieal inn . Snme .IHiir li>llt IS nr Jll miles iieliiw the niniilh nf Mymiiik (reek, nil the ^'ukiili. the rucks nl' I he IJ.iniparl series are siieceeded li\ ;;iay lillm. jrr.iphie liniestnne, u hicli ill places lias I he appearance nf li,i\ ini: 1 n fnssilil'crnus; liiit the inck has liecii sn kMcaded liy d,\ iiaiiiic act imi that tlie I'nssils arc iini ^ni/alilc 'I' he re are niiiiiy sean.-^ nf iin\ ac- illllc nr liiic-irrained ipiart/iti . which slinw liy their separ.ilinn and breccia I inn the ninMiiiciiis w hi. 'h lia\c taken pl.ice. (Sec li::. 'i. p. I Tu'. ) Tiicse liineslnlles alleriiale W il 11 carlinlia lis slates, u hich are siillle- lillli's schistose ami K''»|i'i>I<''< the less alte'.ed nl" these carry iiidi.s- iUll-i |tlil(if reiiiains. Sniiie if these Were siiliiiiiileil In Mr. ha'id ^\'llile, nl' (he Siirvi'y, who made the I'nllnw iny repnri : unci piiilM ii'iiiaiiis. .-'nine i i i imvm ^\'llile, nl' (he Siirvi'y, who made the „ ,. , I liiive carefully csiiliillicil (lie tliri'i' I'nik'nniits ynii ir.in.Hiiiil in i,'rii|iliitic sluf f|(i(ll (lie Viiknll Uiv IT, ill (iiiliK I'l'lnw- Myiiiupli Ci I,, 'rinie cm ln' m. il..ul,i Hull (lid rt'liliiitiH lire nrtfiMiK'. mill, wliilo iliiy iir" luii iilj.'.iiliii'ly cmu KimririiUji ' ' I7"_' (ii:iil.()(iV (If- TKI. VIKON (iol.I) nisTKKT. ALASKA. il''liriiiitmliU'. lliiTi' is riHiiii fur liiit litlli- cl.mlit lliat tiny loprixiit pl.-iiit Iniif- iii'iitx. Tlii'v •"•iiii to !"■ niiiiiiiit « n'filalili' t" l'-ilo|iliyiiih, nr inpssibly wiiiH' -li'iidiT ft'rii riirliiHi".. If till' fiirimr. iImv iiiiitlil aiivwiii 11' frum llu- liHWiT l)rvi hiiiii to till' Ldwit I 'ailioiiifrrimH i iiii'lii-ivi- > Knuii their (iiu'atii/.atimi \vc may coiiil It'll' that tlii'y ari'|iriilialily ii"t nliliT than tin- Di'Vuiiiaii. Such fni'-'iiii'iitsiirt". Ill k'i'iM'ral, III"!'!' I'liiiiiiiiiii ill the Miililh' iiiul I'lijH'r |)i'voiiian: ami I iiiori' tliiiii half i'.\|i<-rt that the ili-^'uvcry nf aiMitimial ami iiiiiri' (*>iiii|ilrtc inati'rial will imli- cati' all iiui' ill that ri'tfinii "f thf ({•'"li't.'ical luliiiiiii. Tiiiiiiiii'h ri'liiiiiri' ■•h'liil'l mil. Iiowi'mt, !"■ iilac'il "ii tl hsi-uri fraKiiiriits in haml. Mim ii tln'y ai-i' hanlly u'l'mTirnlly i'lriititialiU'. still 1i">n Hpi'iillcally sn: ami whili' I inlrrpn't Iroiii iIu'Iii a lii<-aiiiiiL; a> .iIi'iM' .-tali'il, it i^ <|iiili' pi'Msilili' that Kl'. '.I Kiii'iiillhif ill ii|ihaliili" liiii.-t"! f TiilikiilMlit -.-n. -, I.. •\V4'i' Itiiinpiirts aiMitiuiial malirial i whirli is in.i-t In lie dcsiicil i will lltiratliill of iipllinli. .\iiy 11. ri'ssifnti' a I'niisidfralili' pri»inii III' opiiiinii as til till- a-cnf lln' fniKiiinits li'fiiii' nil' is liazanliiiis. thiiin,'h tiny su-^r.^t Miihll.' ..r Tjipir D.'vnniaii I I iiil.r llii' iiiii'i'iiM'ii|ii' ilii' liincsliiiH' ii|i|M'.iis III Ih' \ry\ liiu' ;:r,iiin'ii aiiil.'i)ni|.ai;ili\.|y|iuivjiki'lli.',i,'iii\lilliui;i;i|,|ii,'liiiii'sl.iii('.si|(-sri'ilir.l •low llii' Cliailii' I{i\( r Id riiic-yiaiiii'il i|iiair/il('.s .ii- iiii\ai'iil K' i|iiarl/. M'anis mii' sci'ti tiiii'i'dscuiiicjiliy III'; ill iiiiiiu:li III till' spi'i-iiiii'ii llii-y nt'ii'ii Iia\i' lilt' a|i|ii'aiaii I'iiimhI um j'U. \ X X I! anil X X Xl\', llii'ii' iiiiti-i'iipN Ciir m'MmhI lllill•^ lilin'-;.'i-a,\ rixs- laliiiii' iiiiK'stiiiH' iiiiili'i-iaiii liv Itlai'k slati'. In i!ii> liiiii'>tiiiif ai'<- lliiii M-anis III' w liiii' iiiaililr. ami llii'mrk Immii Ii\ >iiiall >Ii'iiim'i' veins III' I'alcili' anil nrrasimially nf i|iiarl/. 'I'lii'ir i>. mhih' Jnini ini,'. IVi-- t|Uriil sliitpin^r, ami sli;:lil shraiint,', <'s|MTiall\ alnn;; lii'ililiin; |ilam'«.: lint thi-rc is im iiiiiriinn snnIi'Im in Ihc Jniritin;;, nur yi'iicial M'lii>lii>li \ , niir any olinT oilier r\ iileiiri' nf ri-;;iiiiial strain^. At llie rasirrn m- n|i|ii'l' cliil are the same Jime^tKnes with the same strike, lint iliiipinj; :!ii \\V. lietVM'ell t liese t«ii espiisnres eiiiiie in the slates. These ineks. 1 hiTe- fiire. I'liiin a syneiiiie whieh ivpnses liy eriisiiiii the nmlerlyiiii.' slates lietween the twii liejts iif liiiiestnne. <|'1!I!KI.AII M iM I'.M I. A I I ' 1! K. Th isalreaih ileserilieil heliiw .M\ III ink (reek anil I lliise I PI I ween (iiele City ami Charlie Uixer lesemlile niie .imil her elusely in lillni- loirieal eharaeters ami appniximaiely in I he a mini n I nl' iiietaiMnrphisiii wliieh they liave iiiiiier;fi)iie. lielnw Myiumk Creek the iiieks are sipiiiew hat inure allereil than aliuve Cirile City. Inn this may lie aeeiiiinteil I'ur liy the prultaliility that the Uampart Mniiniaiiis. in whieh the I'nrmer expusiires ueelir, lia\e been snlijeeted tii niiii'M (lislnrlianee than the le^imis lyin^'- tu the mirth ami In llie smith. It is III this ilist iirliaiiee that the existen r the iiiiinntains is pruhiilil.N line. 'I'lie i;ray liniest lilies ami sliaie III" Mymiuk ( reek, imireii\ er, appear tu uxerlie ilireetly the lueks III' the Kamjiai't series, illile aliiiM' Cirele <'ilv rucks whieli lesellllile I he: lit liuluL'iealU ar«> alsii siieeeeileil liy ilie riieks ut' the Uampart series in prulialpjy th« .same relat imi. 'I'liese nueks, emisistinu: ul' y:ra.\ limestunes ami shales, mileriip lieluw Charlie IJixcrmi the \'nkun, ami appear tu lie siiceeeileil farther np the ri\iM' liy white erystalline limestmies with interln'ilileil shales ami euiiMlumerates, ami these llniesimies earry ( arliuiiiferuns fossils ., mI. in the lueality lieluw .Myniiuk Creek t he shales assueia ted with t II ■^y:t\ litliiij^raphie liniestmie earr.\ plant remains wlileh sii^- ^est I) \uniar a;;e. In the rueks imteil near the Melu/ikak.it no fos- sils wei" luiii I, lull the j,'<'iieral litholoirieal eharaeters uf these roeks imi tl ttiit tu which tliev liaxe lieeii iiillilenecil li\ lUnainii (•iian;res st run^ily sii|j:^fest this ;feiiei'al l)e\iinian-( arliunifermis series. .Ml these rucks may then he classed toi,'ether as a siiifile series w ilh siiiiicwhat inderniite limits, uml may he emiv cnieiit ly failed the Tahkandit sories, from the 'rahkaiMlil l{i\«»r, which i nters llie Vnkim ) - mM IMAGE EVALUATION TEST TARGET (MT-3) y // A RfV ^Sis u, % I.U U£ ^^ ■ I.I 2.5 Li 1^ 6" 11 1.8 II-25 IIIIII.4 IIIIII.6 V] <^ /i ■<^y Photographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14S>0 (716)872-4503 174 GKOI.OfiV ni- TIIH YUKON (i'HJ) DISTHK T, ALASKA. iiciir till,' |)l;ici' wiicrr CMrbniiiriToiis lossils were rmiiid. 'I'liis serios may tliiMi lie (Idiiicd as coiisisliiii;- of liiiu'sloiK'S, SDini'tiiiies wliite, goiiorally j;i('cii or bhifk, sDiiictiiin'.s cryslalliiiL', often aplianitio or lilliofiiapliie. Tlio.solimi'stoiii's become tliin-boililod and carboiiaeeons and alltTiialc with slialcs. 'I'lic white ciyslallino limestones of the C'ail)i>Miferous above Circle Ci'.y also alleiiiale with beds of eonjrloni- erate confaininj? chert. Tile 'I'aiikaiidit rocks overlie the Kamiiart series directly, and the chert in the eon.ij;loiiierate mentioned above snjis^ests derivation fror\ the roeks of I he Kaiiiparl series, 'riuis an niieonformity, or at, least nn erosion interval, in .some part of tiie 'i'ahkandit sciies may be sn.spec1ei)iii!;'. OTIIKU AKKAS MAPPEn AS TAIIKANniT KOrKS. ."Mr. 11. (i. .McConnell ' notes that, on tiie J'orciipine, below the niontli of tlie Sneeor l{iver, tliere outcrop for J.") miles yellowi.sii-weatheiing limestones wiiicii yield . liri/jni rrliviihivis wilii fray:mentary speeimens of corals, and wlii<'ii iie refers, in part at least, to the Devonian. Farther down tlie river, close to tiie edjje of the Yukon Fiats (wliicli e.xtend u[> the Porciii>ine for a ioiijj: distance), these limestones aro iuterliedded with dark shales, which .Mr. 31cConneil considers as l)robai)ly Cretaceous. 3Ir. W. ()f;ilvie^ lias made atraver.se from tiie Yukon up tiicTatondu Kiver aero.ss to tiie headwaters of tiie I'orcuiiine, and so down to tlie conllueiice of the I'orcniiine wilii the ilell Itiver. On liiis trip lio has noted liiat dark siiales, overlain liy liiie-j;;raiiied contriomerates, occur aloiifT tiie Tatondii for 27 miles from its inontli. At two i)oints in tills liistauce limestones rise to tiie surface from boueatli liie sliales. ami in tiie upper part, of tlie valley of tiie Tatondii liie siiales and oon- glomerates are replaced by tiiese grayish I'aleozoic limestones. Simi- lar limestones were also met witli all across tlie watorslied sejiarating tlie Tatondu from tlie Porcnipine, wiiere they form a range of liigh mountains, and down tlie l'orcu])ine as far as tlie Cathedral roeivS. .Mr. I. C. Uussell" notes that the crest of the mountains, a few miles 'Ann. Ropt. Gool. Nut. Hist. Survey Omadii. Vul. IV, Sue. U, ii. l:i;i. «()p. I'it.. 11. i:i». » Bull, (ii'.il. Sin'. .VmiTicii. Viil. I, p. I.li). THE MISSION CRKEK SEHIES. 175 iioi'tli of the Yukon, at the intonialional boumlarv, 'Ms fompciMMl nf coinpael earthy liiiu'Stone in nearly vertical strata, strikiiit;' lU'arly east and west, couformably with tlie trciul of tiio niountaius."" THE MISSION CREEK SERIES. PRELIMINARY STATEMENT. Stratigraphically above the rocks of the Talikandit series eonio blacli calcareousor i'eldspathie .sliales, wiiicli allevnale witii tliin biMJs of impure limestone and witii beds of gray sandsbine. 'i'iicse locUs aro generally considerably and sometimes intensely folded, and j re sometimes slightly sheared and altereil, but ordinarily are fresli and recent in appearance. They sometimes overlap tlu; i-oeks of llie Tali- kandit serie.s, so that iu at least two localities visited tlicy lie upon the llanipart series. In both the.se cases the lowest bed of the younger formation is a conglomerate containing many fragnifnls of the rock on which it rests. This series has been named from .Mission Creek, iu the vicinity of which it is well exposed. It is probably, iu part at least, of Cretaceous age. DISTRIBUTION AND tiENERAL DESCRIPTION. NM'OLKOX VXD CUICKEN tHEKKS. According to the ob.servations of Mr. Schrader, the mouth of Xapo- leon Creek seems to be nearly on the contact of the iiampart series with the Fortymile series. Just above the mouth, however, there is encountered, resting upon these older roeksj a conglomerate, which is made up at the bottom of jiebbles ranging iu size from mere grains to a foot iu diameter. These pebbles are subaugular in shape, showing that they have not traveled far, and among them are fragments of quarlzite and of vein quartz, probably derived from the IJiich Creek or Fortymile series; of aplite and porphyry, similai' to the dikes already mentioned in these older nicks, and of comi)act gray and green slate, identical with the rocks of the Hamjiart series exposed on t.ie ridge between Fortymile Ci'eek an K. and dii>i>iiij; ■M)" X\V. Tlic y()iiiij;ri\ed from the biotitc in the ])roccss of its decomposition. The microscope al.so shows tlie shales to be com- posed of tiny particles of ([iiartz and snbmicroseopic ag^'re.uatcs of decomposition products, with much carbonaceons material in the l)lat'k varieties. IIKI.IW |-ol(TVM!l,i: IKKKK. On Forty mi 1(> ('reek,alioiil .'i miles above itsnionlh, th(> schists of the Korlyniile scries are siK'ceeded by black shales and sandsloiies, strik- ing: east and west and dipjiin^ 111 N. Tlwse rocks are t ra\i'rscd by shear zones, aloiiji which there has been some mctaniorphism, partly dynamic, but iiriiicipally aiincous, evidently resullin^.' from w,".;er,s which have coursed aloiiij these zones. As the result of tl. is action the rock in the iiiMjihltorl 1 of the shear zones is often somewhat iniprcfjnated wi.h sulphides, and fre(|iiently small ly (Im- 1o iron and tin' jri'ccti to cliroiiiiiiiii. 'I'ln' altered rock is said to sliow the presence of precious iiii'tals im assM\- iiifj, but an assay made In the lalmralory of the Sui\cy sIkiu-. mo appreciable amount ol' eillier ^old or sil\er. This rock series is exposed \'vii:u llie|>oinl al::)Vi' uienl ioui'd toliic month of Forlyniile Creek, and from here miles. I''or the wliolc distance tlic lock consisls of IdacU sliaies alternating' with thin-liedded ,u;ray sandstones and iimestoues. The beds arc held into broad, open folds, which u:ro\v more pronoiuieed as one {^oes down tin' ^'ld^oll from the mouth of l'"()rtymili' (feck ami approaches ncai'ei' the Mammolh Mouniaius. There is also sliulit faidtiliu'. \'\i!:. HI, .1, showsthe structure of a hiu'li and loiii;' sect ion of Fiu. til Sl^(■l.■lu•^< (if ilistiii'l.i.il stnitu of Mission n k soi'i,.s. those bedsexposed in a vertical olill' on the river aboiii lo nnles ludow Fortymile Post. These rotdis are cut by occasionid dikes, whicli are irenerally li}fht- yollow in color. Speciuu'ns of a dike ro<'k collecte(i at the nionlli of Coal t'reck have been Ibnnd to bo porphyry. MifVdncopic chiiriirhrs. — The Ihin-beddeil limestones founil near tlio mouth of !''ortymile Crook, and below thai cri'(d< alonnthe N'ukoii, are ordinarily dark-n'ray in color, and nndci' the micros<'op(> are seen to bo made ui) of very small calcite j;ranules with no evident reu'eiu'r- atiouororystallizatiou. Alonj; the sheared ami altoi'cd zones a short distance above the month (d' the crock, however, the limestone has boon [)artly rocrystalli/.od and dolomizol, and the nucroscope shows the development (d' occasional inetanior[)hio miiu'rals. There are also 18 QEOL, PT ;J 1- m J . -!*' 178 GKOI-tXiV OF THK YUKON GOLD DISTRICT, ALASKA. small niiisscsiif a dark-hnnvii iiiclallic mineral, wliicii arc surrouiuled by 11 .slif,'ht stain of j^rccii. I'liciiiical tests made liy Df. Ilillehraiid, ol' tiieSuT'vey, sliow tiiat the (laik-l)i(iwii iiiinei'al is probably chroinito, ami that the ^fcen .stain which sui't'oiiiids llu'se grains, aud which gives a .i;eii"fal eoloi- to tli(> foek in the li<'l of fclty actiiiolite. 'i'his st)ecimcn is traversed by many parallel fi'acturcs at riglit angles to the i)lancs of siiearing, and both along these fractures and along the shearing i)laiies a great deal of iron o.xide has beeu deposited, whicli gives the Itrowii coloi' to llio rock in Ihc field. MISSION I i;i;i:k and iii-.i.ow. About •2i> miles below the mouth of Fortyniile Creek the series jii.st descril)cd gives way to the J{ampai'l series, but 5 or 10 miles above Mission Creek the liaiTqiaii .series is again overlain by thin- bedded black Ol' gray limestones and limy shales whicli seem t(j bo lithologically like tho.sc exposed l)elow Fortyniile Creek. The plica- tion of the bods here, however, is much more intense, the strata being com i)rossed into close folds which are often overthrown. The sketch in lig. 10, Jl, is from an exposure of these beds on the Yukon above Mission Creek. It is to be noted that the locality is in the foot- hills of the sierras which have been called the Mammoth Mountains. The ineroa.se in the inlcnsily in the folding as one apjiroachcs these mountains is very mai ked. Although 1he.se rocks are closely folded, there are no .schists or l('on (rccU. ( liickcn (.'rt'ck, tlic iiioiitli of l''.irt yiiiilc (reck iiiul hi'lnw. Mission ( iccU iiml vicinity, and iiciir llic Kamlili Uivcr. arc ail nf nx-lvs liaviii;: similar litluilDjflcal cliaracters, hciiig composed ol' dark calcareous ami cinlion- accous slialcs with tliiii-boddc(l impure limestones ami sanmeratcs. Tlie^e rocks cairx iiii])urc coal seams and i)lan1 remains, wliicli, so I'ar as found, were not idcntiliable. In all the ( Iliis iialm-e isofton found iiitho upper coii- tili.iiieralie series, and is not. sofarasohserved. found in thelowor sluilo a)id earlMinaeeiPiis limestone series. ( »n a small creek a few miles lielow Coal Creek, a short distai'ee up. the same coal is found. It is i)rob- nlile, tiierefore. liial at this point the upper confil cratie ( Koeene) beds conu' in, overlyin;; the rocks expo.sed at the mouth of Fortymilo Creek: and this seems to furnish strati,i;raphicai evidence for tlie cor- relation of these latter nx'ks with those at the mouth of .Mission Ci'cek. The fornuil ions exposed alon.ir the \'ukon. in the vicinity of Fortymile Crt'ck. .Mission Creek, and Kandik Ifiver, therefore, seem to form a continuous belt infoldecl with the overlying: conjilomerato series anek, are characterized by ,. la.sal con!j;lomerate whicii rests uneou- fornuibly upon the l{ampart and Foi'lymile series. All tlu'se rocks nuiy thou be prcvisionally ci)ri'elated as ii sintflo series, which may b.' called the .Mission Creek series. The upper limit of this series may be repirded as the heavy beds of conjj;loinerate, .sandstone, yrit, and shale, which carry abundant ])lant remains and beils of pure li.i;nili(! coal, with brilliant luster and conchoidal fracture and freiiuent grains of amber. The lower limit of the .series is not so clear, but is approxi- mately the heavier and purer limestones, with some eou}i;lonierales and shales. In some of tlies(> limestones Carboniferous fossils are found. The lithological antl structural resemblance between some rocks which have been classified as j)ai't of the Tahkaudit .series and some wliicli have been put into the .Mission Creek series is v(!ry strong?. For example, the I'oeks lu'ar the nH)utli of Fortymile Creek strongly resemble lithologically and sti'ucturally the rocks below Mynook Creek, which carry plant remains suggesting Devonian age. Possibly further evidence may show that some of llie.se rocks should be ])ut into divisions different fi'om those whi(di are now considered best; the jjoint aimed at is simply to make a provisional classidcution. AOK OK THE .^IISSIOX CKKKK SERIES. In the Alission Creek series no fossils were fouml by the United States (Geological Survey party except indelerminable plant remains. Mr. K. G. .McConnell,' of the Canadian Geological Survey, disi'overcd below the mouth of the Tatonduc liiver, in the shales uiulerlying the heavy conglomerates, specimens of Aucella mosquensis var. voncen- ' Auii. Rept. Oeol. Nat. Hist. Survey C'niiailn. IsnHjtli, V l)ut not enorinous tliiekness. 'I'his series often rests tineonformahly upon the Kanipart scries and older rocks. It is norniiilly underlain by the Tahkandit. series, the odfies of which it overlaps and from which it is iiroliahly S(>pai'ated by a sli;,dit dciirrce of uiiconfoi iiiity. .McConnell ' notes on the I'orcupine Hiver, below the mouth of Driftwood Kiver, the expo- sur(> of a contjict between sandstones and (luart/.itcs with underlyiiii,' coni])aet bluish limestone. The sandstone iiiid quai'tzites jire overlain by soft bluish shales with harder ealcareoi;s layers, and are sii|)- posed byA[r. ."Mcl'oniicll to be Cretaceous. The(>oiMpact bluish lime- stones are lillcd in i)laccs with broken criiioid stems ami other fossils, and iiro referred to the I'aleozoie. The contact between the lime- stone and the overlyinjj; rocks hits the appts'iraiice id" beini; sli^rlitly discordant. The .Mission Crook series is directly overlain by conj^lonieraii<- beds Ciirryinji; abundant i)lant remains which indicate Kocene aj;e. The siKblen abumlance of these coimlomeratcs ^ivcs some reason I'or susix'ctiiifi; a slij;ht unconformity, but it certainly is not ureal. Tl 10 oeciirroiice o f th icniis Alice ill the .Missi(jn Crt scries shows that it is, in part at least, low(>r Crolaoooiis, although otl re (doselv related to ti periods maybe re])resciited. 'I'he series is more closely related to tlio Tabkaiidit series than to any other, ami the litholouncal and paleonto- loflical boundaries between the two arc not well determined. They may be colleotiyely considered, however, as a grand series of setli- ments raiij;iii}j: i.ii a^e i)rol)ably from Devonian to Cretaceous, and of this the Tahkan Op. cit., p. ia«D. 'Op. oit.. 11. li-.D, i-':d. \H\ (;i;<)I,()liV OF TlIK YUKON (iol.n DIsTRKP. ALASKA. l.c-imiinvnlllM' Fliils, n.cks liiivin- lli.->.'si lii liol.i-ical iVjiliiros .M.^iir, l.iil Irnm tliciii ii,. I'os.sils wm IliTinl. 'Ilicy (.Vfplit' licro li-uciiilii'i'lii^' liiiioidiics wliicli i-.ii'i'v .I//-///'" ri I iriiliiri.s nnd Vcllcpw l> I'liliriMClllMI \ >|)r('ilM('tlN 111' .Mll'ltls, alH 1 Wl iii'li an- iis iilcrcil hv "Slv, .■M.'Coiin.'ll as ivlVrahl.', in part al Ica-l. i" Hi" I ).>\(>riiaii. Tlit'so ivnlvinj: nicksarc rcpr. x-iili'ii on the map of llif \iilvnii iX'M dislrict as l)('l()iiu;in}j: In tin- y\ issimi ('i'(c u liilc llir iiii(lcrl\iiii;' liiiu'- sliiiics all' inappi'il as pai' I'ldspcrlnl'S wllii I (if llii' 'ralilNainiil scrir III llic lii; ri'iici' (if cdal (111 t 111' .Missidii ( 'ri'c lia\i' passc(l upllic Kaiidik lii\« r.ainl tliciicfacniss r.lack liivcr and diiwii idllit' i'lii'cnpiiic, icpoi'l tlicociMir- llic l!i;r I'.kudv Uivcr. U is pn.lialdc, tlicrcforc, iliat rics (ir ihc ovcriyiiiir Ki'iiai sci-ics. or liolli, aro • \|)oscd. 'riic l(icalii.\ (if llii'st (•iii-rciiccs. houcxcr, can not llii'i'i be asci'ilaiiifd from llii' |irospccloi> l)i< irmalions as diMwii aloii ilid llicrcforc llic Imiliidarii'S of i; till- lily r.lack Ki\ cr on I lie map aro liy])oili('' 'al. .Mr. \V. Oyilvic' slates that aloin; tlic Tatondii liivcr for J7 iiiile.s iiliovo its monlli all" dark shales ovi'ilain liy rnu'-jiraiiifil coii^rlonicr- atcs, llicsf beds hciiifi similar to lliiisc ohscrxcd on llic Yukon. At t wo piiinls this distance limestones rise to the siirfaci from lieiieatli 1 lie shales. In the upper jiart of the \alle.\ the Mocene. In the followinii' payes are described certain rocks which ajipear to belonj; to this series. 'I'liese are all in localities examined by the I'liited States (Jcolouical Siirvt'y parly aloin; the Yukon ]{iver in the suinmci' of bs'.iil, i.\m Hc|jt.(ii.'iil Xiit Ili»t.Sii)'V('> (■iiiiu(la.l.'i-v'< si'. V.il.IV.ii. risD, •Bull. U.S. Uuul. survey Xo.fl. t'orri'limuu Papirs. Xl'oi'ciu'. |).;.':U. TIIK ::KN.\I Sl'.UIKS. IS;-) DlSTHIIifTloN \NI> (iKNKIiAl. |iK,S( l;l I'lK iS. Jtihiir .]/l:^.siiiii Criil;. — Ahniil 7 iir > iiiilc^ ln-lov .MJN.siun (ircU. mi the \'uUiPii, llic tliiii ii'ildcd liiiii'sldiics. siiiiilslniifs, ami citilMiiin \is •shak's (if Ilic .Missidii (I'l'ck sci'ics aif Miccci'ilcd hy ii\cil\ iiii; iiias>i\i' eoiiKloiiicratcs. Tlic |i('hl)lcs in ilicsc ciiimliiiiiciali"- aic Miiall, anil arc iiioslly luadc iq) of (litlVrciil xaiictics of t[\\,\' .mil dicri or ,jas])('ri)innd;ini le.il' iinpies- sions, and ahoiii J,") miles below 'lissir)n ( fi^'k a colleei ion of these fossils was made, from which the lollowinji' species were irvt'd Iilant i-ciiiains. I.illioiofjically iliosc beds an' exactly like those in the locality just described below .Mission (reek. As in the last-named locality-, the jiebbles in the conij:lomcrate consist mostly of silica in its various I'oiMns, but a siu'cimcnof ilai'k ;ri'cenisli-;;iay ,^rit is seen under the miei'oscope to be 7nade ui) of irre,i,'ulai- and often sharply anij;uhir fra^Miientsdf feldspar and iiuartz Tlie fi'ldsi)ar, which is plajfioclase, is the pi'edominalini: material, ami occurs in bi'oken, lath-shajjed erys- stals. The Lfraiiis of quart/, are not much ronmlcd, and there is some orthoelase, aniiile. lioi'ublende, anil mica, with line calcareous and kaolinic material. The naluic of this ffvii shows that it has been derived from some basic ii;:iieous I'ock, probably a diabase or diorite, and the diabases of the Uampart sei'i(>s may be susju'cted of haviuij fui'nislie(l the material. The richness of the rock in hiirhly |ierishable minerals, moreover, and the anjrularity of the irrains show that the material has not traveled very far from its oriirinal source. On the river al)o^'(> ami below th(> locality just mentioned come the undcrlyini;' darker, ihin-bcdded limestones and shales of the .Mission Creek series. Cmil Cfdk. — On tloal Ci'cek. which enters tlie Yukon a few miles belo 1 ihe nKMilh of Fortymile (reek ans above the mouth, as .Mr. ( ><;il\ ie. of the Canadian (ieoloi^ical Sur\ey. has informecl the writer. One specimen given by Mr. Oi::ilvie was a pure, hard, black liirniti lal with bril- liant luster ami perfect eoncholdal fracture, ancl contained t iny tleeks of ])yrite and larjrer' uraius of amber or amber-like icsiii. This coal is like that found so frecplently in the rocks of the Kenai series, and it is probable, Iherefore, that these rocks cross Coal Creek some miles above its mouth. On a small cie<>k a few miles below Coal Creek, on the sanu' side of the Yukon, coal is also t'ound, identical in appearance with that on C()al Creek. The e.xisteiiee of line-;rraiiu'd conglomerates overlyinj; dark shales nloufjthe Taton liiiicstonc is in tliin layers, gray or jjfreoiiish in color, very fmo-Kraiin'd, and wiih a sniooili mn- C'hoidal fraetiUH". In tlic slialo arc froiiucnt scams of I'alhcr impuro lignitic coal; llircc distinct scams arc c\p scries has a strike due north anil a ilip 45" W., and ali month of Myuook Creek are ex|)osed conglomeralcs, gri.s, and shales similar to those just ilescribed. The beds arc f.iirly well con.solidaled, aitliouiih some layers are lnose and iucoliei-ent. The coiiglonu'rates are generally line-gi-aiuc very great, unless there e.xist faults which were not noted, and which may jiossi'bly operate to increase! the apparent thickness. The uppermost beds exposed have a char- acter and a composition substantially like those of tlic lowest bcils, ^1 18H (JEOLcMiY OF THK VIKON GOLD DISI'KICT, ALASKA. l)Ul I M'i'c IS a III iirkcil ililTtTcii lli(' dciri'i'*' <>r CDiiso iidati coiiciciicy. tain sdiiictiiiH's Idosc la\ C'liiiiildiiicrali's, irrils. JHmI "lie lowest beds near the iii(iulli(ir .Myiiook ('rci'k coii- is, yd arc ordinarily (irmly consolidated ^liali's. Ill llic liiirlicr liori/.ons, liowever. Ins consolidation liccoiiics \ei'\' yrai iiaily less, until the ni)i)enni)st bcilsareol' little coliereiil clays and shales with loose sand and uivivels. ^Mlhonjfh these ui'a\('ls eori'espond in c(nn|iosit ion to tin niilonicr- ates in the lower beds, they are so little iiidnrateil Ihat the pebbles can be easily and cleanly pickc mat rix ami the whole rock can be remo\ed with a slio\cl. The jfei'eial ■> l)e(ls. therel'ore. is decidedly dilVerelit from that of the lower ones, and if ihe two localil ics were not connected by a <'on1innouse.\i)osnre, the sanei' 'h .al seams arc u-ciierally oxcrlaiii and underlain by sandy cla\'. and arc associ;iled wilh earlionaceons shales forc I he whole series < arsto beloii"- to 1 1 le r.ocene Slil the loose, iiicoliereiit nature of the ii|i|icr strata, comparecl with the coiiiiiact. well-consolidated condil ion of t he Kocciie in other localil ics, g'ives rise to the doubt as to wlicl her all should 1 lassilied under exactly the same head, and whellu'i'the iincoiisolidated bods may not beloiii;- to a somewhat more recent ])eriod. I /"in ///( 'I'll III 1 1 .V boll I :;.") miles abos'c the mouth of the Ta nana. on the \'ukon.coiiie in coarse <'oni;lonieratcs, yreen jirils, and mica- ceous shales only part ly consolidated. The Liriis and the liner mate- rial of the coiiiilomerales are e\ ideiit ly made up chielly of detritus from thediabasic rocks of the Kamparl series, while the pidibles in the coimioinerate are laryidy of the \arieolorcd chert or Jasperoid, which occurs so abundant h in the same ro<'k Thei e are also occn- inal pebbles of white eryslalliiie quartz which may be derived fi the X'eins of the Kirch Ci k or l''or(yinile series: and in coarse urits there is much line uranit ic del rit us. Tlii some of tin s conulonierate overlies the Kamparl rocks, which arc exposed fart her up the river, and for some distance below the contact has a li-eiieral soiithwesl dip, which it chan.u'cs farllu'r down for a northeast one. The strike is usually noriM or northwest, so Ihat the whole belt seems to have a jicneral .synclinal structure. I''art her down the river llieso eoiiKhun- eiates arc succeeded by ohler rocks, consist inn' in part of niica<'eous and calcareous i|iiart/.ile-scliist wiih inlcrsi ratilic oi' Ci iindies in diameter, and are commoidy siibaniridai' in shape. One liowlder of (piai'tz noted was over a foot in diameter. (Jreeii dialiase and otlier cliai'aeteristie foeks of the Hamjiai't sei'ies make np a lai'y;(^ propoftion of tile ])ebbles and bo\> Iders. 'i'he micai'eousipiarl /.-schists of tlie ISii'ch ('i'e(d< or l'"ortymile series also make uj) a \ery lar^te part, and tliere are qnai'tz and chi'rl or jasjieroid of all \arieties and of all colors, (iranite pebbles, however, conid not lie found in this localitv. I'l. XXXIII is a i)holoj;raph of a mass of this con,L;larl series, of mica( lis schist fiom the liii'ch ('re(di or I'"ortyniile series, and of coarse fii'anile like thai of the great intrusive ma.sses obserx'eil in the Lower Kamparlsof the Yukon; there are also frajinicnls of line-irraine SW., and the fold- ing al this latter jjoiiit is more marked. In both these localities the conglomerates are X'ery coarse, the pebbles being as much as il or H inclies in diainetei', especially tho.se of granite. About 7 miles below the last-named locality were found sainlstones and soft iday-sliales, both being i)lant remains. The sandstones aregreeiush in bands, like those above described, but ,, mostly gray and of pure nposilion, jcing made up eh lolly of ((iiart/, grains, while the mdi nary green sainl- stone is largely composed of feldspar. These rocks strike \. ijo K. and dip 35° XW., and are continuously exposed, with a uniform di]), for 5 or (I miles along the river, thus albu'dilig a line cross-section. The thickness of strata exposed in this section is apparently very great, but it is probable that this appeariince is largely due to fault- ing, as noteilby I'rof. I. ('. Unssell.' Of this Professor Russell speaks as follows: The finest eXHiuiile of nionoclinnl structure seen in nacpmliiis,' the Yukon. thou},'U on ii coniparatively small hi'ale. was in cliffs of sauilstono anil slate l«)Vilfring the right hank of the river tor sevrnil niilcs, at a lofahty some I.") or L'll luilcs lielow 'Note8ontllesurtlu■l^^,"M■l(.^;.v.>l ,\liiskii: M-.U. Uim>1, Sue. AiiuTii-a. Vul. I. p. liw :5, ,t >- ,1 190 GKOr.OGY OI- THE YUKON GOLD DISTUICT, ALASKA. the moutli of the Mi'lozikaknt, or iniilwiiy bptweon Xnlato and Nnwikakat. Thfsc Bamlstoncs contain the leaves of diriduonn trees, and belong to tlie same systiin as tlic roiks at \iilato. which have been described by Dall.' The river bank at the loiality referred to is extremely preciiiitous, and exiioses a fine section of tlio rocks, wliich dip. in general, northwest 2.")° to W)', excejit where disturbed l)y fanlts. Tlie disi)iiiceinents trend near'.y north and south, and appear in the clitTs as in a diagram. In the best-exposed portion of the section there are six or eight important fa\ilts within a sjjaceof about S mih's. These are parallel, and liead to the east at an angle ranging from )i'i to4()\ In each instance the strata are distnrliecl on ;i|)proaching the breaks, but soon return to tlieir nor- mal dip. At each fa\ilt a lateral valley has been excavated, the westsiile of which is a smooth, even rock sIojh', frequently slickensided, and is in reality the heaved side of the fault. The east wall of each of the valleys is rugged and broken, and the strata in the iirojecting ledges usually show a high dip .oward the east. In other ravines, where the structure was not clearly visible, the peculiar topograjjhic conditions imlicated a similar origin. These faults are iiLstrnctive Un- the reason that they illustrate the manner in which a series of displaced blocks sometimes jiresent a nearly uniform same s>'<^"'"- isli siiiidsloiies aii i)laMt remains, were found fre.sh-watcr shells, which, however, are not eliar- aeteristie iMioujrii to determine the horizon. At this point the be Is strike \. 7(i" K. ami dip 40' \W. ^\t a point some H or 7 miles beyond that last mentioned weree.xandncMl bliiisii-jiray and brown sandstones, jrrits, and eonj^h)inorates, difyeriii}? considerably in appearance and color from tlio rocks in tlio localities further U]) the river. These beds are considerably foldcfl, and even slifjhtly overturnes. The conglomerate contains jx'bblcs of schist like that of the IJircli t'reek series; of diabases, tiilTs, and chert from the Rampart series, and also of : haly green liniestoin' in large pebbles, the derivation of which is uncertain. The general .strike here is X. 0()° K., while the dip varies from :!0" N\V. to vertical, or is csveri locally reversed. About or 7 miles fiirther down come bluish-gray sandstones and sandy shales, striking N. 7o° E. and dip])ing r)0° SFL Tliese (iontain many plant remaiiis similar to those collected in the other exposures between here and the month of the Melozikakat, and the sandstones are rii)ple-nuirked. A few nules below this last exposure come in high bhiffs of horizon- tally bedded silt which conceals the other formations. Tliis silt is >Aiii. .Toiir. Sci., L'd serii's. . il. XI^V, l.-sfts, pp. 117-118. iii !i if-^ i :i ii rf4 , .1 i m BPDBR.] THK KENAI SEIilES. 191 the only deposit exposed alonj? 1 lu; ])anks for about ;t5 miles, ami it apparently extemls away fr>iii tlie I'ivei' mi liolii sides for a iimulier of miles, for the country is eonip(jsed of broad, level Hats, wiiieli foim a marked contrast to the rougher topojtraplix' alrnxf and below, and which stretch away to the distant hills. It seems pi'obable tliat tliis silt was deposited in the bottom of a lake wliieii ()<'eu])ie(l the rejiion of the flats and whieh was drained in cinnpai'atively recent time. At the end of the Hals are two eminences, whicii are called the 'I'win Jlountains; they are close toy;ether, on tlie left-hand side of the river. Nearly opposite these mountains, on thi^ riijht-hand side of the river, is a steep rock clifT, about :!(Mi feet hijrli, comiiosed uf c(imi)aet, blue- gray slialy limestones and sandstones. These rocks reseMd)le, litho- logically, those seen farther up the I'iver, and contain indistinct plant renuiins, buti they also contain marine fossils, which Dr. Dall considers to be probably of Jliocems afj;e. .\n estimated thickness of al)out Beport of an Expedition to the Copper, Tannna, and Koyukuk rivew, Senate Doc., ISO", p. ISO, 1 "' m ;*. I 11)2 (IKOI.OfiY OF TIIH YUKON COM) DISTIUct, ALASKA. jiinl some irnlil was tiikcii "ill. A posl was cslaMislHMl ini this rhci'at Aiclic Cil \ , iioi'l liwcsl llMl mill's or so Iroiii 'I'aiiaiia station, on tlio ^'ukoii. lint lias lately liccii aliMiKliiiicil. A< I'lllrifj to tlic ri'ixirts ol' in'ospcctoisaiiij tiadrrs t he ;.'ol(i is cDiitaiiii'd in IhmIs of cnn.irlonici'alt'. (■()l!l!i:l..\ll().\ AM) A(il:. Tlio coii'iloini'i'alif series exposeil below .Mission Creek and lliat I'oiinfl above the Kanclik ii'ivcr evidently ai'e the same, since tliey ai'O identical lit holoirically and st ijitii;r'aplMcally, contain the same phiidi lemains. and ha\t' the sam<- amonnt of imliiiation and l'oldiiik the lowei' bed.s in the section exposed havo the same character as those a! .Millei"s coal mine, but are less consol- idated. Toward the top of the thick scries e.\]iosed aloiiir the banks of the \'iikon at this point the beds bccimic proj^rcssividy less con.sol- i]mliis liulsamoides Hecr. Platami.s sp. Vitis creiiata? Hecr. Carpitcs s]).; and from the locality below .A.ission Creek — Seiinoia langsilovfii. Ficns? alasttaiiay Xcwli. C'orylns iiiac(inarrii'.- (Forbes) Hecr. Ptprosi)('riiiite.>< (Iciitatii.s Hecr. Since these three localities have at least two species in comnion. Dr. Knowlton considers them as approximately e(|uivalenl in ]ioint of ajro, and the combined collections from the three localities j>ive 7 .species which are characteristic of a liorizon formerly known as the "Arctii;" ."Miocene, but wiiicli is now considered to belonji: to the I'pper Koceiio.' The beds broufjht lofretlicr in this correlation are closely alike lith- olofrically, with the exception of the upper beds of tlie series exposed ■ Sen Di-. Kii.iwll. Ill's report, pag,. 1!« ; nlsu A review (if tlie fossil flora of Alaska with ilesei^- tiou of new species, by F. II. Knowlton: Proe. T. S Xat. Mus.. Vol. XVII. pp. ■Ji\:,-JH). ' It M ■ : ' I i TIIK KENAI SEIUKJ*. Ift3 iinuH'diiitoly aliovo .Myiiodk Creek. 'I'liesc Jire no liti Ic (■(PiiMiliiliitnl ill i'()iii|)iii'is(>ii with till' liultoni i>t' ilic suiiif series and with llie incUs o.\|Mis(',(l ill tile olliiT liicalilics, liial IlifV woiiiil luir.il\ In- (•inii'lalcii willi tliciii hytlii'ir iiliysicai cliaraclci's. Sliil, llic I'liaiiu'f t'lnni ilic lower rocks lo tiie ii)»|)er sands and gravels is seen to he \ cry u'radiiai, and llie series to lii' cont'(H'iiiat)ie from lop to liott^mi. If t his corri'la- tion l)c correct, we lia\'e al)o\c .Myiiook Creek a xcry i^reat tiiickncssof fresli-water strata Mtdozikakat the first Terliar.V rocks exposed are con- fflomerates, s^i'cen grits, and shales. Farther down the river they aro overlain by \mnH- and liner sediments, eonsislinff of jriay sandstones anil soft clay-shales. In the upper beds were collected frai;nienls of wood and indetormiiuble dicotyledonous leaves and a small fern, which, aet'ording to Dr. Knowlton, somewliat resi'iiibles I'l iiqitt'i-is (ircticd Ileor, but probabl.v represents a new species. Dr. Knowltou says in rcwird to these beds: "The aiie is uncertain, but from a nn — ber of shells in tlio sanui matrix .Air. Stanton ini'liiied to call it, a., least provisionally. Eocene." The spe 'cs containing the fossil shells referred to were submitted to Dr. W )all, who eharaeterizcd them as follows; Frosli-water gamlstono with remiiins nf vegi'tatiou. worm (?) triiclvs, ol)scuro l)ivalve imiiressions (possiljly a small Uniol.aapecics of Giiiiioliasia, Anrylus, and a ver.v elongated, rather nmooth nhell, which appears to lielong to thi^ Kenus Cam- lieloiiiH. None of these in iilentifial)le with any ilescriljeil American species as far as can lit! juilKcil ti'oiu the material. Thesandstoiies below Kaltagand above the Yukon delta are referred by Dr. Dall to the same series as tho.se already described, apparently on stratigraphieal grounds and on account of their probable conlinu- ity with the beds on Fnalaklik River and Norton Sound, which con- tain fossil leaves characteristic of the Keuai group. All the occurrences which have been described, therefore, may bo correlated with the Kenai si-rics of Dall, and mr-y be referred to the Eocene. The rocks may be summarily described as cousisling of a 18 (JKOL, rr 3 13 \m i: ■ - n:' L M WW \ 194 (JI'.OI onv OK TIIK YUKON OOT,D DISTUICT, ALASKA. j;rcal tliicUncss of soiiicwliiit Icioscly ciiiiMdlidutoil coii^'loini'nitoH, hiukI- stoiK's. iiiiil sliali's. all irriiiTally (.'iccnisli in ciilnr. 'I'licy confain (•vci\ \\ licii' (ilaiil remain^ ami t'ici|iii>iit scaiiis iif liyiiilc, and ri'sl. lin<'i)iir^e\ eral I imes as tliiek as the iiiiderlyin},' .Mission Creek series. This is a mere ^'ness, lint serves to <'()livey the imjires- NJoii formed after viewing;' numerous extensixc exjiosiu'es alon^' the hank of t he river. .1 list above ]\lynook ( reek t he seel ion of beds I'on- lainiiiK tlie same s])eeies of fossil plants is at least Ih.ikhi IVet thick if there is no faiiltin.a. iiclow the .Melo/ikakat, also, these beds occur for many miles with a general northwest di|t, passing' upward from conifhmierates to liner-u;i'ained sandstones and shales; and e\eii allow- inirfora ui'cat deal of fault ini.', the actual thicdviiess of strata e\])ose(l here must be \cry u;i'eal. REPORT ON A COLLKCTION OF FOSSIL ri.ANTS FROM THE YCKON- RIVKU. ALASKA. oHTAlNEl) RY MR. .1. E. SPi'RK AND PARTV DURlN(t THE SUMMER OF IsiMi. By F. IL Knowi.to.n. i>r,s( liii'TioN. This cdllcrtion. as sulnnittcil to inccdnsisti'dof nliont l-Ti spccinions. ami re])re- sents 111 liii-iilitii's at varicms iioiiits aluiit^tlic Yukon lioni Walkers Fork of Forty Mile Creek to tlie vieinity nf tlie iiimitli of the Koyiikuk. a (listaiice of soiiieMiii) miles. Tli(> entire collection was carefuUv arrani;i'(l l>y Mr. Schrailer by locali- ties, anil the iiositioii of each iudicateil on a map of the Yukon, together with the Jirovisioual (leleriiiiiiatioii of the Keiilo;iical hori/oii. The material is, \nifortuiiately, very imperfect, the plant remains boint; in alumst all I'ases only fra;;meiits. The ileterminations. therefore, are more or less doubtful, and can not have the value that is necessary for satisfactory identifica- tion of hoiizdiis. The report ia thori'tore to be n>.i,'arded as provisional, and sub- ,iect to revision when more ])erfect material can be ot)tained. I have given iir.st a list of the localities, witli the plants from each, relegating the discussi,)n of their age to the end of the report. 1. Foirrv .NMI.K. NAI'cl.F.tl.N CItKKK. Material a black carlxmaceous shale. I'ontain.s idnnt fragments, but so imperfect as to bo of no value. ™. MISSKIX CHKKK. Material a very black cari.onaceous shale, with minute, wholly undeter- minable plant fragments. a. IIKI.OW MISSIO.V CHEEK Seipioia langsdorfii. Ficus? alaskana? Newb. Corylns macijuarrii? (Forbesi Heer. Pterospermites dentatus Heer. & KOSSII- I'l.ANTrt. 196 4. TWKNTVtlVK MII.KH MlliVt; .MVMllllv lilKKK: Mll.l.t^lt H ( llAI. MINI". PhniKiuitcs iiliiMkaiiii? Jlccr. Kii'iis'.' lllil^l^llIw^.' Nt.'\vl>. ('(irylurt iiiiu'(iimrrii iTorlirs^ Ilrrr. I'ii|mliin liiilHiiiiiniilis lli'cr. l'l;itainis sp. VitiH cri'iiutu'.- Hi'pr. Cni'liitrs sp. W(hh1. Stems mill fr.ifimc'iita. "i MM-I MII.KS AMIiv K MV\CM1K ( IIKKK. NothiiiK '"111 111' iiiiiili' dill li'diM lliis iiialiM'i.il. It. .irsr AHnvi; uit Noimi ui' \n simu i ki.i.k. FicnHV iiliiskiiiia Xcwli. Ciirylns iiiaciinarrii (Furlicsi llccr. Wodd, apparmitly ora. but F incline to rei^ard the northern Horas as a little higher, therefore jirobably Upper Eocene in a.Lfc. They can not possibly be Cre- taceous. Locality T dielow Mynook Creek i alfords only frairments of dicotyle miles below Taiiana) are also fra};nients of dicotyledons, but none surticient for identification. There are sevon'l finely pre- served cones that appear to be the same as Ileor's Piiiiis iiiiicfliiril. The a,i,'e is Pliocene, or possibly upper Miocene Tlie only form from locality 1) (below Jlelozikakat) that I have been able to determine is a small fern somewhat i-esemblinf.; I'trajih'rin drcticd Heer, but proba- l)ly representing' a new sjiecies. The age is uncertain, l)ut from a number of shells in the same matri.x Mr. Stanton inclines to call it. at least provisionally, Eocene. THE NULATO SANDSTONES. 'i'lic Niiliito I'ocks have already been (loscrilied by Dr. Dall.- Tlicy (•(insisl of iiiariiic Mioct'iic saiulstdiics and slialo.s wliicli (ivcrlic tlie rocks of llii' Kciiai gi-oupaiid arc (>.\[)os('d aloii;;: tlic Yukon IVoni near KaltafrtoflicKoyiikiikMoiiiitaiii. 'IMicsi'l^'dsaroortenripiilc-inarkcd, and I'otitain vcjrctablc frairmt'iUs. In issi; |)i'. Dall obtaincil Cossil.s r('l)ios(Mitiny: the ij;cni'i'a Moiliola, 'IVllina, .'\lvtiliis, (iaslrocliii'iia, and .■\lya. About Jii miles above llie mouth of llio Koynknk, noai'ly oi>posito tlit'Twiu Mouiilains. isa stccpcliiroii the rijflit-hand sidcof tlio Yukon fisiiiu: 1o a lu'lifht of ;)(I0 iVcl or inoic. Here the Ix'ds arc well folded and have a {joneral strike east and west. They eonsi.st of blue- .tfray siialy liinestoiie.s and sandstones, contiiiuiiig doubtful plant trtig- nients ami ea^ls of marine shells. Speeiitiens eolleeted from this locality were submitted to Dr. \V. II. DfiU, who eharaeterizod them as follows; Marine saiid.stone, jiroliably Miocene, with poorly preserved casts of Thracia (ilycimeris, Tellina (sub^. Angelusi, Macoma. Yoldia (or a yoldiform Macoma), Xiicula, a species with heavy shell, and a partial imprint of a naticoid shell. THE TWELVEMILR AND PORCUPINE BEDS. TWELVEMILE HEDS. Twelremile Creek is one of the bran<'hes of Mission Creek. Xear the point of junetion of these two stri-ams are expo.sed in niimei'oti.s outcrops slifjjhtly consolidated and eoarse-bedder than the horizont.d Pleistocene silts an('. <;i'av(ds which are exiKised all alonjr tiie<-ourse of tin- Vukon. They maybe provisionally refei'rcd to the Miocene oi' Pliocene. From theii' nature they seem to be fresh-water lake deposits. 'I'he nuii'ine .Miocene sandstones described at Xulato are littoral, as is shown by the ve^'ctalile reuuiins, ripple-marks, and mud- cracks which they contain, .so that at the time of ,heir .'1m.-. Vnl. IV. I>'N« .■-'.i. p. IJTD. m^" Rit-; P liff ill 1!).S (.Kill.OCY 1)1' TIIR YUKON OOI.I) DISTHICT, ALASKA. ycllowisli tiiid lin;lit-ic(l(lisli sands and flays was obsi-rvcd by Mr. McConni'U, and Ihto also tlicy nvcrlic unconforniahly dark shales wliich arc [H'oMably ('r.-tai lis. 'I'lic l>oar l{iv(M' l)i;ds Cdiitaiii abun- dant remains of flora, wliicli were ('xamincd by Sir William Dawson anhii-al position Imvi' a uuu'li clostM- rcscni- lilaiicc to the Miocciio (Wliite Rivori of tlio Cyipri'ss Hills and ncigliboring areas than to the I.araniie with iiieh their fossil flora eorrela.es them. Like tho Cypress Hills lieils. they are i liaracterized by their irrei;iilar (lejiosition, by their slight indiij-ation. and by the birno proiiortion of gravel and ])ebble beds which they contain, and a further degree of relatimisliip is evidenced by the fact tliat they both rest unconforniably on the beds beneath. Mere lithological similarity in the case of two such widely separated cletrital terraiies is of very little vulne in determining age. and in the jiresent instance might be disregarded were it not sujiported by the more iiiiportant feature of a corresponding structural break. In tlie area of thetxveat Plains, and even in tlie Rocky Mountains, tlu^ Laramie is everywhere conformable to the {'retaceous beds below, but sustains a discordant relation to theoverlying Tertiaries.and it has been found that its termination was synchroiioMs with a widespread elevation of the land and the formation of fresli- waler lakes 'n which the succeeding deposits were laid down. At the moutli of the Bear Hivv r, instead of a confonuable pa.ssage from the t'retaceons the Ter- tiary, we have (evidence that the '' inner was elevated and sulijected to a ,)roloiigeil d(>nudation before tho latter was (h'posited. In order to reconcile the stratigraph- ical position of me Rear River beds with a Laramie age. it will tlierefore be neces- sary to assume that this part of the continent was, toward the end of the Creta- ceous period, affected by extensive movements of elevation and depression in which tlie central part did not participate. CORRELATION'. It is the opinion of the writer that the Tertiary beds on the T'oreii- pine, described liy .McConncll, are of the .same ajrc as the 'rwelveiiiilG beds.jus* described. Liketh ' Porcupine J{iveraii(l Hear River beds, the Twelveniile beds rest unconforniably on the older rocks, in this case upon dark shales, which have been called the Mission Creek series, and in which ]\[r. jMct'onnell foundth(> fossil . I (/fvV/a luoNqiien- .s'/.s var. i-oiicnitrifd, thus sliowinfr that they are, in i)art at least. Cre- taceous. The same fossil is found in certain of tlii^ dark shiily rocits which uiiderli(> tlie slitflitly consolidated Tertiary beds on the Porcu- pine. I.itlii .onically and in dcfrree of ii. duration the Twelveniile beds reseiiiole closely the I'orcupine beds, and in both regions they have suil'ored a very slight amount of folding or tilting. All, more- over, appear to be hike deposits. It has already been reciilled how below ,>[ission Creek there o\erlies the heavily folded .Mission Creek .series, in ai)]iareiit conformity, a series of heavy conglomerates ami shales carrying i)lants which are I l)|i. c'it., || IKII) m ^w TIIK I'.U.ISADKS liiNCI.oMHHATE. lll'.l ODiisidorcd by Dr. Km twit on lo idciitil'y I lit- scries ;is of the K nc :[\ii\ Botwci'ii tlit'sc Kdcciic beds of llif Kciiai UTcnii) aiiil llic iicailx lidii- zontal Twclvcmik' beds there is tberelore an al(ril|pt iiiiiMiiii'iiiiiiil y, aud the did'ert'iit'o in dcgrue of eojisdiidation between the two tnnna- tions is so fii'Ciiti tlial in tlio field the ])()ssibility oC their correlal inn, even in a ueiieral way, does not snirj^esl itself, sinee the 'I'welveniile beds appear certaiidy nineh yoimiier. If the Twelveinile and tlie Pori'iipino beds, therefore, are still considered Eocein', wc must accept, t he coiisecinenee, already iiointed out liy Mr. ^fcConnoll, of a judfoiind tinconl'orinity separaf ill}; tlie dilTcrent cihicIis of tlieKoceiic period in this region. Since, however, if appears to the writer that the classi- fication of the i?ear Kiver beds as Ka.aiuie by Sir William Dawson (or as I'lipor Koeono by Dr. Knowlton) rests on data whi<'h, hi>wc\er sn^jfestive, are not finally conclusive, it soems that the evidence atl'ordeil by sf rati.ni'a|)hy and lit holoiry shoidd be considered, and thai at least the ])ossibility of a .Miocene aire for the Twelvemile and I'or- cxipini' lie di\ isina of the ro<'U formations, t hese l)eds must be scjiaratcd from the undi'rlyinu Keuai series, and thoyai'O therefore uutppcd separately in this report. I :1 '. THE PALISADES CONGLOMERATES. On the left bank of the Yukon, about :>•'> miles below (he moulli of the Tanana, clifl's of .silt and ura\cl rise to a heijihl of |."io feet. 'I'liis V'J'*''^*:' feel, the increase beinj; apparently caused by a fault which is visible in the face ()f the bliilVs, and which u[)thrusts the dowii-ri\cr porti(Ui The fault is a normal one, and the silts of Ihe iii)strcam side are seen to be ii])turned atrainst the fault |)lane. (See fig. 11.) On the downs! ream side of the fault there is brought up a lower and more con.solidated ij; ■■ y 200 GI'.OI.OCY OF TIIK YUKON GOLD DISTRICT, ALASKA. bt'il wliicli midcrlics t lie sills. Tliis ikmv bed is i)iiro wliito, hpinjjcom- jmisimI .)f clean sand iiiKJ woil-wiislicd ])('bl)l('S. It is strongly cross- lu'ddi'd. and foiilains inucli woody matlcr— sticks, lojrs, t^tc. — in a condition between wood and lignite. Manyof these woody layers are stee]ily inclined, bcinir cross bcchb'd witji tlie sandstone. This l)ed is very Kent ly arclied and has a liarely ])erce[)lible dip downstream. It is i)artly indnrated, so that while it yields with comparative ease to a pick, it is firm en.nij;h to stand in solid, nearly perpendicular clilTs. iuid falls in ffreat slabs. In the materials <'i)Uccted from the woody layers Dr. Knowlton found fra^nnents of dicotyledon.s, but, none sullicientlly distinct for identifieation. Many of the layer.s are full of finely preserved cones, Avhich, aecording to ])r. Knowlton, appear to be the sanu^ as Heer's /V/(//.s iiiiircJiirIi, and from these he infers that the ago is riiocene, or po.ssibly Upper Miocene. THE YUKON SILTS. i.ii '! Yr'KOX FLATS. ThrouKliDUt nearly its whole course the Vukcm flows throujili an un.iilaciated country. The great eonlilleran glaeiei', which has been iiiaile known <'hielly by the work of Dr. (J. 'SI. Dawson, and which occui)icd liritisli ('oluml)ia west of the Hocky ^[ountain.s au'll, and Hayes. From its source to its mouth the Yukon flows in narrow, dee]) valleys; and where the country has been gla- ciatinl, as along the l.ewes above the ]>ig Salmon ]{iver, th<> hills are •somewliat rounded and the toi)ography suggests gl.cial action. Here also the rivei' sometimes slackens, and forms long, narrow lakes, whose shores are generjilly steep and often in'ecii)itous and whose basins are siin])ly jjortions of the ancient rivei- valley which have been dammed in one way or another. North of the limit of glaciation the seeiiei'y is nujre bold and pietures([Ue, and the river flows through a deep and often liarrow valley with stee]) and rugged walls which are eonsj)icu- onsly terraced, the lower terraces being formed of gravels or silts, while t hi' higher ones are earved out of the rocks. 'Wiis is the nat ure of the valley from the Uig Salmon IJivei- to Circle City, a distance of 4110 miles or more. About ."() or (10 miles above Circle City the valley of the Yukon enlarges, so that there is ofli'n a llood-plain .several miles in width, which is swampy ami covered with moss and .stunied sjjruce and cot- 1 i.SJ : sprnnO THE YUKON SII.TS. 201 tonwood. The cuts iilonu the l)aiik of llic river show that this Hood- plain (l('iK)sit isi'diiiposcii mostly of st falifii'd sands witii some j^'iavcls. Fai'tht'i'down the river the width oft lie xallcy still inc-reasi's. Almut 5 or i) nules above Circle City the sleep wall on the left side suddenly disappears, and is replaced bj' low, perfectly Hal banks, which stretch away to the southwest Jo or liO miles to the distant low mountains. The high rock blult on the ri^dit bank persists a little lon.i,'er, but near Circle City this loo disapi)ears. With tlic recession of the conliniufi rock walls the river broadens out and wanders slowly throufrh the flats, formins; long islands with channels or sloughs between. Thus the Vukoii is said to be 7 ndles wide at Cir(de City, and unr!ig<' of •■> to S feet above tlu' river, and Were composed in largo part of dark-colored silt with some coarser sands ami tine gravels. These higher islands are covered with a heavy growth of spriu'c: the somewhat lower ones, which are nuide up of sand and gravel rather than of silt, have a young growth of cottiniwood. while tho gravel bars and sand sjiits, which rise only a few inches or a foot above the river, are hare or have but a scanty growth of young vegetation. So numerous ai'c the channels in tlH> river that one is rarely con lident of having found the true bank; indeed, between Circle City and Fort Yukon our i)arty was never certain about this point. From Fort Yukon to Fort Hamlin, however, the nuiin current of the river Hows along the right bank, which it does indeeil for the whole length of tho river between Fort Yuk«m and tho si'a, as has already been noted by Kiissell; and in this way the .stream is continually eroding dejiosits which have been >indLslurbed for a long [)eriod. I'.etween I ort Yukon and Fort Hamlin the boatman drifting down the river naturally fol- lows the swiftest current, and tiuu'efore keeps always close to the right 11 m If 1 li' p' /«i 1 1 I *. ^ ^ ^ ' \ '^ ■kh.< ;ff 20-j Ol.dl.DOY OF Tlir. YUKON fiOI.I) DISTKICT, ALASKA. liaiiks. Till' hunks arc usually liit^licr lliaii any of tlu' islands in tlic river, vcacliintr (i'''cn :>n or |o tVct above the water at tiie time of otir observation. Like many of tlie islainls, they are built n|) mainly of horizontally siratilied sill with frequent layers of jrravel. They are eovered witli a thiek ^'rowlli of trees, many of wliieli are evidently of eoiisiderable ayre, and on the surface is a coatiiifj; of deep moss, wliich is not found .n tlic lower islands. 'I'licre also appears 1o be an abscn( f the driftwood ami oilier evidences of yearly inuiidalictn which eharacleri/.c these islan feet, above tile ri\ci'. There is no not u-cable iiarrowiiijf of the \alley as the slreani approaches tliese hills, but the hills lie transversely to the coiiise ol' the river, like a solid wall thrown up to hinder its adsance. I'p to the ycyy point of reaching; this liai'rier the ri\cr colli in lies to be very broad, willi inaiiy islanils. Iioth tlic islam Is and the banks ari' low and ]ierfecily lev<'l, and are built np entirely of u'lavel capped with silt, exactly like the banks and islands for I'.'iO miles above. Tn the silts numerous shells of small f^asteropods were found, belontriii},' to land and frosli-water siiecies. all of which are liviii;; in this region at pi'cseiil, aeeoi'diiig to Dr. W. ]I Dall. Here, ns ffirtlior ii[> the stream, the true banks of IIk- river are higher than the numerous islands, and there is no evidence that they have been inundated by the river Hoods for a long period, since at the time of oliservation they wore about '.io feet above the I'iver, and appar<'iitly above extreme high water. ()!i leaving the flats the ri\'er imme- diately enters a narrow ennyoii, the walls of which rise steeply ui) to tlie general level of the hills. PI. XXXA'I is a ])hotograp]i of the lower end of the Hats and the beginning of the Lower Uamparts. In the right foreground is the silt bank of the river, 'i'lio river, here cutting its right bank as nsiial, is undermining tli(> silts, so that they fall into lli(> water continually, carrying with them their vegetation. In the center of the picture is the narrow, eanyon-liko valley into which the river plunges on leaving the flats, and the level top of the hills in which this valley is cut is well shown. Beyond this level surface are low, rounded hills wliieh rise above the usual lev(d to a considerable heiglit, and in the distance are steeper and higher mountains. Heturniiig now to the upper end of the flats, we find that their boundary on leaving the Yukon runs olf at, a right angle to the river for a few miles, ami then skirts the base of the Crazy ^Mountains. Eight miles southwest of Circle City is a stream of considerable size, known as Hirch Creek, meandering through tlie flats. This stream, however, c(Uitiniies to hold a course nearly iiarallel with the genei'al trend of the Yukon, so that the distance is iiearlv :.'oh miles from this Mi I W' J *l ' -i 'i u 1 I'r M ^1 '"i ■i^n I ;l T'l • 13 ■PURR.) THi; YIKON SII.TS. .'(»;{ |H)iiit to where it Jiiiiis tlie lai'irer river .sDiiie ijlstain'e lieinw tlie irreal, beliil. I'l'idii tlie point on IJireli Creek (lirt-fl iy o|i|)(i>iie I iiclc City the Ihits extend haeivwiiri! in a sontlieas! ilireftion, t'oiiiiinn' a lonir, lii'oail arnL. IxMindeii in' hiuili and hiliy land in all dii-eei ions except, the nort hwest. As is e\ ci'ywlieri' the ease, t he liiM' of Jiinet ion nt' t li(» ilats with the honniHii;,' liiudier land is very dist inelly inarkeii, and lias been followed alon^^ this arm in some detail, since it is in this rcfiioii that the placer ^travels of jiireii Creek, uliieh are ihe most prolitalile thus far diseoverecl in Ilie Niikoii district, are found. ^^'hen thus t'ollowccl, the line is tonnd to he extremely irre;;iilai', liranchiMn' olV into arms w hich run for some distance up \ alleys deeply cut in the hilis. '{'he to|M)^'raphical sketch map of the Mirch Cr ^ek iiiinin^r district ( I'l. I,) ,L;ives some idea of the Junction of these j-'lats with the siirroiindiiifx hills. The bottom of the Ilats et ween this swampy eouiitry and the base of the boivlcrinj; hills is a b(dt several miles wiib-, which has a uniform, very slij;lil slopo awa.v from the liills and which is ordinaril.v dry. Tiiis belt occupies the mo.st of tho valley of Crooked Creek above lloj;"eiii Junction, and has also boon continuously observed aloiij;' the base of the liills botweoii Central House and tlio Twelvoinil(> caclio. (Soo PI. .\I,IX.) The surface of this belt exhibits very slijrht undulations, which are not noticed in the perfectly level countiy m;ain, is also very stroll;; e\ idea f the existence of such a body of water, for at the Junction the canyon-like valleys suddenly and completely disap- pear and tlio river wanders farand wide ovei' the sandy deposits, into whieh it has cut the merest indentations. Tile belt of ^rently slo|)inu'. coarse, sli;,ditly stratified material, more- iiver, which has been described as lyin;; between the swampy lowland and the hills in the iiii'ch Creek mining:' district can be accounted for only bytiie siijiposition that it is composed of torrential material, hrouiihl down by the mountain streams which have carved such deep valleys in the surrounding hills, and deposited alon^ the shore of a shallow body of standing,' water. The materials of this fi'a;.M>ieiital deposit, as has been remarked, corresiiond with the i ks found in the valleys of the inounlain streams. .Ml the central portion of these flats, which 's remote from the Khores, is of fine malerial, chielly silt, \\ the uiesentt iniethe \'ukou rises annually into floods, iind o\erlow ishiiids deposits repent oil layers of fine sediment, which ill many cases have . ■ciiiiiiilated to a thick- ness of several feet. These recent llood-pl.iiii i'.i']iosits are often not disi iii;;iiishable from the silts which form the banks of the river, but the latter ordinarily form blull'sof ;;i'eater hei^cht. Thetfrowth of low islands by yearly additions can be studied in detail alonu; this jiart of the ^■ukoll. and the evideiii f ^rrowtli is generally seen in nuincroiiH layers of woody or i>eaty matter, which alternate with the layers of silt and represent each a suinnier's^jrowthof ve;retatioii, whileilielast layer is i|iiite fresh and is only partially covered by certain rapidly jtrowin^j' [ilaiits. The presence of driftwood and the marks of recent ^routriiiu; by floating;' ice are also freiiiient evidences of late inundation. In the higher deposits along the banks, however, the .silt is frequently very I X(it<"i i>ii tlu' siirfac ifi'olKKy <>f -Maskii: Bull Oi'ol. S.«;, Ami-ricii.Vol. I. p. 112. 'Ann. Kept, iivul Xiit. Hist Survey OmiKiii. lSSN-««. Vol. IV. pp. 2TD. 1;BD. TlIK VIKON SII.TS. 205 111 irk, lias Hull' evil Iciicc ul'^i ralilic'iil idii, ami i> « i! limii i Ih' iimiiic'ichis lilllc scains of wcmhIv niallci' wliidi mark tin annual nmwili nf i|ii> lower islamis, wliilc llic sill liH'r is il('c|)l\ con cicil wiili luuss ami liill- ;;ro\Mi I lees ami hiislii's, ami has cn idi'iil ly iiol I n llooilcd lor a \i'iy Ion;;' period. II seems eeiiain, llierel'ore, I hat if these latter are llood- plaiii de|)(tsits. they were formed at a time when the irt-neral level of the ri\'er was hiuher than it now is, or lie fore ii li.id eiii mi i lei ply inio itseliannel: and from the eharaeters nieiitioned it seems |irolialili- that llieyare lake sediments. .Mr. I{n>.-'ell has siiir^,'esleil that the w hole material of I ho Flats is a \ ast flood-plain de|iosil, spread mil liy I he Yukon in eonseinieii f the river ha \' in;: been dammed up liy an elevation of I he lianiiiarts, I tut tlieal)i'U|il terminal ion of I he upper end of the Hats as well is the lower end, and the e\ idenees of shore-lines alreail,\' ;j;iven, seem to exclude this hypothesis. Coiicerniii}; the Hat deposits alon^r the lower part of the roiciipiiie, Mr. .MeConiiell ' remarks: This iilaiii liiis ii width in it.s wiilest jiart nf t'liUy !io mill's. Siotiniis arr (.'iit tlirniiK'i it i" ilill'iTi'iit iliroctiiiiis liy tlic I'linuiiiiii' anil Pilly-Yilkoii. anil sliiiw it tn hi' unilorlain thnnifilnmt liy Htratifinl sauils ami silt.s, otirii slmwin;; falso bt'dilinf,' ami with iiccasional layern nf gravel. Tim latter aii|ii'ariiil tn lic'iuno filler Kraini'il and nf Iuhs relativo inipnrtanci' tnward the ci'iiter nf the area. Tho size nf the iilaiii. its iinifonuity. and the I'haiacter <>f tho lieds which iiiiderlii' it, sUKfii'st a delta nriKin. ami cnrrelate it with the Inwlands at presfut in course nf fiiniiatiiin at the inniith nf Slave Kiver, in Great Slave Lake. The period at which this lak(! e.visteil must he \ery r nt, for the fossils ;"oiiii(l ill tho silt all belong; to liviiij; s])eeies. Another piece of evidence is foiinil in the sliy-lit anioimt of erosion which streams have iu mplished aloiij; the ed^cs of the basin. In the /one of ni;,\|.|s and lorrontiiil iimtoi'ials, which has been described as borderinjr the old shores in tho liirch Creek district, tho stroanis which How from tho moiiiitaiiis run in constant, narrow cliannols, yet they have cut (iidy iiioro furrows, which can not be detecled in a ncnoral survey of the landso)ii)o. The samo phenoiiionon was noted in the Lower Kaniparls, below Fort Ilanilin. Tin; river hero flows thronyh a narrow valley, with steep walls, which aro distinctly terraced all the way tiii to a nearly level l)lain <1(H» or 70n foot above Iho stream. In those walls lateral j;ul'i"s runninji at rif,'ht angles to the main trend of the vaUey have bo^nin to form, but they aro so iniporfcct in thoir dovolopniont that they must hfive bcfinn very rocontly, for the most marked ones aro only (loop V-shaped notches. Another snjrj;estion is ollVred by the |iosi- tioii of tho river in tho flats. Tho erosion of the ri^dit bank from Fort Vtdion to Fort Hamlin is very rapid, and it follows that the stream niiist bo ra|)idly pnshinj: northwestward. The rapidity of tills prottress can be fully a])preeiated only by one who has traveled 1 Op. lit., p. j: u. I:. ;tH IM l>()(i (ir.oi.ocii- OF THE vrKON (ioi.n disthict, ai.aska. tihma tlic l>;itik of lilt' riv.T iiiid hciinl tlic t'oiiliiiiial splasli of the water, willi llic ruiiililiiif,' of the sill hanks and Ihc cracklin.ir of Irces as the nnik'r-cut porlions fall. Al lliis rale il is .vidcnt llial in a very shoi'l, time tln^ slrcani will have ])nslicd its way I'losc ui) to the nortliwcsterii border of tlie ilals, and the fael that it has not yet done so is evidence of llit niparalively brief jHiird that it lias been workini;-. Tlial it lias already traveled some distanec is liinted at by Ihe fael that il is al iiresent a|)|)ro.\iinately Ihreo times as far iTom the southeastern side of llie flats as from the northwestern side. I'OKT IIAMI.IN TO MVNOOK (KEEK. About lialfway between Fort Hamlin and Ntynook Creok, in the vieinitv of b'ay Ki\er. tlie vall(>y broadens out. formini; low Hats, wliieli streteh S or in miles away to low niounlains. wiiieh are dis- tiiiftly and evenly tenaeed (see 1"'. >'L). Kelow this iioint the river makes a sharp turn lo the left, as shown on ilie map. and enters a narrow \alley. Ojiposile Mynook (reek are narrow Hats aiiaiii. (>n the left bank of the ^■uke.l. Just abo\e]Myiiook ('ri'ek, is a irreat tliiek- I'.ess of steeply diiijiiiiir Kenai bods, as alrea'!;. desi ribeil. These arc exposed in a steep iiliilV about (01) feet hiiili, of whieli they constnilto tlie lower l(Miorl'0i1 feet: uueonforiiiably overlyinji them are ."i or 10 feet of hori/onlalh' bedded ui'avels and mud, and then :'i«i or odO feet if sills lil those loiind 111 Ihe Its. In I'lese sills fossils were lected, which were ideiititied by Dr. W. II. I>.lll as Si/ci-imd fln'ijsi. \Vest.. \'iilfitl(i sliici rii Sa\'.. an d LiiiiiKi (I jiii /(/.S//7.S Mull. All these species are found liviiii;' in the reirion at present. .M"N('T1(1N dl" TANAN.\ ANH VIKdN. At Ihe end of llii' Lower Kamparts. Just Ihe moiilli of the 'rjinana, the river auain broadens out into flats. The banks here aiH- of liorizonlally slralilii'il silt, often .'!b, 40, or even do feet above the water.' I'"roiii the ri\er these flats extend in perfect uniformity on h side 10 or b"! miles back to the hills: but iliev narrow fariher eai down, till about airain cuts on its miles below the mouth ol I'-iiiana the stream iirlit bank the hard schists of the liirch (reek fi lion. Melowlhis, however, th(> silts coiilinue • expo; ill pi: especially on the left bank. They are al.so said lo extend up the Tanana for niaiiv miles, causin;: islantlv sliiflinir i-haiinels like those of the Yukon I'Mats, and reiulerinL; stejiniboatin;;' diflicult. Lieii- leiiant Allen - notes that below the Toelat l{ivor the Taiuma becomes vcrv wide and si iiiriiish, with sometimes ■iCNeral eliannels. Th ind( the manner in which il enters the Yukon, the various bran.'li- in^s havinir the asjiect of a delta. Aliciut till' 1st .if Si'|il..nilHi- ■ Ht'pfU't nf all Ex^H-dition to tin* t'tipi)rr, Tauuiiu. aiiil Kcyukuk Kivrrs. Suttutc IJuc. l-'.">, 1.SH7, P.M. ^»^ TIIK VIKOX t^II.TS. 2' 17 About .ir) miles liclow the 'I'aiiaiia, on llic left siilc of the Viiknii, rise i)('i'i)('niliiMilar Icvcl-ldijpcil hlutl's aboiii l.'iii IVi'i in liriirlit. 'riic inalcrial in tlicsc h! nil's is niostly cxli'cinfly line sill, irrciMiisli-irfay In color, I'oi'niinij; when wcl a tine, sticky clay, ami sliowiimscarccly .iny traces of stralifical ion. Al inlei'\ als in Ihis deposit ,iie thick IkmIs of vi'^etahle matiM'ial, containiiiir wood in all sta>,'es of cliaiiire. from ])lial)le sticks to hrit lie Ill-own liiriiite. Tliesi' beds vary in thickness and also in the nature of ilieir material: usually, howcM'i', they con- lain trees, sonieof coiisideralile size. .\l the hejiinninudrilie exposuie, ami for some distance farther on, one of the heaxiest beds of woody inatiM'ial is from (i to iio feel below the toj) of the blulf anil is about 4 feet in thickness, while diri'cl ly above it lie mixed L:r;i\ els and sill, with occasional sli skeleton of a mammoih was founcl, and 1 usks and other bones of this and other mammals are so commonly found here that, as has been said, the locality is known amonu the nunersas the 'Mioueyard," altlion,u:li it is \)\\\ down on li.cniapsas ihe Pali- sades. \ tooth pl(dr end of these blulTs the sills and lipnilc beds are dls|)laced by a sti'Cp fault, lia\ Ini;' a throwol al)onl •"ill feet, and by this the up])er bed of the I'alisades connlomeiales is bi'ouirht u|) below ttie silts. The contaci of the coni;loniei-alcs w ilh the sill has a sliirhl inclinat ion downsi rcan'. showinu' .i scarcely per- ceptible liltin.n'. (See \'\. WXIW) These blull'sare beiiii;' conliliually nndei-cul by the i-|\ei\ and yet Ihe clay is so lirm that the ii|(i)ci' ]iart of t'le bank often stands out as a ])i'o,joctiii,u; slndf when the lower pa'", has been carried away. When Ihis lop part linally falls, theiefore, it does so In i^reat masses, and scMuetiines sinks ,nia breakin;,', and lodui's al the fool of the blulV, where lh(> trees which 11 bears still continue growinir. Al Ihe upiierend of the sill exixisures a lai'irc iiuiss, con- taiiiin.n' ])art of the iipi)eiiM(Ht l-fool bed of lljfiille above referred to, has sunk down in Ihis manner. The lijjnite in the fallen portion has taken fire ami lU'arly burm'd out, altlimiirh in plai'cs it is still smok- infj ar.d hot. TIk' ti'aasformalions ellVcted by this bui'ning in the suri'oundin,u' materials iire curious and inter' si iiifr. lu llu' unb\irnl lliinite are layei's rich in boj;' iron ore, which (Ui burninj;' is fused Into a sort, of impure pi,u\ Other portions of the (day luue been fliseil into vesicular slaj;', resemblinu' lava, while a little f; ther away from llio burnt seam bright-ied bri(dv has been formed, which is exactly identical in appearance witli artiliciar brh'k. ( )t her port ions of the clav a.ssume varhnis brii;l;t color-; m dilTerent stages of the baking m 'rw I i •JdS (iKOI.OGV Ol" THE YUKON GOLD DISTKK T, ALASKA. pi-ocfss i^rccii, (iiiilini'. yellow, and ii'd— aiid llii'st- baked clays often sliow heaiitil'iil leal' iiiii)i('ssioiis when l)r(dieii open, wlileii can not he diseeiiied 'n tile unliiniil slale. On llie lace of the lilull' tVoMi wlileli ilic mass coMlainln^ the buni- inn' liyiiile seam lias fallen the same seam is exposed 1(10 feel or so lii^dier up. liiil liere it lia> not been on life. In a search for the reason whv the liu'iiile in tlie fallen mass should have caiijrht lire, while that, remaiiiinu- in t lie blulV escapeil. Ihe only iinporlant point ofdilTerenco whicl nld be discerned is Ihal the fallen i)iirl of the s* .im is covered 1»V waler every year, while that in tlii' bliiH' is (piile out of reach of the river. In spite of the yciirlv inundation, the llres have been bnrniiifi; for a very loiii;- period, as li'arned from the iiali\i's and miners, and it seems possible thai the water may have been the actual cause of tln^ combustion. The iirocess may depend ipoii cliemical action belwcen wat.iand some of the components of the silt or liirnile bere covei-ed with thick moss and are free from evidences of recent inundation. At various points, moreover, beds of silt having the - me appearance as those now being formed by the river have an >ilL tude several hundred teet or more above the present stream, and p. sometimes as much as 200 or 300 feet in thickness. These eh^vated silts are evidently of greater ag! than those Ij'ing only a few feet above the river, but there ir a grad'ial transition from he higliest to the lowest, showing ti-at in the Yukon N'alley nearly the same sediments have beendeposite*! during i. i)eriod in which the river has cut down its bee' considre forimvl under lacustrine eomlitions in time of 18 UKOL. I'T 3 11 210 C.KOI.OliV or THE VIKhN (lOl,;. .USTlilCT. Al-ASKA. (looil, aiiil lilt' slcp t'l'diii line to llic ollifrcinidit ion is vci'V sliirlil. 'i'lio < li'\;ilcil lii'ds of pure silt ill .MyiKiok ('roclc. Ilic I'lilisadcs, hciow tlit> Siioiikakat. and al ntlicr places aloiiir (lif rixci', scciii 1ss of these deposits is also airainst the idea of river deposit i ,ri. SI I. IS ItiriWKKN I.AKK 1 AN AM) Tin-: I'lVK KIN(ii:H HAl'lDS. On the Lewes liixcr. above the junction with the Teslin, is a series of lonu'. narrow lakes. (See IM. XXWII.) Four of these, iakes I'iK l:.v \*ii\\ at ilif hfuil i-i' Ljikf I.iniit'niuii. Inukin^r w.-st. slmwiim tin- hiu'lifi' i k .iit T(-iTR<*i'. its t.)i> 'MitUiu'il l»y Mi;(iw, . I Ml tilt' saiiu' 1>'V.-1 us this is tin- U'^jiiuiiii^r oi a ltroaly slij;lit simdiciit, wliicli fcadn's lnuk sniui. .lisf.-iini. Irum tln' lak.' rivnii tlio It'Vi'l nf tin- riM'k-ftit torrat'c tlir wjitiTs pliiii^f smlcU'iily dnwiiwanl. aiul liave <'arvi'il u ^inall caiiyi'ii Liiiileiiian, IJeiitM'tt, Ta^iisli, and Marsh aic closely coniu'cled and have nearly the same le\'el. Lake Lebarjre is .somewhat o\'er -lO miles lolly, and is separated from the rest by (id or 7iMiiiles of lajiiil river. Li is llie lowest in (he series, beinir some .'in miles aboxc I ho iiiiinlh of the 'reslin. All these lakes occupy iiortions of the old, tleeply eroded river valley.s of the \'iikoii and its tributaries, wlieio «.| il i9 I USGtOLOGICAL SURVEY EIGHTEENTH ANNUAL PCPORT PART i!i PL.VXXVIl FairweaUier ^mJ*t litu ,a lev! apt'*v .-% 01 njNE MM' 01" Till-; ri»i»i;H yikon and \i(1m'I"iai)AI'ti:i,> i'hom co.vst sruvi:^ ciiahi' t Siiili- III null--. --=»L-._ . te^ Arrn viilloys liavc hcoii ohsti'iicti'd (ir (li'I'dniicil so as to (Imti up the (li'iiiiiajfc. 'I'Ik' liver, wliicli (pccupics its did \,illi'.\' Itdnw llir lakes and between Lake I,eliari;'e and Lake Maisli. is at ihcsimiI mi \ lapid aM cut by small valleys of consideiable depth. (See li;r. 1-.) Tin' lower tcri'ace, therebire, seems to In n- strnetional. and to have been bnilt up in ipiiet walci's. while the ll[)[)er ont' has the a|)pearanee of ha\ inu' bi'cu carved out of the rock l)y a body of wali'r capable of sweepinu' awa\ 'he rock frairnieiiK as fast as tlu'y were worn from the hills. On Lake Tajiish and Lake Marsh there a I'c blnfVs of tine. lioMioi;e- noous silt, horizontally St rat ilied. J(i or :!ii feet in hci.uiit. Thai pari of the Lewes River which connects Lake Marsh with Lake l.eliari;e is known by the miners as Si.xlyinile IJivei', it beinii' appro\iiiiaiel\- of this lenuth. On the upper part of this river the sill bliilVs are :lii or 40 feel hiiili. and they gradually }j;row liifjlier farther (lown the si ream. About halfway bet ween f.ake >birsh and Lake Lebaruc I he ri\er \ alley has been dammed by a (low of basalt. throUi;li wlii<'h the sireaiii has cut a mirrow caiivon where ihe water Hows very swiftly, .lust below the canyon are the White Horse Hapids, which are analo,u;ons to" the eases already described alongthe Yukon between Circle City and the sea, and notice- ably in the Flats bet ween Circle Cily and Fort Hamlin, where ,sedi- iiionts of nearly uniform appearance are found at slijthtly dift'erent elevations; and of th(>se the hitrhei' ones were jmibably laid down in old lakes of considerable duration, while the lower ones were deposited later, at times of Hood or temporary damiiiinff of the river. Lake Marsh, wliicli lies above Lake Lebarjie, is called by the miners I ■*' THK YUKON SILTS. 213 ]\Iii(l I.iikc, (111 iH'J'oinil of its slialliiw, iiimMy lidtidiii .iiin slnn-i's. Ili'fo iifraiii I lit' scdiiiiciils arc exactly like tliosc ot' t he liiirlicr lil nil's, ami ilio process of tlu'ir formation is like lliat at Lake Leharue. in the hul- toiii of tiic lake tlic silt, aeciitiiiilatious must Ix^ very tliieU. The exposures of sill in lilull's cease, so far as uhsei's I'll, at the <>xtremc u[)|)cri'ncl of Lake Lcliar>fe. The shores of this lakt* wliero exaiiiincil were lai'^cly of haie I'ock. At the lower end of the lake the Lowes River at first flows through hanks of gravel ami sand .ii) feel or less in heiijht. Below these u'ravels there is (iricii exposi'd clay containinj,' pclililes and snlianirular howlders, Ihe deiiosii beinii' evi- dently of ji'hieial ori;jrin and ha\iiijj: ordinarily the asjieci ol ,i trim till, llioiifrh often showing signs of sir 'irication. Near the Jnnelinn of Iho Lewes with the Tcslin this glacial dei)osit, capped Ky gravels and intcrbcdig Salmon iJixcr they aro often entirely of liuoly stralilied matoi'ial, and are still as much as 1011 feet ill hoight. The silts conlinne to he expose(l, allernating Fkj. M.— Diaj^runi sliowiiiK folding in silt liluffs ou the Iji'Wuh ahovt! Miles C'anyou. with frequent rock oulorops, nearly to tlic Five Finger Jiapi silt beds and I'csting nnconforinably on them where they have been plicated. This layer is never more than a few feet thick, and is often entirely wanting. On top of the river gravels, or, where these are wanting, ou lop of tho silts, is e\ cry- vvliere seen a thin layer of white, gritty volcanic ash, which ordinarily conforms to all the little irregularities in the sui'face, and which, there- fore, has the appearance of having been deposited a comparatively i* 'I :.'14 (;i;i>i.(i(iv ov iiik vi'kon (ioi.u Disruicr, Alaska. sIkhi tiiiii'Myn. '11 lis Nulciiiiii'jisli is widely disl li lint ci I nvcr I Ills por- lldliiir Aliisi-.a, iiiiil liiis Imm'Ii (Ic'sciilMMl hy nciiily all I ia\ I'lcrs who liavi' |ia->c.(l iliroiiy;!! Ilils n'yimi. Aloiii; this part i>f the river llii> lavfc is iH'MT iiKne than a few iiiclws tiiick.aml is inn liatcly nvi'v- laiii li\ si'vcial iiichi's (if \ cuctaliii' Inain, "liii'li rcifiiis the iiMnicilialc sni lai'i'. Till' stca'lv increase in elevation of the lowest liroail sill terrace" from the lakes to the I'alikeena Kixfr indicates that tliesnrfa< f this lowest terrace is \(>ry nearly liori/onlal, mo that the rixcr. in :-.il- tiiijidown Ihrouiili it. Ilows hetwi'en hi^jhcr and hiy:h('r liaiiks as it, reaches siiceessi\ely lower points. It is prolialile, Ihcr'cfore, that this deposit was laid down in still water or in a scaiecly |)erceptihle enr- reiit.and the iiatiircof the sediiiieiils. which are like lhos(> now I'orniinu: in Lake .Marsh and in other places under lacnst riri iidit ions, points to the same conclnsion. So far as ohservci!, howc.-er, t he cont innity I't' the silt deposits appears to he broken at the upper end of Lake Leliar^e. At the lower einl of Lake Lehai'f::*' arc low lianks of howl- der-clay and j^ravul: licdow tlie month of the Teslin tlie liowlder- ' lay liecoincs ea|ipcd by an incrcasinir thickiu'ssof silt and gravel, md the filaeial material appears to pa.ss laterally into stratilied dcfiosits. 'l"he hoifjht of the banks also increases soniew hat, althoiiiih not so markedly as on Si.xlymile River between Lake .Marsh and Lake Lcbarj;e; however, between the niontii of I, itt le Salmon Kivcr ami l'"ivc Kin^jer i{apids the luterbedilcd sill and line gravels are sometimes e.\|)oseil in porpendieiilar blntl's lot) feet in heiitht or more. These deposits often bear evidence of the e.vistence fo'- lonj; periods of nnifoi'Mi conake lA'barjic, and had probably in places .some ciirr.'iii. Aceordinn' to aneroid dctcrnunat ions maile by Dr. Dawson's i)arly, the surface of Lake Liiidcrman is 7l) feet hi;;hei' than that of Lake Lebargc, the elevation of the former beiiiii' lMTh feet aiul of the latter :.',UHi feel above the sea. The main gravel ami silt lorriice (ni Lake Limleman was estimated by the I'liited States (ieologieal Survey (larty as being ."iD feet above the lake, which would give it an altitinle of J.JJii feet, .lust above Lake Lebarge the broad silt plain through which the river cuts was est imatetl as being more than l.'iO feet above the water, and is thcix^fore at an appro.ximate elevation of l',i'.5ii feet. This elevation is :iit feet aliove that of the Lake Lindeinan terrace. It must be rcmemtxM'eil. however, that the elevation of the lakes as • Ictcrmim'd by the aneroid can be only ap[)ro.\imatc, and. moreover, that our own estimates of the height of the blntl's at the various lilacesare m'cessarily inaccnirate. Careful surveying might make the i\i\-- lllile Kiv er, .lllil (III llie I, I'W es Well-ma llieil liellelies, « ji ji'li (ieelll'l||i til a eiiiisitleialile lii'iuhl. |)i-. hawsiiir e^timaie^ tiie lilu:lie>i ii'f- iace> nil Lake l,el(aii;e as lnii iVel alH(\e the laki', while I'mlessuf Unssell- pills their heinlil at .'i"'!! or I'lim iVet. On the li.uer |iarl nf Lake IJelinetl the liiylii'r terraees were e>t iliiati'il li\ the uiilei a> lieilii;- li"i cir .'iiii I t'eet alii)\ c t he uater. < Hi Si\t \ mile Itiv er. Iiet weiMi Lake ALirsh ami Lake Leliar;;e. t ln' two Itesl-marki'il terraces were measiireil with an aiierniil liy Mr. Sehrailer ami t'oiiml to lie 17"p I'eet and ^iiiii I'eet alidxc I he river. Tile il|i|ier one w as lii'>l iiiaike(|. (t|' lllese sllee('ssi\ e terraces the liiwesl are in ;;eMeral the iiKJ-t regular. uikI are iiiad)' up iil' silt, sanil, and ;ri':i\<'l. Thi' upper (iiie>. uhieh were mil earel'iilly e\atnined, are imire irie^'iilar in dc>lail. and nl'teii liaxc the ap[iearaiiee ul' lieinn- rnek-ellt. alt hciliudl elielimliered with j,'ra\el and sand. On Lake r.ennett lieiiehes Juii oi- .'inn feet alnixe the lake are s'rewii with lar};e ;;laeial Imw Iders <<{ ^'lanite. w hic'li li,i\ c bi-eii hrciiijilit friim a jioinl soini' miles up the lake. The oecui'i'L'licc of tcri-ai'cs or lienelies i^ liv im mean-- limiteil to I lie v! iiiity of the lakes, for Ihey \verc> oliservecl all aloni; ihc ^ iikon l{i\er lietweeii here and the sea. They liaxc iieeii miled al many points in .Maska and llriiish (oliimhia liy(;. .M. Daw.son and K. (L .Me( oiinell, and are foiind on islands in Ueiin^ Sea. 'i'hese terrai-es will lie spoken of in more detail later in eonsiderim: I he movements of the land, and il n I only lie staled here that the whole interior plateau of Alaska and lirilish ('olumliia ajipears to lie distiiietly ter- raeed up to a trreat hei.irht, wiiieli may he ap|iro.\iiiialely staled as ;!,lll)(l feel above the sea. Above this oeeasioiial terraces are fouiiil up as liiiili as ."i,.!iio' feel. .\s pointed out by Dr. DawM.ii. Ilicso hijiher terraces are disliiicl from Ihe abiiiidanl river terraces in that, they do i;,it alwa.Ns follow the river valleys, bi.l skirt tile di\ icies and appear far up on the liiiiiicst hills. They seem lo mark the former shore-lines of a ifreat level body of wali'f wiiicdi Hooded the whole counlry, and from Iheir |iresence in such places as the nioiin- taiiioiis islands of jierinj;' Sea it is evident that lliev are marine. From Ihc clearness wilh which they are ordinarily cnl, iiioreo\er. ji is evidiMit that llicy were formeil at no very ancient ucoloyieal perioii. For these reasons Dr. Dawson has coiisiilcred the leriaces, which have been described, above the lakes on the I'pper ^■ukoll to be of marine orij^in. Evidence found at other places shows that the sea probably eiicroachefl lliiis far al least, and when il stood al tliisideva- lion it must have formed shore-lines. The characler of the upper lienches on tin' lakes, such as the bench described on Lake Limh'iiiaii aljove the yravel terraces, favor.s the idea tif marine origin, for I hey I Ann. Kept, (lecil. Nut. Hist. Sui-vi'y t'liiincla. IW ■•«. V.il 111. I'iiit 1. p iviji -Xotps on till' siirfiu'i'K'i'iiloKy nf .\liiskii: Hull. (frol. S«<' Aiin'ricu. Vol 1 p, li;. "G. JI. Uawsmi, Trans. Uuyiil Sue. L'iiu:iUii, WJU, Vul. VIII, Si'c. IV, [i. :!•>. L'li; (ii;i)|,(M;Y or TIIK YI'KoN (JOI.P DISTUICT, ALASKA. ;i|i|M'iir I" 111' ciiiNcil mil 111' ilii' licil-i-cick, ami siirli ii iiictlKMl of I'orina- tliiii involves acli\c rfosiou anil iicIIm- ri'iimval ahseiice of inariiie fossils in the silts, as Dr. Dawson himself [loints oiit,^ is nef,'a- tive evidciii-e a;;ainst consideriii},' I hem marine. The assemhied facts wiiich have heen cited seem to ]ioint to an explanation inlermediate lietween the dilTeriiij; views. The benches or terraces all o\er the interior plateau of Alaska and Uritish Colum- bia, frinjring' the mountains and the inountainoiis islands in the sea, point to a Notes 1111 till' surface tteolrifty of Alaska- Bull. Oi'^il. Sih:. Aiufrifu, Vol. I. p. Hi). 'Trttll^s. Koyal S.ji'. t.'uiiailft, Vol. VUI, Si-l-, IV. ji. -i;!. 'IIIK VUKDN SILI'S. 217 jjoiiif; (III ill Alaska. In lliis case llif cause ol' ilitViTfiilial iiiii\ I'liii'iil or ri'lalivr (Icprt'ssiuii may liavc liccii, as sii;;y:f,'«ici| by I'lofcssor ]{iiss('ll,' the wcinlil ul' till' irri'al ccirdillcraii irlai'icr. 'I'll!' approxiinalc cniiicidi'iicc of llic iKirllnTii ImmmIci' oi' uhK'iatiiiii ami lit' tlu! Hilt depoMilM in this rc^rlnn seems tn Cavnr iliis li\ iMiiliesis; lull whatever may liave 1 ii tlie eaiise iil' its (iriiriii, it is eeriaiii lliat. a liasiii was t'lirined aixl si ill i-xisls, ;iii. Here the silt, deposits are siiceeeded by rock shores, and at the fool' of Lake Lebarf^e, where silts and <;ravels ha\ in;; the apju'ar- aiK'e of laeustrine orijfin are aj^ain found, they are at a lower level, iiidicatin^r a somewhat sepai-ate and deeper basin. IJelow Lake Lebarf^e the silts frequently indicate lonj;-eoiitinued seilimeiitation in ([uiet waters, l)nt the iiiorainal material found aloiijr here has caused irregularities in deposition and variation in the nature of the se(li- ments, so that the charaeters of the deposits arc by no means coii.stant. The narrowinj; of the old valley in this rejrion is likewise adverse to uniformity of sedimentation. The lower body of water below Lake Lebarj^t,', f time they will shrink to still sinailer ilimeiisioiis, or vei\ likisly will Ix' entirely drained, in whieh event tiie iiresent shore lines and tlie silts aeeiniiii- latinj;' on the bottom of il>e lakes will he exposed aloiijc the banks of the fntiii-e river in sill hluIVs timl terraces identical in a.ppeai'aiice with Ihirse now roiind, and foriiiiiii;' a 'latiifal e(iiiliiniatioii of them. Another faeior in' the (haiiiiiii,'' of the lakes was probably t i It in;;. So uni'at an elevation (probably at h'asi ij.oiio iVct) was not witliollt .some slight irre;;iilaril ies. Indeed, on the Lower \iikon and its trib- utary st reams, it appears that the land is beinj;- ele\ ated more raj (idly to the south than to 1 he north, so that the streams crowd over to their northern briiks. If this dilferenl i.d tdevation extends to the rei,'iou iif the I'liper ^'^lkon lakes (where time was not available for investi- {ration), the drainage of the lakes innsl be accelerated thereby. .Moi'o- over, if. as has lieen sn,u';.^ested, the depression of the ancient ri\er \alleys. forniinir lake liasins lliroUi;hoiil this rejrion, was eaiisecl by a sinkinir of Iheeirth's ci'iisl 1(\ the weitrht of the cordllleraii ulacier, this same rcirion should now be f i:ainin,u: its former elevation, and in doin;i' so the water aceiliniilated in llie depressions would itradiially be dischartred. That there I;ave been local dist iirlianees diiriii!.': t he proi'ess of elevat ion is show i; by t he slight (ilicat ion of tiic silt ImmIs and liy the occasional faultiim'. INTKUmi! I'l^AtKAl HIKJION (II" UUITISH COHMltlA. I)r. (;. .M. Dawson has describe!!!id», l»r-B«,Vul. UI, I'liit 1. 1). l:>ih THE YUKON SILTS. 219 1 TKSI.IN ItlVKK. Oil till' Tosliii (IliM)t;iliiii|iiii) l{i\fi'. Dr. ('. W. Ila\c>' iKitccI ron- tiniioiis Icvcl-loppi'il hhitl's, cciiisistiiiii iiiiislly iif sil',. willi laviis of sariil which .•ire cit'tcii I'loss-hiMldcil. Ilii' wliolc lii'inir ciippod li>' a l»'il of coai-se tiravcl in Icct m- iiicuc lliick, wliicli is shaipl.v cpaiati'il from the I'liidcrlyiiit;' silt turiiiatiuii. The hliiiVs iin-rcasc in hciirlit from inn ft'ct at F.akc Aliklcn to {."infect at llic nth of ihi>ii\ci-, anil arc fi-ci|iiciitly cut inio a ininihci- of terraces. KdWAK (I, AYS AM) i i i:olM>-l( I'. I'nliM .\Tli iNS. rmlcr these heads Dr. NV. II. Dall ' has dcscrilied a series of clays, with often interstratitied beds of ice. which occur at \arions points on the .Maskaii coast, notably on Koi /.el, iic Sound ;ind the Kowak lii\er, as described by I.ieiiteliailt (,'aiilwell. Alonii the shores of the .-.ea and the banks of the river there are e.\i>osed in inan\- places dill's of simIiI ice, V. hic'li sonu'tiiiies rise to a liciuht of l.Mi feci and are co\ereil bv clays and da;k-c()lored earth, on the lop of whicli lioiirish trees and moss. This ice tlierefoi-e plays the part of a rock forniation. The clays also occur in ]ilaces where the ice is absent, and on the Ko -ak HiYcr forii; in one jilacc a bliilV tliree-i|iiarleis of a mile lonsj; and I. "in feel hiirh. ( »n Kol/.cbne Sonml. a' Klcphant I'oint. the beds of blue clay contain nniiieroiis bones of ricistoccnc man. nulls, such as ti.;- eh^pliant. h.or.se. and bnlValo. and in the Kowak I'lays are also nian\ niamnuilh Insks. Dr. Dall describes some of the clays at Kle- pha.n I'oint as containing;- iiiiich vojiolable matter minirleil with the clay or foriniu.ir distinct layers in it, and in one laver of spliau'iimii or boii moss fresli-walcr shells of the eem.ra I'isidiiim. N'ahata, dc. were found. These ice and clay deposits are considered by Dr. Dall as li:i\iii;' lieeii foi'incil in vast shallow lakes, and are referred >oniewhat ilollbtMllIx to the rieistocelle.' I iil{|{Kl,AM')N. Tn all the localities which have been descvibed are deposits of silt havini.' similar <'haraclers. showing' deposiiioii in liod'-s of still and ,.i'te-i iindonlitedly shallow waler. These sills ofle ; contain the reii..(iiis of the mammolli and olher I'lcisloceiic in ^unals and land and fresh-water shells of living species. Wood am. \ci:eiable inali 'f are also abiindanl in pl.ices. In most cases it seems ceilain that the bodies of waler in which the deposits were formed were fresh-water lakes. The silts of the rjipcr \ ukon and the siirroniidiiii; re-ion ha\e been supposed by Dr. Dawson to be deposits in iiiai'inecsinarics; I Kxpriliti.iii thl-otn-h IliM Yilkiili ilistfirl: Nut. i "■">;. Man. V.,1 IY.|. In'i '' Bull V. s. ii....l Siirvry No. »4, Cori-olatloii l'niiur«-N.'."Oiu-, |j. am.'t -fii ■>0\). tit.. 11. :;iiii; al:1 220 (JEOI.OGY OK THK YUKON GOLD DISTRICT, ALASKA. but iit i)ios<'iit tlicrc iiri' iiniiu'roiis lakes in this foimtry, and the raised iK-aciios aloii^' tlio coast and the rapid down-cutting of tiie i-ivcrs in tlic iiitciior slmw liiat formerly those lakes must have been more extensive, so that part, at least, of the silts must be of lacustrine origin. Considering tlie problem of correlation in the light of dynamic dis- turbances, we lind that most of tlie silts wlien carefully examined sho\ve\idenees of slight movement. On the hikesof the I'pper "^'ukou tlie silts are in iilac<'s slightly but distinctly plicated, so that the later river gravels rest on them \\ii!> slight local unconformities; in the Palisades the silts have been displaced by a fault of 5U feet, while on the Lower Vukou evidence of tilting is sometimes found in the incli- nation of the surface of a silt deposit which must originally have been horiz(jn1al. In no i)lace, however, have these deposits met with any important disturbance. A(iK OF THE YUKON SILTS. The silts on the Lewes and Felly rivers rest upon bowlder-clay, showing that they were deposited in places left by the retreat of the glacier after its maximum extension. On the other hand, abov(> the silts comes a layer of river gravels which tnarks the ])oin( where tlie elevation which first caused the retreat of the sea Ijecame sutli- cient toconvei't standing or sluggishly moving water into rivers. The lakes of the Lower Yukon were also formed sabse(juent tothe retreat of the sea, and were also draine(l in con.sequence of the increasing elevation. It may be said in general, therefore, that the accumula- tion of the silts began in shalhtw lakes and sluggish rivers on the emergence of the laiul from the sea after t ,ie n: iximu n extension of the cordilleran glacier, and has continued on a progressively smaller scale u|» to the present tlay, since such sediments are now in |)rocc.ss of formation in lakes like those on tlie Lewes, in sluggish parts of the Vnkon and lis tributary streams, and on the (lood-plains of these rivers. The gradually lessening amount of accumulations is due to the increased elevation of the land and the consequent in<.'reased carrying i)ower of th(> rivers, whereby the silting-up of the river beds is prevented and the channels ai'e cut down so as to drain the water fiom the old 'akcs. In the L'pi)er Yukon region tlio silts seem to have been largely derived from material ground out of the rocks by glacial action, and this material has doubtless contributed very largely to the sediments of all the lak<'s into which waters rising in this glaciated region empty, t'oneerning the origin of these lake basins, it seems likely that slight, dill'erential movements in the earth's crust were the most com- mon cause. The elevation of the whole peninsula of Alaska for .'(,000 feet or more can hardly have taken pla<'(> without occasional irregu- larities, the hitesl evidence of which are the slight folding, faulting, 11 H'rim.i THE AXOIEXT GRAVELS. 221 jukI tilliiiirof tlio sills. Very sli.'iht local diffoi-oiioos wmild convert portions ol' the okl river \allcys into lakes similar to tliosc now exist- insi in the I'pper Yukon region, and in such lakes most of tiie silt deposits seem to liave f'ornieil. 'i"he broad Itasin of the Yukon Flats, however, can hardlj' \h\ considered as havinj; formed jiari of ilie ]h(>- Gliieial valley oriln^ Yukon, since it. stretciies out abruptlx from the junction with tliis vall(>y to a jrreat width. It is [lossible, therefore, that this is an oro<;cnic depression of considerable ay:e. Other hypotheses have been made to accoiint f(U-1he orijrin of t ae Upper Vukon hikes whicli furlhei' study may sliow to be in i)art or wholly correct. T)r. G. M. Dawson' snjj;g:ests that "the lakes of this reiiion now (tecupy the place of the last loii<^ues of the fireat jrlaciei-, wliich in the end disappeared so rapidly that their beds had not time to become filled with detritus." Tlie same view was held fo: Lake Ahklen by Dr. t'. W. Hayes,- who consiih-red that ''the present lake basin was doubtless occupied by a lobe of the retreatinu: i^lacier, \\ liieli prevented the silting-up of the portion of the valley so occupied. On the withdrawal of the fjlaeier at the close of tlie stationary period the lake was leftinuch as it. appears .it jiresent, only somewhat larui'r, its wat(>rs beinii' held by the dam of silt which had been laid down in f.ont of the ice." Prof. I. C. IlusricU ' sugfiests as an e.xiilanation foi- the origin of the body of wattnMo which he gave the name of Lake Yukon, that the river valley must have been obstructed and dammed iu some way, possibly by the large lava-flow at the mouth of the Pelly, or by morainal material deposited along the nortlnjrn der of the cordil- leraii glacier. Profe.Sior liussell, liowever, holds an .si ill more prob- able the hypoliiesis that "the weight of ice forming the tfnat cordilleran glacier was sufHcient to depress the ear.h"s crust i the manner suggested by students of glaeiatioii in other regions. As the !<•(> retreated the dejiression thus originated was occupied by a lak. , wliich was slowlv drained as the land regained its former elevation." THE ANCIENT GRAVELS. ANCIENT Kl)LU-;U (iUAVELS. The silts of the Upper Lewes in the vicinity of the lakes a.e over- lain by a few feet of river gravels, as already described, and Dr. liayesMuis noted a similar deposit on the Teslin River. All along till' Yukon Hiver aic terraci's at various heights, and on these are rolled gravels which aii' said often to yield gold in small quan- tities. The successively higher terraces spread o\cr broader and broader areas, so that it is ju'obable that the distribution of these I Ann. Uept. Ooul. ITat. Hist. Survey r-anailn, Vol. Ill, Part I. IHHT-**. p. IKB. 'HxiiiTlitiim tliiMiiL'li tlio Yiiljon DNtri.-t: Nat. (t.-.m Miiit.Vnl. IV, ji. ."nl. 'Nnti's..!! ilii'Mirf.icvgeolntsy "1 Aliwka. Bull. OudI.Soc. AiiiiTl™. Vol. I.p. ll.>. <0|i. cit., p. l.")il. 6i ■;'■ k m ■!3 222 ni-oi. the ri\ er. 'I'lic same iieolonisi reports that aloiiu the Slewari Ki\er tlier(> is a constant reciiirence of hiirh i:ravel terraces, most of which i.i'c more or less'aiiri*' • .is. Althoiiiih I he uiiiM'ls (Ml the lower i ' ver terraces are ilonlitle>s duo to stream action, ihose which arc more i wliicli lie on rock •\ated, and esiiecially those ■cut hcnehes, iiiiist he due in lai'ire part, to marine ai.'lion; or, if iriuinally river uraxels, must have lieeii redist rihiiled liy the sea. for these upper le\els have not l)een .sub.ji'ctod to river erosion for a loiiij period, while I'll in late ueolouical times iliider tl an watiMs. We may therel'oro exji till • ii'iavcls tl be almost nuiversally found below a heiniil of .'>,oiiii feet almxcthe soa. in places where they have not been stri|)ped olT by recent erosion. AM 1 1; NT (ill.Cll (.1: W |;Ln. In t he bottoms of the nari'ow^ii Idles u liich led i he lai'irer si reams the acciimiilat ions consist chielly ni' anu'iilar rock t'raj;iiieiils, uhicli slide down from the steep ^;ulcli walls and form a deposit that shows little of the sort ill jr and weariiii; ad ion of water. These deposits are therefore ilisli net in nature from the well-rounded jrravelsof >hc larjjer streams. .\s the jiiilches wear down their beds, portions of the older aecumiiliitions are soiiidimes Idl on the sides of the valley in ii iiiaii- ner analo^ions to the I'ormal ion of the uravel terraces of the larfier stream^. Thus on .Moose (reek a deposit made up of angular and subaiiiiular iiebblcs ami bowlders of schist, sehistoso ^raiiili and iliiart/. occurs in the bottom of the \alley and on its siiles up to a lieiKlil ofsexcral hundred feet. The deposit shows litt le evidi-iice of 'Ann. H''iit. ili'^l. Nut. llUi, Siirvi'V Oininla. V.il. IV, 1M.SH-WI. p. L'Tl) sri'Bii.l VOLCANIC ASH. 223 sort inn' .v wjitcr, llic t'r;i,u'iii''iits liciii;.' itilcil tii^'cthci in sucli lu'lttT-skcllcr rasliidii Unit no sirat iliciiiion ran lio made- mil ; the material seems to he plastered uiiln liie scliisi tliroimii wliidi ilio valley eiits, and is sullieienl ly hard to Iniiii sharp ridui's anii of the iipjier ^■|lk()ll i iiere ipcenrs, nverlyinn all other dt'liosits e\ee|il a I'ew inches of veu^elahle hiam. a bed of \(ilcaiiie ash. This ileposil has been meiil idiied and described bySchwatUa.' l>a\v- siin,-' Hnssell, ' and Hayes.' Ahmu' the I, ewes this ash occurs as a line, while powder, in a layer oiilya lew inches in thicl'> or 8 inches. In S(iiii(> places there are two distinct layers, of which the upper is direct ly at the i;rass roots and is com inuoiis, w Idle the lower is a fool or two deeper and is separalc(l fi'oiii the upper one by a fool or two of siratilied ri\-eri;'ra\ els. The lowei- layer is iiiteriuittcnl and often cross bedded with the aravel. and is Iherefore walerlaid. Some .'iO or 4i» miles below the I'ixc I'iiiirer Rapids the ash irrows vcrv thin, and is scarcely noticed at all below the I'elly.' Oii ilie \Vhiie Kiver, howmor, it wasfonnd by Dr. Hayes in immense (|uantities, a tliiekncss of "•") or b'K feet beiiii;' sometimes observed. Accordiiiir to Dr. Hayes, the eriiplion which fiirnishe'iit RiVLT, Xew York, ISW, p. 11"., - Aiiii, liipt. ilc.l. Xnt. Hist. Siirvi^y. Caniiiia. Vd. 111. Part I. IsxT-hs. pp. 4^1. 4tlB. '' Xoti'soii tli.'MU-l'iii-i' t,'i-i)li.ny .if .\lasUai Hull ()i'..l. Sn.'. .\iiu'l-ii'a. Vol. I. p. IW. 'ICxpoilitioii tliri]iii.'li the Vuk.iii.listrirt: N'at. Ui.otf. Man.. Vol. IV. ]■ llil. •''OnChi.-ki'iiCn'uk.Ht tli.< li.'ail of Fortymilo Oi'.'k. this ash is fouiul .,ti tho surfaci'. Init wan not iiotoil ill thi' lowi'i- parts „t Fc.rtyiuilo Cri'ok This is iu uci'orilaii™ with tho iclwi of its diTivatioii from lli'ar tin' iipp.T part of tho Wliito HiviT. U'lt i»*i .Jl I • !•' m c]^ APT Y.n T 1 1 . IGNEOl^S KOCKS. Two sets of isriioous rocks haviiij: widosiJiead distribution and dofi- Bite iiositiun in the gcoiojrical (•oiuiiin, and so possessing llu' same value as stratified rocks in the study of structure, have alreadj- l)ee!i described— the basal granite and tlie effusive diai)ases of the Hanipart series. Hesides these igneous rocks there occur in the gold belt many dikes and also later volcanies. It is now jjroposed to treat these igne- ous rocks as a whole, passing lightly over those already discnissed. BASAL GRANITE. Granite is the oldest rock yet found in Alaska. In the Fortymile district it is found underlying the ([uartzitic schists of the Birch Creek series, which form the oldest sedimentary series known; it is also found along the Yukon between Fortymile Creek and the junction of the Lewes witli the Pelly, and along the Pelly to tlie Dease River, as described by Dr. Dawson. According to Dr. Hayes, it forms the prevailing mck of tlie greater part of the region between the Yukon and tlie St. Elias jVIountains along the 'Wliite Rivei', and according to Lieutenant Allen and prospectors it is exposed for a long distance on the L^pjier Tanana. It thus forms a continuous belt, running in a northwest-.southeast direction. This belt has been observed for a distance of not far from 800 miles in a straight line. On both siiles of the granite, to the northeast and southwest, successively younger strata occur, so that the exposure of this I'ock seems to lie along the axis of a geanticline. So far as observed, the fundamental granite is usually more or less schistose or gneissic, having undergone tlie same mountain-building stresses which have converted the overlying sediments into schists. Locally this shearing becomes so great that the granite itself is con- verted into mica-schists. Where moderately massive, the fresh rock is of a gray color, and often contains porpliyritic crystals of feldspar, which in the more schistose zones become lenticular bodies or eyes. In the slightly weathered rock the color changes to a red or brown, which is cliaracteristic of most surface outcrops. Under the microscope the rock is seen to be made up essentially of quartz, orthoclase, and biotite, all coaivsely crystalline and with a typical granitic habit. The orthoclase or niicrocline often occurs in large, [lerfect phenocrysts. Accessory minerals, notably niuscovite, calcite, epidote, garnet, micaceous hematite, kaolin, pyrite, and chlo- rite, are .sometimes found in large amount. Some of these minerals 224 s ^i hii'hr] DIKF, R()( KS. '>•)■ arc derived from the docoinpusitioii of llio foldspai- ami mica, wliilo otlicrs rc])rc,scnt const i-iict ivc pruci'sscs wiiicli lia\c liccii cipii.scciiicnl upon liic slu'ariiii,'. Tliis slicaiinir lias also operated td luiaU and stretch tlie ori^rinal miiKM-als in ;;ivalcror less dey;ree, yet the granitic nature is usually ([uite nnmistakahlo in the held and almost invaria- bly so uinler the niicroscoj)e. l-'i'oni this fnnilamental granite must he disliniriiishc(| ihc ii'usivo frranite, which is of later ajje, and occurs frequently in dike- .r Icusos throughout this portion of Alaska. DIKE ROCKS. DIKES IX THK KOHTVMll.l': DISTRICT. Dike I'ocks ai'c e.\])oscd in varyinjr dei;reo of abundance over most of the irolil belt, es|)ecially in the older formations. On I'"oi'lymile Creek, however, tiiey ari' found in remai-kablc abundance, and hero also are esjiecially oihmi to obscrvat ion, since continuous exposures are oH'ored alonj; the walls of the canyon-like valley which the stream has cut in late jj;eoloiri<'al times. The relation of these dilfereiil dike locks to one another can therefore be carefully si udied, and as the nbseiva- tious made in this limited area need not necessarily a])pl,\ to simil.ir ro(d >llier dikes have been .sheared ihroUi;hout, but notably less tl .u the sedi- nuMitary rocks; others still have l)een sheared only locally, \\hil.> a <'ei'tain class hav(> experienced no dislnrban<'c wliale\er. These | he- nomeiia can meau only that the dikes were intruded at ditVe/enl jieriods, and that the devidopiiu'lit of sehislosity was not smldeii, bul, occupied ]U'obably a vci'y lonu: time. A convenient, if somevhat arbitrary division, based on structural features, may therefore l)o nnide Ijetween the dikes which have been most and those which have been least slieared. This is really a classilicatiou belwciMi the older and the yonufjer dikes, since those which are most altered were evi- ilcntly intruded i)revious to the chief development of the schist<'S(3 structure, while the unaltered or less altered dikes came in at a some- what later period. r,Aiii.u;u scnisTiisi; i>ikks. Under this head are considered only those dikes which have been so much altered as to become virtually schists, they having' exiiericnced l.S OKOL, PT 3 15 '^ 1 , i I i iir, M .11 2'J(i GKOLOGV OF THE YUKON GOLD DISTRICT, ALASKA. practically tlii' saini- iiiiioiiiit of iiilcistitial iiiovfiiicnt as th(( iiiolosiiig Bcliists of sfdiinciilary ori^iin. 'riicsc dikes arc not all necessarily coiiteini)oraiieoiis in oiM<;iii, hut all are older than t lie niaxinuini period of sliearinj;;. Moreovei,', there is no sharp lino of division botwoon them and the dikes whicli will he considered later, for there is a per- fecl transition in de^rree of scliistosity Ix'tween dikes which are com- pletely sheared and those which have snlfercd no movement. Qiiarf.~-(liiin'li-sili/.sl. — Oi\ Fortyndle Creek helow Hrown Creek the lower Jiart of the wail of the so-called "c:inyon" is made up of a mottled schistose rock of a K«'"<''"il dark-j;rcen color, which inclo.sos eyes or short .seams of crystalline (inart/.. Under the microsc()|)e the rock is seen to have the j4;rannlar structure, and con.sists essentially of quartz, feldspar (|)la},'ioclaso predoniinatinjr), and hornhlendc. There is also some hiotite and .secondary epidote. Pyrite altering:; to hematite is not infreiinent. The wlioii' rock has heen sheared, and in places the minerals have heen };ranulate(l. Dioritt- (IV si/cnlte-NfJilat. — On I'ortymile Creek helow the Forks are great ma.sses of a dark-green rock with schistose structure, which, howe\-er, in places becomes coarse and massive and cari'ies lartto phenocrysts of hornblende, lietween this massive rock and the line- grained schist there are all stages of gi-adation. Certain pinises also contain mncli hiotite, which takes tin? place of hornblende. A s|)eci- meii of tliis schist, .seen under the microscope, ajipears to have for the predominatinji mineral orthoclasc, much mnscoviti/.ed; also some j)la- gioclase and (piartz. Fresh brown hiotite, very likely secondary, is present in large quantities; and colorless e])idote, in sniall crystals and in irregular grains, forms a large proportion of the rock. Diorile-jM/rphi/rij-scliisf. — ( )n the South Fork of Fortymile Creek are large areas of hornhlonde-.scliist, some parts of which are fine-grained, while others become gradually coarse and develop slim hornblende phenocrysts. Thes(> phenocrysts are usually arranged in a racimen of one of the liner varieties of this dark-green schistose dike rock shows under the microscope jihenocrysts of feld- spar, whicli are much altereil to epidote and calcite. The groundmass is mostly orthoclase, with plagioclase and green hornblende. There is also consideral)le ejjidote, and iirobably a little quartz. The few o.Kamples which have been cited show that the extremely schistose dike rocks of the oldei' .series appear to he dilTorent phases of the diorite family. A few dike rocks from other localities which Hi' HI si'rim.l DIKE ROCKS. 227 I liiivc experienced the same amount of sliearinj;, and are tliorofore probably of the same age, will be described later; and it ai)i)ears tliat, so far as observed, they are all varieties of the granite and diorito families. LATEIl USSHEARED DIKES. Most of the dike rocks which occur so abundantly on Fortymilo Crock are only slightly or not at all schistose, and often cut directly across tlio schists, so that they are evidently of later age than those dikes whicli liave been altered at the same time with the inclosing rocks. In these dikes there is a marked variety, and the difl'erent rocks seem transitional into one another, so that all stages of change are represented from extremely acid rocks to extremely basic. EXTHEMKI.Y llASlt! IIOIKH. Rocks of this character are abundant, iind are present in dikes of considerable thickness, also in nuuicroiis small dikes and stringers. They are nearly black, and often coarsely crystalline, and so have a striking appearance in the field. They are usually (|uile massive, with no appearance of schistosity, and yet sometimes slmw evidence of disturbance by the presence of joints and small faults. Pijroxenite. — One phase of the extremely basic dikes is l)lack and usually coarsely crystalline, with finer-grained, greenish bands. Much jiyi'rhotite and other nic1alli(! minerals are recognizable in the Iiaiul specimen. Under the microscope the structure is seen to be coarse and holoerystalline, and the rock to be made ui) almost wholly of green or colorless augite, with a small amount of green hornblende and some brown biotite, in irregular strips. Some of the augite shows zonal structure. Pyrite and pyrrhotite are present in considerable quantities. There is no (piartz or feldspar. Another dike whicli appears originally to have been of pyroxenito is altered so as to consist niostly of librous serpentine in radial, parallel, or felty aggi'cgates. In the serpentine are numerous lem- nants of augite, from whicli it is undoubtedly derived. Magnetite is present in moderate amount. Ilornhhndite. — Another dike having nearly the same appearance and the same habit as the pyroxenite, and occurring so close ;o it that the two are probably varieties of the same rock, is found under the microscope to consist essentially of green hornblende with very abundant epidoto in crystalline prisms and irregular grains. Pyrite, pyrrhotite, and ilmenite are present in large quantities, so that small pieces of the rock are readily attracted by the magnet. No quartz or feldspar is present. In the hornblendite are nai'row bands of bright- green rock, which under the microscope are found U\ be made up entirely of epidote. These bands have probably formed along .joint planes. Similar bands are found at the contact of the hornblendite with the aplite which cuts it. 'M' ^i * rffa m L'-28 OKOLOOY OK THE YIKOX fiOLD msTRICT, ALASKA. /'ii/iiiiifiHc Imnihh iiih-i)inlliiiji-liii>lili ,iirl;.—{)\\ KinM yiiiilc C'rcok almvc Siiiilli Creek IIiimc (iceiir slici'ts aixl ci'oss-ciitt ilijr ilikes, iirii'ii l.'i (.!■ I'll feel ill lliii'Uiii's>. 1(1' ii scry coarsely ••rystallino (lik(» roek, which is made up of iiiiiroiinly iai-,i;e crystals of horiihleiule, pyi'oNeiiile. anil iiiica, iiilerv'r')" ii in i)e;riiialiti<' fashion, eaeli eryslal l)einf,'aii inch or Iwo in Icn^rlh. A specinwii lakeii oT Ihis roi-k i- sisls appili'enliy of iilioiiioiphic cr\stals of horiihieii(le and liiolile interj;ro\vn, each crystal liciiii; alioiii -1 inches in ieiijilh. On account of the c.\lr(!inely coarse texture, only a single crystal was shown in the sliile, ami this was taken from a slijiht ly ilitVerenI portion of thu rock. It consists of ilijilla;,'e with po'ciliiic struetnre, containin;; man\- sniail in<'iiisions of brown ami i;rcen liiotite, ami crystals of hematite or ilmenile. INTKIIMIJIIAII: lliH K~. /'o;y/(///'/7/c liiinilili ikIi-si/i iiilr. — 'l'Uix rock is dark-colored ami basic ill appearance, contains mueh pyrite and pyirhoi ite, ami also many jicrfect crystals of feldspar. I'mler the microscope^ the strnc- tliro is seen to lie nearl\' |ianidiomoipliic. The roek e, since they occur close 'oi;etlier in a series of dikes of flic .same a^e and the same apiiearauce, and since one seems to pass j;i'adually into the other. {liiriilili nth -ijnnilli . — This rock < urs in irreat dikes in the inarblo of the l'';irtymile formation. It is dark-colored and j;neissie in appearance, an (' csst'iil iiill.N a Inic ^ranhi' with |iIiimiimm\ >ls nl IVid- spar. siiiiill ami impi'ilVctly (lc\ c'ldpcil. 'I'l NM'iitial cuiisi it iicnis ail' iii'llniclasc, (|ilart/., ami liDiiililcmlc with sdiiic liiotitc. 'I'lic scc- (imlai'v iiiiiu'i'als arc ciildrili' ami cpicldic in cdiisiilcralih' ipiaiilit irs; aisd lieiiiatitc, I'alcitc, and aiM iridlitc. Mairiii'liic ami iliiiciiilc aid locally ahiimlaiit. The iiK'k has tlii' iiiiiiciai cdiisi it iicni'. nf ^iiuiiic. ami .\t'l Ihc proportidii of the (IIITcrciii iiiiiici-als is such that the incU is decidedly liioic basic than l> pical y;ranilc. I'lii-jihiiri/. — A specimen taken IVdiii a iliki' nn the ri"''"'l y:ray color, with phcnocrysts of llcsh-cdldicd I'dld- spar. I'nder the microscope llm phcnocrysts are I'onud to lie iiiinh allereil td milscdvitc, lull seem to he nl' prcddininal in;,' drlhdchisc will) some iila.n'idclasc. Areas df chldriic prolialily represent driy:iiial phcnocrysts of hiotite. The ;;rdiindmass is tine-nraiiicd ami holo- ci'\ stalline, and seems to he maih' up chiclly of orthoclase. (pmrl/., and innscdvitc. (Jidirlz-dliirili , or (/riiiiniHiirili . — (In the rid;;e heiween l'"ianklin (iiilch and Chicken Creek is a ;j;rcat dike of coarse-irrained rock which lias the appearance of an aeisciitial cim- stiluents. Titanilc and ma;:iielitc are yi'iierally [irescnl. In smuc jiarls of Ihe I'ock inici-dyraphic intcrurow I lis of (juarly. ami fcldsjiar occur. Arrii KIM KS CI rtiiH/ir iijilili . — This rock is liyht-^ray in coldr and line-^riaincd, and dcciirs as a nai'i'dw dike cutliui: nidii hasic dike idcks. I'mler Ihe inicrdscdpc it is seen to he made up chiclly of drthoelase and (piarl/. in lar;;c hypidiomorphie ;;rains. Some iilayioclasc is iiiteiMrrown with the ortlioclasc. (Jrcen lii. Oriliinirii (iiililr. — Abumlant aplites are fiuitul of a very li}i;ht-f;ray or pure-white color, consistinj; essentially of orthociase, tpiart/,, and pla^'ioclasc. Small ki'"''"* '•' i'"" p.vrite ai'c usually present. Tlu* tc.xtu re varies from coarso to very line. The structure is j;ene rally panidiomorphic with extremely fre([ucnt mici'oij;raphie intcrffrowths, and is occasionally fj;raniloiil. Piiriilii/rilic tijilih. — This rock cuts the hornblondito which has already been described, and thc(,'ontacl lietween tho two is mai'kcd by a narrow band of liornblendc-epidote rock of a bri.uht-j^reen color. 'J'he aplit(! itself is li^ht-;,'ray and resembles a line-jiraine(l ([uartzitc, except that the filimmcr of snuiU fcldspai' crystals can be sot>n hero and tlioro. Under the microscope tho nu)slr strikinfj; miiu'ral is feld- spar in nearly perfect crystals; it is usually orthociase, but. sometimes plaj,noclase, and .sometimes both intcr;i;rown. These crystals aro seat- tore(l I'athcr spariuj^ly through a tfroundnuiss which consists almo.st exclusivelyof (pmrtz in small, interlocking grains, and so hasthooxact ap|)caraiico of a lino-grainod ical ])egmatite, such as is so common in areas of granitii; inlrusivos, was found among the dikes of Fortynnle Creek. As already noted, however, tho aplites vary in texture from extremely lino to so coarso that tho rock miglit be con- sidered fine-grained pcuinatite; and yet the transition is gradual and without a[)preciablo change in composition or structure. In some rocks, liowever, tho (piartz and feldspar tend to separate in distinct bodies, so that large bunches of nearly i)uro quartz occuir, while in other portions of the same dike the rock has the appearance and Hl-I MR.] UIK1-: HOCKS. 231 striicturt' of a oonrsp-graiiUHl aplito tir liiif p(';riiiatitc, hciii;; inail<' up of i'i'!j;iilarly iiilerf^rown crystals of (piartz ami IVldspar, wiili rarely a little liiotitc. iViiioiiK the feldspar's of tliesi aise roeks plii:.'ioelii^« Is precloiiiiiiaiil In some eases: in others ortluielase. 'I'lieie is ^'erier- ally a small amount of ealc-lto vuinin);, and in the liuire masses of (piartz whitdi occur in these (li':es are frecjiient small ;,'eodes, the \miI1s of which are covered with (piart/ crystals. Qiinrlz veins. — The pej;matite or <'oarse aplitc just deseril>e usual coarsely crystalline, iiilcr- lockinff structure, and besides ([imrtz contain only a little ma.!;nclitu aud pyrite, with some calcite vcininiic which Is i)robabIy secoudar}'. iti'.LATioss OF i>iifi:hi:m' V Aiiir,Tri>'. Although tlic rocks which have been deserilinl have l)een classilied under dilTcrent names, according; to their mineral composition, yet as a matter of fact neither Held nor laboratory st udy can (li\ide llieia into aii,v classilication otiier than an artilii'ial one. <>n the contrary, the,v form as a whol(> a <;onnected .series with ordinarily the most per- fect and firadual transitions connect in;; the widely ditVerin;; extrenies, and in this series the lin<' dividing;: the rocks according: In established classillcation.s must be arbitraril.y drawn. It thus happens that in the rocks who.se mineral composition warrants their beiiif; classilied under one name according to an established nomenclature, the rela- tive proi)ortion of the coustitiienl minerals varies so that thei't> aro greater actual ditTerences than there are between some of the.se rocks and others wliicli, on account of the sligtitly dilferent proportion of tlie constituent iidiierals, have been classilied under a dilferent name. For e.\-am])le, there is a p;reater actual dillVrenee in stru<-ture and composition between the acid and ba.sic varieties of the rock wliicli lias been classified as liornblende-granite than between the basic hornblende-Kranit(> and the hornblende-syenite or diorite, or Itetwei-n tlie acid granite and the aplite. Sogroat were the dilliculties under which these abundant aud highly interesting dikes were ob.served that only about twenty specimens were collected. Yet in these twtMity specimens, which were taken at dilferent times and under circuinstances where there was little oppor- tunity for comi)ai'lson, hardly any two are alike, and the set const i- tntes a nearly perfect transition from the most acid tr) the most basic varieties. Themostabrupt change was from hornblendite to extremely basic liornblcnde-diorite or sj'enite, and between these tworo<'ks more gradual transitions were noted in the fiehl. 'I'he nature of the trans- itions will now bo briefly sketched. 2.'1- (iKi>l,iP(;V Ol' Tin: VI'KDN l,l) DlsTiaCT, ALASKA. ■|'li(iii(p-i liii>ii'Viiri"ty isc(iiii|M)MM| sdiiicti >cnl iiclyof Iioi-h.'IcimIc, .s()iiii'iiiiM--nri)\ ToM'iiiii'.iincI xniicliiiK'Mif iMiili i 11 1 fiiii i iiliIimI, all.! <-iiii- tiiiiis ,1 iciiiiiilasicily. 'I'licM' basic r.ifks I tunc |)iM:iiialil ic, willi [Ki'dlilic siniclurc, aiitl (ln's«' p.irliiiiixiiiiiaiii liiuiiic as well as iiyroxcnc iHiil lionililrinli'. In (iilici- localilii's -lik.'s haviiii; , .■ same iMiaisc. i)aiiiilii"_'iii tocariy crystals of I'dd- ■spar. at lirsi \cry spaiiii;:l.\' ami liwii in ;:rcalcr aiiiDiint. In smiio \ariclics iiiiart/ alsn comes in. In oilier places Ihe iKi'iililenile liec!-, ases in aniouMt pr<>porlioiiai..\ lo llic iiic-r. se of IV! Ispar ami iHiart/, so llial llie lock In comes lirsI a lioiiihJcMcl. -syeiiile or dioritc, ami ilii'ii a lioriil)lenile-iri'aiiite or i|uarl/-lionil(lemlc-iliorite, oi _iaii- oijiorile. 'riie lioiiililcmle-;;ranllcs ami ilioriles seem to irraili' iliti) one a mil her in I lie same ilikcs. ami occur in imnii'nse iiii iiisix •• lio.lios, often several miles wide, forming; piolialily a er<''il<'i' bulk than eillier the more acid or the aiore hasieof I lie a lie d rocks. In iliese j;iiiiiites and diorilo !lie hornlilenile -lill I'oni iaiii'- lo he tl Iiief prominent dark Irisilica'i'. alil ;;li bioiite. wliicli was noieil as lieinu one o' tlio I'oiist it iii-:i's of I !;e e ;tsses intc a rock of t'oai'st- or line liypidio.norphic jiiaiiiilar stiiielmi'. composed esseii- '.ally of Miiart/. and feldspar, the predmiiin.int feldspar beiuir ireiier- ally (111 iioi'lase. somei ii.fs plairioclaM^: !heri' is also ssji! ssential liioi ite and occasiotially mnscovite; yet ! Iiese minerals are in sc.-illercMl plai( - "f Very small si/e. In the next sta^'" Ilie mica disappea .s aliiiosi etilirely, beiii^r found only in certain ari';is, so that the rock b mes entirely of i|iiari/ and t'eldspar. 'I'liere is also a leiiilency In cliaiip' from the ;.M'anit 'c to a paiiidioinorphii- si r net iire. and I he n.iii- erals form peirmatoid or microLrrapliic inter^'row t lis, 'I'Ik'si' nick.saro soiiietimi's very liin' u:ra'ned. and soineiini 's are coarse lik<' uranites, I till all ha\ e esseiii i.il!'.' I lie same -.I iiicl lire and con isilion. and lia\ <) been cla ilieil as apliles. I 'I I liese apiile-. the ch,ini;c cinit iiiiies by t he relalMe increase of cuiai'lz and < ■crease of 'enispar. A remarkablo jiliase uttendini; this is a rock eonsistiii;; of scaltcred iihenociysls of feldsp.ir w itli a ^roiimimass of line (|uarl/. in small iiiterloekiiiK^'rains, w liicli has in the lie hi and iimler the microscop" the ex:icl appearaneu of a tiiie-;:rained (|uarlzite. In coarse \arieties of the apli..- both (piarl/ ami feldspar I me nioi'e coarsely ci'ystalliiie, so that the roek ajijndiK'he.s pegmatite in si riicl lire The next st ago after beeomiug m n niKi; icdiKs. •j;<3 coarsely crvt-lalliiii" is I lit- si'|)ai'ai ion >>\' I lie two iiiiiii'ials iiiici ilisi ind areas. 'I'lic i|iiai''/-l'i'lils|)ar ilikeN cuiilaiii laii:c liiiiicln-- nl' mviily jmri' i|iiai't/.. which lias all lln' chaiactcrisi ics uf vein (|Man/. Willi the |)i-cpi.'i-essi\(' increase in acMily the leidspar hecduics reslnciiil in cerlaiii parts et' the \eiii. sonieliiiio iireixiijarly ami si.iiici inie-. cdl- Iceliiii,' near tin- wails, while 1 he pin'c i|iiail/. Iie> in the cciiler. I'inalh' the felilspar (lisapiiears allcitiCther. ami I lie \ ciii ln-ciiiiics pure r|iiail/, Willi oeeasiinial |>ynte, ami now aiilal 'it Ki.iiitc. Olleii lliere is also ealeile, especially aloiiu: the walls In one aii lie seen in all its slajies. In all these rocUs. however, Ihe alisein I' coai'se-graiiieil pe-rinatite is not icealile. In ail Ihe i-ocks. from the hornlilemliles ami pyroxeiiites to the acid apliles. I'piilole I'orins a const ani and i in port a lit iiilneral, lint is in most casi s of secomlarv orisjin. ('onsiilerinu- all ihcse dike rock> to;;ellier. llieli, we lind thai lliey are all made up c>>ciil iallv of a coniliinal inn of ipiarl/. fi'ld>par, and hoinlilemie, with siiliordiiiate liioiilc and ot her rarer iiiiiierals. liy i he di 111 rent icuporl ions w Inch thcsi^ minerals In ar lo one aiioiher in ililVereiit dr. -s all the chief rock l\ pes enmueraled are produced. When the three chief minerals, ipiarl/,. feldspar, and hoinlilemie. with snliordiiiale liiotile, occur in alioiit eipial propo -i ioii>, tin- rock is a hornlileiidc-uraiiite or diorilc. i'"idiii t his iiileriiiediate pliasi' varia- tions are produced li.\' the increasiiiir aliniidan f basic iiiineialsti the cxeliisioM of acid oiie>. or li\ llic reverse proi'cs^: . thai li\ casv slajics one cMiciiic is reached in a lui-k eoiisi>tin,u eiilircly of horn- lilemli and other dark liisilicat«'-«, such as pyroxene and hioiite. with lai-iic ipiaiilities of nielalllc minerals, and llie other e\ireme in rocks consislini;' cut irely of ipi.trt/ and feldspar, which liy incicisiiii;' ai-idity {.craih into (piart/. \eins. nia.A ii\ i: M.I lolMVMMI hiKi:~. 'riieie are I wii criteria lor determining I he relal i\ c a;:es of the I'orly- niile dike*. The lirsl is the one uliich dcpciil-. upon I he oli\ i yoiinuer in at;e. The. oi In >■ .■epciid> upon the rcla- live aiiioimt of schistosily which Ihe \arioiis dike roi k-. show, the seiiis'osilx- lieinn' Ihe record of d\naiiiie forces which lia\c o;ieralcd diirini;' a more or less cMcmled period, and w ho^e iiia\iniiiin nx'ta- nniiphism is measured by the allcral ion into schist> and niarlilcs of tlr^ sedimeiilary beds of Ihe l''ortymile series. When dikes ha\c experienced the same amount of metamorphisiii as the iindosini; sedi- nieiilaries it is certain that they existed in l!ie loek w hen dynamic disliiiliaaees be;:aii; and, on the other hand, dikes whidi show no slieariii , whatever, bill form nia^'^ixe bodie•^c It iiiL' across the schis- M WT '^ f.v u ♦ '23A UKOl.OCY OK THK YUKON (lOLD DISTIUCT, ALASKA. lose roi'ks, were not ])roseiit (]ui'in>: tlio jierio'.l of iin'(iiiiiori)liisin, ami so must 1)1' distinctly yoiiiijfcr ilian tiic slicai'od dilvcs. Iiitcrniediato between 1li(>se oldest and youn^jest dikes ai'e some wliieli iii'o sliy:litly slieaiu'il til roil jriii 'lit, or are locally schistose and locally massive. These must have been inti'iidcd diirinu: the jieriixl of iii<'tamor])hism, so that tlicy havesiifVireil only the tinal el1V• in immense dikes, and beinf; somet imcs u:ieatly am! soinctiiiies sii^rlitly sheared. Jfost of the other rocks show very little evideiio- of shearing, either in the basic or in the acid tyjies. The dilTereiil varieties of ultrabasic I'ocks seem to frradc into one aiioiher. and are usually '|iiite massive. They have in places, however, been jointed ;iiid faulted, and in this respeci they contrast with the ap'.ilc dikes which cut them and which have not ex])erieiiced the same f.iuil inji'. Considering: the (|uestioii of aire from the cutting: of one dike by aliotiii'i'. it was observed that the basic honiblende jrranite, wliicli was sliy:litly schislove or trneissic. was cut by dikes of porphyritic liorii- bli'iide-syeiilte with firanitie facies, a rock markedly more ba>;ic than that ihrcuiirh which it cut, but not at all schistose. IJotli of these dike roi ks are in turn cut by small dikes of orilinary aplitts and of ,iriaiiili<- aplite. Thus in this |),irt iciilar case the relative aj,'o of the three dikes which intersect oiie another is basic hornblende- frraiiiJe, hoinlilciiilc-.syenite, and aplile. The iiciieral rule on i'"orty- mile Cii'ck, however, is that when two dikes intersect the mori' a<'iil one is sliown to be the yoiinirer. In every case where ajtlite dikes were observed they cut ail others. In one case an exl reniely acid ajilite, consisting; essentially of small plieiioerysts of feldspar in t\ };i'ou lid mass ol' liiie-ejrained i|iiart/, 's found cutliiij; a. rock consist iiif^f aliiKisl entirely ol' hornlileinle with much pyrrhotile ami other iiieial- lic minerals. The (|uart/. veins into \\lii<'li the aplite dikes often chanv^e also cut the schists and dike rocks without disturbance, and show themselves likewise to be anion;; the yoiiii;;est rocks in the formal ion. The order of intrusion of l liese dike rocks seems, then, to be ill };eii- eral: I''irst,a series of dioritic dikes with i;ranitic facies; second, h series of more basic diki s, I mi still of the urranitc and diorite families; next, a scries of still nnu-c basic dikes, which sometimes reach tlio extrcii f basicity, as exhibited in tli" hornblemlites and pyroxen- iles; and, linally. an abundant .series of \ery aciil dikes, belon^dn^; chielly to llu' apliti' j;roiii> and inerj;iny: into (iiiait/, \cin8. i:V n- I niKF. ROCKS. REl ATIVE ABirNI>VN( K uf IillKKUKNT 1>1KK HOCKS. 235 Altliou^li iiPiirlyall tlio dike ntckn (l('s<'i-ilti'(l occm- altiiiKlanlly, tlm types wliicli arc intornicdiatc in <-li)M)ii<-al cimiiMisilinii m'cui Id foi'iii tlio laru;('st masses. Next in rclalivcalMiiiiljiiH'i' coinf llic a<'iii iiuarl/- feldspar rocks, wiiicii (leciir in iiiinieiise (jike^; and. linally, llie nidre Imsio rocks, whicli, wliile still vei'v alinndant. are appaienlly smiie- whal less in amount tlian eitliei- the aeid or the inieiiiiedlale irroiips. iHKi"..s oi.' Diia II ci:i:i:k insriiii t. The l)(>d-i'oek in the liireh Creek niiniiii; district is almost entirely ai'the rpjiei- Canyon twn dikes cnttiiiirthe rocks of the Uamp; rl series were noted. .\ltlioui;h t lies iir only a short distance ;\p; rt, they lieloll;;' to e\;ictly opposite t\pes. .\jilili .- Ill I he w ills of t he creek was found a n.iriow ilike of i;ray- isli-meeii, medium- iiaiiied rock with occasional simill pheiiocrysls of feldspar. I'llder 1 lie microscope the rock is seen to con -.i si essentially of feldspar (cjiiclv orthoelase) and ipiart/, w it h a lariic ainonni of epiiiote; some pyiteisalso present, and calcite in secondary \eins. Kpidole is ill lar;.'!' crystalline masses with perfect clcaxaire, and also in smaller crysia line ^rraiiis. Miiii-liiiiiiintjiliiiri . Ill a small ;riill.\ whi( KS. •-';5; 'I'liis I'ock Wits (Mmsidcrab'y tiltcicil, uikI imhIci- the inicroscdiK' ilio i)lH'ii<"'rvsts wci'c seen lo lie mailc up cnliii'ly >i\' xcomliirv ilii-diiiiiii- sitioii iii'odiicts. Tlii'sc idicmicrvsls ai'<'M'i in ,1 uriiiiinliii.iss in wliicli tliore ail' iuaii\ frt'sh liiuiitc cfysliils, wliicli ai'i' in luin miiimiiiicIimI hv 11 trroiiiKlinaj^s w liii'li \ ai-ics ri-mn faintly inicriicryslallinr In aplia- iiilic. 'riicrc is siiiiii' (|iiail/.. wliicii may he drrivi'il licun allcralidii III' llic ariiuriiliiiass. and laui'li calrili' wliicli aiiparcnl !> has a siniiiai' ofiiria: niajrndilc in ciyslallini' I'lirni is also |in>i'nl. lill.All-'N 111' DIKKS Ti> S( Ml--Tii'~n V. 'I'lic riM'ks tlirmijrli wlucli Imlli apliii' ; . iainpiopliyri> cnl. Mlllmnuli not I'Mlii'ciy alloi't'd, lia\ (• undi'i'iiniii' in /niirsa Im-al sliraiini;. Knlii llic dikes nicntiiincd snMii In lii' laid' llian llic di'Vi'lnpMirnl nf lliis slii'ai'iiiir, as is ('Specially well sliuwn in llie ease of llie niiea-l.iinpio- pliyre, wliieli ents acrnss a /one ot' i;ieal slieaiiny' neai'l\ at riiilil annles. ImiI shows an s<'hisliisil\-. In the sheai- Z(ine, near !li niael W ilh llie dike, there ha\e been develdped \ eins (iT w llite i|llarl/ and Ills III' pyrile. It seems plausible I hat deposit inn nl' lliese iiiipre;;liat |i xeiiop'nous iiiinerals may lia\e been the dike into the pleexislillU shear /.o -1 iniiilated li\ the inl riisioii oL ;*•'«( DIKK.S UN Till-; V1K<1N i'.isi.nW i'l i|;T V M I l.K ( i;i;i:K. Ill the sedimeiilar\- series alonji- the \ iikoii imiiiedialely below the lliollth of [•'olt\ mile (reek thi'l'e are oeeaslolial acid ilike: ( Ine III tl lese eollei •led near the moulh of Coal (reek is \ ei\ li-hl -.i;ray in eolor and line-.-rained. with -mall pheiioeiysts. It is a poipuyry of exactly (he saiiii' l\pe a> is round in \arions parts of the ciinnlr>. and is iiliiiosi identical with dikes round cuttinii' the Coast l\'.ini;<' manile in the vieiiiily of llie Chilkool I'ass. I'ndei- Ihe microscope there iire \sls of biolile and feldspar, cliielly orti iase. in a seen small plieiioci linc-irraincd irrouiidina- I i|Uart/.. orllioelase and iiniscoN lie, w 11 h «()iiie i>la.i.;ioclas and biolile. The microLirapliic structure is frei|Ucii ItlKI'.S IN Till'. l.ciWI'.l; ItAMI'.MM's. In the Lower Kampaits from sional dike roe were louild. coiini or ipiait/.-diori Ic. l-"roni the -clii-l- of Ihi I'orl Hamlin to the 'raiiana occa- .tin;;' chielly of schistose j;raliite I nrcll ( reck series on Ihe \'ukon, aboil ■*!• I la miles alio\i' the moulh ol llii w as taken •n of liiie-jiraiiie.l Lrra.N rock uith radiating bundles of f,'reeuish- lilack, libroiis liornlileu le. Indci' t^ic mieroscope Ihe rock was seen 1) ('(Uisist essentially of i|uart/. ami actino ile, wit h some teliNpar am biolile anil small (|uautities o f I'hlorile and liiuiiat ite. The virucinie Is profoundly scliislose iiK'hisiii^' rocks it is probably a dike, am but from the relation of this rock to the d inav liavi' been oriiiinally a ([Uail/.-llorilblende-dlorile, or a horiiblciiiI.-,i:raiiile % 2.'58 GEOLOGY OF THE YUKON GOLD DISTKICT, ALASKA. (^)iirili'. — Alioiit. •'!•") miles below Mynook ("reek dii (lio \'uki)ii there oecui's a liiie-jrraiiied, vefv slif^lilly seliislose roek, which UlKJel' I lie iiiieidseope appeals In he a typical miles below .Mynook Creek eoine in jrreal masses of li,i,dit-f.'r'ay massive i;raiiite, which are iiitrii- si\e ill the older rocks, ;is Iheir contact |ilielioiiiena show. Two eliief dikes were noled, one of which was se\-erai miles in width. 'I'his ;rraiiite vai'ies from rather line-jiraineil to very coarse ami iKirjiliyritie with lari;e pliciiocryslsof feldspar. It is succeeded farther down llie \'iikon by the liiccii dial>ases id' t he Uampart series, and it is there- I'oic |)riibable thai I he ilikes are iiitrilde(l into this series. TIk* undaiit1y, in tlie roeks of liie Haniiiarf seri<'S. On Napoleon Creek the eonj;loMierate which overlies liie Hamiiai'l series and the i'' lii'eii ciirrelaled with llie .Mission (reck sei'ics. On the olher hand, aci 1 dikes anioni; which por|)liyry has '11 idciit ilicd arc found eultint; the SCI in iinienlai'N' sandstones and shales on the \ iikon hclow l''oi'ly- ^o liccn ciirri'lali'd ilel'reek; these sandstones and shales lia\i ilii the .Mission Creek series. seems to show cither that 1 lu' .scdimeiilary beds in the t wo local it ics arc not lo lie si liclly eoi'rclated or thai the dikes hclow l'"iirlyiiiilc Creek iicliuiij; lo a yoiiiiLrcr imrii- jsion. It is likely that the former is llic case, lor alllioiii;li lie- Inoad correlation of the heils in bolli loealilics maybe coriccl. yd those below Fortyinile Creek may bcloiiir lo an older and lliose of Napoleon C'l'eek to a younf^er portion of the scries. In the rocks of the Kcliai (Koeeiie) .series no dikes were obM'i'M'd. It has a I really been stated thai I he earliest frianil ic and diorilic dikes were inll'udcil ]Hi'violls to the chief ili'\clopnii'nl "f sclii>Iiisily. 'I'lie sheariiijr took jilacc after the deposition of the i'oi'iyiiiile series, ami chielly l)el'ore the forinali f the Uainparl series, since the latter series is only sliudilly and locally sheared, much less so than many of tliesc earlier dikes, which therefore wei'c proliably iiilrndcd. in pari at least. Iii'forc the formalion of the IJaniparl series. Il has been sliown thai on l'"orlymil Creek there is exiilellce thai dik intrnilcd at all periods between the youimcsl and the oldest, so thai liiere is a fiiadalion in point of aire, as i ndicated bv relative mclamorphisni as bv trradal ions in si ind iirc and cnmpo^ilioii A\'e may say, therefore, that in this rciiioii there is a scries of dikes the lirst of whiuh were intruded previous to the deposition of llic rocks of llie Uainparl series (pre-Silurian ?) and others at intervals iii) to ir into the pern )l the dcposi linn of the .Mission Creek scries (Crelaccons?). and that llii- rocks and ended with more ai series beu'an Willi uraiiitii; or dioriin.' d and more basic rocks. #i: VOLCANIC OK lil'KUSIVE ROCKS. I'.MJCDZon— liAMI'.MtT SKKIKS ( DIA 1! ASKS). iii;M;i: \i. ih.m kiciiun. At a hiirher iiori/.on than the T'oriyniile series, and probably liich are larirch of volcanic orij;iii. (' rocUs w directly overlyiiej; it, ai 'riiroiiirlioul thisscrics there are irrcil ipi.-ml dies of diaba.se, ^^enerally t L'K» (ir.ol.fKiY IH- TIIK YUKON (!«)M) IHSTKH'T, ALASKA. cdivitic-hfiiiiiiK. wliii'li varies Iml lililc in sliiicliin' iinil appraraiu'O ill wic|cl\ si'pai'aii i(>cks ail' Iiil1'a< ii?< sciliiiH'iils wlii( i| liM'aiilit's. Clii-i'lv assiicialc(l with llic cryslaliiiio ii arc (lcii\rci ciilirclv fniiii iIk^ dialias.'. and wliicli lonn a very laiyv and imiioilanl pari ol'l lie scries. Tiicsc tiills irradc into impure saiidslipiies. sliali's, and liniesloiies, which arc nlicii ^daiicoiiil ic. I'rniii the y:iauc()iiite in tlic lull's and jiloi'ilc, and citiicr ininerals I'l-oiii the deciiiiipiisil i(pii silioii proiliict of the aujritc, and the ealeilc, epidole, and ]tyrit(' are also si ndary. An e.xlremely eomiiion dccomposilion product both of olivine and of aii;rile is serpenline, to which is due, nl'I'HR.] VOLCANIC (>l{ KI'ITSIVK KO( KS. n |iiiill.\ ill Icasl, I lie rock's jji'ccii color in the liclil. Tlic i|iiMrt/. i> mhiic- I lilies sccoiiilary and soiiicl inics priinai'v . and occasimiallx iiici lasf. In (|iiaiilit,v so as 1o form an essential I'oiistit iicni. In -.iiiiie ci-m'^ the aiiiril<' is entirely a Itei'ed til t^rei'ii liorn blende, and I lieie results a linrn- l)leiidi'-|ila;,doelase rock, which niiiilit lie styled epidiirite. Itse\ident derivation from the typical dialiase, however, it^ Held relatinn-.. and its occasional and reslrielcd occurrences seem to make such distinc' live Jiaincs as t his .siiperlliious and inisleadiiiu;, and it is hesi. I lieie- I'ore. lo consider all 1 liese rocks as phases nf a typical oli\ iiie-dialiase. In consideration of liieir enormous luilk and extent, the dilTercnecs are remarkably sli^dil. .Mlhoimii even thi' rniest-j.''raiiii'd i;;neons rocks, which are aplia- nit ic ill I he held, show . so far as oliserved. a holoerystalline si met lire under the iiiicros<'ope, yet in till' tnlVs. which are coiiipiised iif the same material, fray:ineiils of these line-^'rained holoerysialliiie rocks urade into others which in places show a irronndmass uf cry|ilocrys- tallinc ornoarl.v ^^lassy st riicl iirc, and t his i;romidiiiass contains small pheiioerysts of the essential minerals which make up the dialiase. Ohviolisly these are to he <'lassed as basalts rather than diabases, and yet the.\' evidently represent only a slight textiiral and structural ehanj;o from the liiie-i;raincil holiieryslalliiic rock. Specimens of this altered l)asalt wi're not found in place, but it is probable that they tints iir. NoMi'.Mi.Arrm:. The si met lire and composition of the <'oarser types of the iijiieoiis rocks of the Hampart series, as well as their appearance in the liidd, are those of a typical oliviiic-diariase; yet these rocks ;;rade into liner phases, wliicli (ire aphanilic in the hand specimen, and pnibalilv into rocks with cryiitocrystallinc ground mass. .Ml of these are midonbt- eilly surface Hows. The 'rcrtiary basaltsof this same rcjiioii areofieii fine-grained ami ain.vfiilaloidal, and also often holoerystalline and ophitic, and in slrnctnre ami composition arc sometimes exactly like the rocks of the Rampart series, the dilTereiice beintr that in the older rocks the feldspar, auirite. olivine, anil other coiistit ueiils are more the Terliarv roidis are nearly l)laek. iJoih, however, are esseni iaily holoerx sialline pla- f,noi'lase-ailiiite-oli\ iiic rocks, with cryptocrystalliiie or glass> phases, and both are surface Hows. ( )ri),nnall,\', therefore, they seem to have been the same, 'i'liis intimate relal ioiiship is not expressed by the terms diabase and basalt, and. as a eomiiromise between existiiifi nomenclature and the actual facts of relationship, the terms basaltic diabase for the Uampart series rocks and diabasic basalt for tiie coarser poi't ions of the 'i'ertiary lavas are |>roposed. It is coming to be reeogni/ed that the old terms of ])etrography are incapable of expressing the true relationsliipof rocks, and n> more accurate system J.H (;koi>, I'T .'{ Iti w •_*42 (ir.oLixiv 111" Tin: yruoN c.oiA) imsti;k;t, ai.aska. has ,vi't licrti iulc.plf'l: hut llif li I'm' si'pi'ialiiiy: nirks as In tlioir afic and Miijiin by pcciiliaiilics dI' Mriictiiiv and coiiiiinsilioii hasKimi" 1(V. In an i^rncoiis mass dillVicnccs in crv slalli/atinn alone will irivc list' Id varifiirs wliirii nnflercxislinj,' rules of elasMiliealion will Iteiiiiig let ijiiiii' cjill'erenl irroups. TI'.IITI \l;^ li ASAI.TS. Ai various points aloiit: liii' Viikoii and its ii-ilmtnries afe (lows of basalt belonjriiiK ( i.r.\vi>. Oiitlio Lewes, for |i> miles below I lie Jnnel ion willi llie j'elly, llio rif^lil bank is a perpeiidieidar clilT of vesienlar brie basall, wliieli forms i)ail ofa eompaiaii\cl\ level |plali'aii. risint:-on , .;im) feet abovn the river. 'I'liis la\a Mow lias been noticed by !>awson, Uussell, and Haves. |)r. Hayes ' ascribes it to two or more vents in llie immediati' viciiiitv. These \cnts are siipposeil to be markccl by lii;;li liills, one- about III miles ami the other 1 miles from l''ort Selkirk. One of these hills is a synimel ileal cone, find is said to have on its smiiiiiit a small lake, which probably occupies the crater. Accoriliu^r to \)\\ Daw- Mon.'Mhislava field i.sc()iii|)osed of several superposed flows. Iiifortu- nately no speeiiiieu of the rock was collected, so that no iletailed dest'iiption of its nature can be i,dvcii ; but it is undoubtedly the same as the basall at .Miles ('aii.\-on ami the other flows which will be described, MII.F.S ( ANYUN. Orriirtriirr. — The rivei' eonnectinu- Lake .Marsh aud T,ake TiObargo, which is that portion of the Lewes called Seventyinile Ki\'er. cuts throujrli a How of basalt about midway lietwcen the two lakes. In this llowihe river has cut a jrorure about I(mi feet wide ;iiid half a mile lonu:, with JM ipemlicular basalt walls from tin to si • feet hi^di. This is known as Miles ( aiiyon. Thiduirh this narrow cleft tiie whole vol- ume of the river is forced, producini'; a torrent of excessive turblilouee and rapidity, the water lieinj; arched up in the <'enter considerably hiiilier than it is at the sides. .Midwa.\- between the two ends of the canyon is a steep, circular basin, where the water eildies around rap- idly before pluni.'insili;;, ilixl ill tilt" cud is a iiaiiow uii|-;ri\ saiil In I lily :.'i) nr :iu Iccl, \»ii|c. wliicli can lie .seen only at cxi rciiic>l\ li.w walcr. I'l'mn ijic iicail I'l' the caii.\i'n Id iIic I'lml of llic W liilc l|iirsi> tin' di-iaiH'c. as iiicaMiicd by Mr, <»i;il\lc,i i> j,- miles. 'I'lic basalt at this locality is .said not in extend l.-ir alio\ <• ..r lielow llii' |ioinls iMcnlioiied. I' is made up of se\enil sii ssi\e shcits, w liiidi sihiw licaulil'iil iMilmimar si met live. It is soinei imes mas>i\ e, MOllK'tiinCH C.Mlemely scoliai'iolls or lileliliy. At llle W liite llorsi) Ha] lids si rat died sills and ;;ra\ els lie on to)! oT I lie lia-~.ill at ,i liei:;lit of Jll j'ccl. or mole alio\ e I lie lU'esent I'ivcr. SIriirhiri iiiitl 'ihiiihiniIkiii.-- .\ s|)eeiiiieii of dark-lnow n \esniilar rill. I."i. lill-alt, w la\ji from tlic canyon is seen under t lie iiiicroscopc to eoiisisi eliiilly ol" i)la};ioc]as('-f«'l(ls|)jir and olivine, Tlic feldspar is in narrow strips with rajrjrcd cdircs and liordcrs. and the olivine in crystals which often show rouylily iie\ai.'oiial outline, disseminated Ihidiitrhoiit, so - t imes in cloudy masses and a.iraiii in liliers or shreds, is an aliiindaiiee of rcddislidirown material, which, iinlced. i.'i\ es color to the seciion and prolialily to the I'lxd. . This, from itsoccasioii.il association uilli olivine, is prohalily Hci'penline stained with hematite and otiiei nu'tallic o.xidcs. <^)uartz is iiresent in siii.ill amoiinl. .V s| iiiicn of lilack crvstallinc basalt, with oiih occasional \er\ small vcsitdes. 1ms 'Ann. Ui'jit (-(•■nl. Nut, Uist, Sui-v.v Ciinacla. V..1 III. I'lii-I 1. j. MH :lt'- f*5' ii i .'i- ■J I I i,r.nl,(i(i1 (IK TIIK VrKON (iOMi DISIRKT, ALASKA. (•SM'llli:ill\ lllf silllir i'li,(liirlt'rislir> Jl-^ Illill ,|llsl (IcM'lillcil, cvci-pt lliat III!' (•iy.|;il> lire ImiriT mimI ;ni ii|iliil i<' >l iilcl lll'i' iscillcli well showil. Il also t'liiiliiiiis I'Diisicli'ialili' liliiiiili- .'iikI lji:iu:ii<'til('. Cirii KI'N AMI SM'iil.KiiN ( lirP.K^. iilci()|» liclow I lie main tmks. a|i|iaiciil l.\ overlying' shales and slialy (Mial scams, w liidi have liccn icrcnc(l lo the Mission < 'icck scries. It is ncaily lilack and limly liolociyslallinc in I he hand specimen, and 1 1 111 I c njassix ('. li is said to oiilddii in places (i\ ci I h" w hole conn i ly ( I rained liy tlie lower part of I he creek and its 1 rilintaries, and on .Myers l-'ork to I'orm the walls of a canyon I ("i feet in deptli. (In Napoleon ('reek,.inst lielow t1n> nniin forks, is fonnd dark-hliie, nearly hiaek basalt associated witli arenaceous limestones and ifi'its. which likewise ha\ e liceii referred to the .\|ission (feck series. In the \ icinity of t he basalt t lie limestone is nuirnKH'ized and apparently somew hat dolomi/ed. In the upper part of P'raiikliii (iulch Ini'fre Ixiwlders of finely crys- tallinc basalt nr in the ^Travels, where they are known as "'jfold rock" by the miners, sinc(> their considerable siieeilic ;iravity tends to iiniko them sink to the bottom of the j^ravcls, where the ji<'l'l •■dso aceiimidates. Sfriicliin (i)iil (■(iiniinsiliitii. — .Speciniens e(>llect('(l from Chicken Creek, Napoleon Creek, and Franklin (Jnlcli are all identical in appearance, St riM't lire, and composition. I'lidor the niicrosco])0 the rock appears to be rather coarse-^'raiiie(l holocrystalliiie. iind consi.sts essentially of plau'ioclase, angite, and olivine. The pla^doclase is in fresh, latli-sha|)e(l crystals, which have the ophitic arranjiemcnl ; the aiij^ito is often considerably deconiiiosed, and in places has appar- eiiMy ,viidde(l brown heniatitt* and nia^fiietito, and the olivine is some- what allere(l aloii^ the mai'j;iiis and alonj; ci'acks to ureenisli-yellow ser[)entiiie. K'lVI KlK MdlNTMN .\NI> liri.uW. A I' K'U I h( K Mnl N IAIN. o, 'cfiirn iici mil. hi. I SI' ri III mil -Oil the ^'llkon. .just below llie jinif lion of the Koyiikiik, a perpendicular clitV rises directly from the water to a heiuhl of jirobalily "tm or SOd feel. This is known as Koy- iikiik Mountain, and is compose(l of basalt. On its smooth and nake(l face two systems of colnmnar joinlin;,' are dexi'loped with diaf,'rain- matic perfection. One set of .joints is nearly vertical, wliile another. rlv Ir iontal, is at ri}j;ht anu;les to the lirst. The hori/.ontal joints are closer to}jotli(>r than the others, so that while the lirst set represents the ordinary colli in liar .joint iiiji; of lava Hows, the second is like that oft "11 found in dikes. It is e\ ideiit that the hori/ontal joints were formed subsc(|ueiit to tho \(,'rt ical ones, t ho lirst conlraction in ri (•ri nil 1 voi.rwic iiK Ki 1 i'si\ i; kim ks. 2 »-> fx 111!' I'liiilili;; l;i\ll lui\ill^ li;illll;ill\ | ii'i ii 1 1 jcri | iTi|i-U> i ir jii||it>. rii||o\\. in;: llii' iliiiTiinii III' li'a>l n'>i.siiii , wliirli «,is |MT|i.iiiliriiliii' tn ilic llppi'i' mill liivM'f I'jiri'^ III' ll Milium: -IhmM. whili-iiii riirllii-r I'lmi r.u'- limi llic ilil'i'i'tinll III' li'iisl ii'vi-l.illrr I ;iirii' |ii'i |ii'iiil ini la i In llif joint cfiH'ks ali'iNiily riuiiii'il. ami lliiis liDfi/iinlal .i«iiiil>, rluM-U >i.t lii^rfllicr ami iiimiliii; rnmi uiii' viMiiral Joint to anolliir. \mto ilfvi-l- opcd. A ronuli iliai.'ianiiiial ir >ki'li'li is ;;i\i'n ( li^'. hO. Inn mi tlif rlii) ilxi'irtlif joinls ail' >liii\Mi iiMii'li Mini.' jiiainlN. iiiiil'oiiiily, ami hi^aii- liriilly than ran lir sln.wii in tin. iljav.iiini. ami for rarli Joinl in ||||. iliairi'ani I licri' an' a liiMnlri'd in tlmi'lilV ilsi-lf. 'i'lir imk Ci inning; I his clilV is ol'irn ilark-lilno or f;ray. niassix f. ami tinrlv liMloriv-iailiiii'. In otiiiT plari's it is poiphyi-itir or aniy;.'(laloiihil. Im-luili'il in ii aio lary:r ri'jiuiiii'nls of allnrfij siMlinii-nls, such as i'ony:loini'i'alt's ami sandstoi, s, uliiili liavr Ihtii lianlcni'il ami rcilili-niMl hy ihr liakiii;; to wliii'li Ihi'y liaxf lirm sultjiTlfil. 'I'Im' la\a \M'atliir> alonir Joint jilancs in places with uicat ra- pidity, pnidncin^r ronipari riays of various colors. In one scam noted the central ]>art. adjacent to ilic Joint, was a delicale hlne- ;^i'ay in color, ami was ijuilc piil- venilelit. On lioth sides III' I liis were ;;icaler ihieknesscs of yel- low, oran;:c, and linally li^lil- red clay, chan;;inf; to eil .as paints l>y the Indians and are consideralily iiri/.cd, lieinu' carried lon^' dis- laiices for tlie pni'pose of Iradiii^' to other Indians, 'i In- enlirely decomposed and leached liliie-fii'ay clay, mixed with waler. was used as a paini or whilewash for the inierior of ai'aliin at Niilaio. whert' oiir parly slopped. This cabin lielonij:ed to a while I rader. SI mil II ri mill i-niiiiKixiliini. — The only specimen of the Koytikiik Moiinlain laxa which has lieen examined iiiicrosco,iically is. nnforlii- nately, decomposed. .Mey:asco|iicall.\' it is dark-i^rcen and aiiiy;:da- loidal, the am,\j;iliiles beiii;: partly i|iiarl/. and ejilcilc Inder tlio microscope a larp: vosiclc, whose walls are lined witli serpentine, is tilled with harite in interlockinj,' plates. Manysniidl ovoidal vesicles are lined w ith .serpentine and (i lied with chlorite. There are comjiar- atively lai'tfe |>heiiocrysis. which are now psemloinorphed liy calcite M /il-ll I : ■ h J't- I 24ll liDdl.oi.V i>|- Tin: MKdN i;tiiicl iii-e of tin- u^■'lllll'llllfls^ i* a> if iiiiyiii,ill\ ciiiiiihim'i! ">f lii>liM'rv''tailiiif pJH- •.'iiM'iji'><' .Mill .tin.'!'"'. 'I'Ik- .iiiiri'*' i- .•ilniijiliiiil jiiiii iiiii i;rciilly ili'ciiiii- |«iM'i|, liiii till' iil.iL'ii'i'lasi- *tiil-« hiixr lii'fii i'i>|i!,'t<-i i| Ity pst'iiilo- iii..r|ilis ..1' villi' 111 111 r mil. fiiil. "Iiiili !■• aiii a'-'iill> . in pari ai li-ast, i^.iiiiipi. Till' im-k l-> i'\ iiii'.ii l.\ a ii'iU' iiliviiii' l(a>>all I'lHisiurralily alii'i'i'il aiiil ili'-'iiiiipiiM'il. Till' si-iiiiii iiiai'> lii'ils v liii'li ai'i' ii.i'Inili'il ill iln' KiiN iikiik Miiiiii- taili ha.sall at''' I'Vpii^i'il a i-'li'irl ili^laili'i' Ih'Iiav iIh' iiniuiiiaiii in: iii- pai'i.ii\ I'll utii!i'«\ iiilii'il •■iinililiun. 'I'hry rnnsisl rlii :iy uf iilark -liali'^ ainl lini\Mi-\vi'aihi'i'in;r samlMlniii's. ami arr ri'lViTi'il liy i'M. jtali 1(1 till niaiiiii' Mini'i'iii'. 'I'liry liaxi' aln-aily Ih'i-ii ili'M'iJIii'd mull r 111! Iii'ail nl Niilal'i sainKluiii's. I''.\ 'i\ wlirii' hi'iv.'i'n tlic Kiiyiikiik Miiiinlain ami lln' ili'lla of III" N'likiiii aii' Ti-i-tiaiy saml- -inlii's. .sliali'>. ami I'liiiulnnii'iati's. fii'i|ni'iitly niin^xli-il «illi basallii' I' -I- -. « liirli iifii'ii ^liii" li'aiilifiil I'lihiinnai- >trm'lmi'. Ai An\ik is !ia>ali iiki' llial nl llir Kii.\ ilkilk .Mniintaiii. ami lii-ii' also tin- ili'i-uni- |iiisi'i| /.^•nl"^ fiiriii'
  • in- I'lali'. wliii'li nia\ pussilily In- a Im-al ii\ it fui'iiialiun. AI llnlyl'i'i'ss Missiiiii >pi'i'imi'ii^ iif i'iiii:;|iiiui'ialr>. samls'iini'. ami l(a>,ili wni' ccil- li'i'l.'il. ;>i'l((« An.i/i'af'.k' llii'i-f aii' iid siiliil rucks, i«;'l mily llic Hal ilcila ilcpiisits, aihl iliis I'liiilinncs in he llic case iiiilil SI. .Mii'liacl Is I'l'aclicil i''riim ll,. liM-r, Iiuwi'MI-. a line of liilN. p' ilial>!.\' lia'-allic, liia\ be Mill iiiiiiii _: I'liiii iiiiiuiislv liiini Amlrealski In M .Nlieliaei, ■-1 . Mil IIMI. l~l..\Mi. (h'lirn iifi' iiiir! I/I III I'lil ili'firiiihuii. — Si. Michael Islaml isaimnl 7") mil' .• nnrllicast nf tlie .\ pin ion, or nnriln'miiinsl imini li uf I lie \'iikiiii. < Ml ii •iinateil tile I'liief Iraiiinu' pusi nf the Alaskan ( Dniiiiei'cial 'iiNpaii> ml tlie Xuiili .\nii'ii'an 'I'l ail lie.: ami 'rranspni'ialinn Coni- p.inv . ail', it .^ I lieli'liil'c llie piiilll .'ll «liicli iieeail ■"leailiel'S are linliiaileil anil river sleailieis l.iaileil villi sllp|ilies for llle coniilry lip lln ^ iiknii. Xear it is aiiut iier islaml of .'liiiiiil the same si/e. calleil Mewail Nlaml. Michael Islam! ilsell i'. alimil s ,,v '.i mil u iili li. all lniiii.;h I 111 he son I liwesl a Inn;' lonLrn*' .-' ii'ichcs oiii. makinir in this ilireelinn l-"ior pi luiles. The whole of M. Ill' total li'ii:r>li .Michael anil m'i;;hliiirin;.' is!aiii|s ami of the ail.joinini: inainlaml appears 111 he pnrclv volcanic. Near the I railiiiu: post the chief la\a 111!" w hii'li i- nil \ isihli. is a I loll I . 1 III >f I he sea at liiL'li tiilo, W here wasiieil cliaii h\ the water it is w rinkleil or ropy, show in_' it. to lie the line upper snifai f a lava llnvv. These vvriiiklinL,'s .'ire en rv I'll, imlieat in;; t lie ill reel imi of Iln.v . I ml the ili reel Inn < liiii show n varies from place to plac.-, as it Irom eihlv inir cnrrcnls. .\liov e I Ins ! I I V III \OI.( \M(' a lii'il 111 \»iilill;iii| 111,1 Ifliii I, ell it'll \ i\l i i|iii|\ •m-.i|i,ic'i .ii|s hiva. iii'iirl.v |iiiinii-c. Inn aN.i |i,iiil\ .iml in -.>i m^i-^ l.iri^ch dax . \ iilcaiili' t>lii'll lull nl' laiLri' |i, aiiii'ii|,'ii' a- in ]■!■ iii'ailx i'iii|iU il" .■ninparat i\ '■!>■ I'l'i'-li; llii* |Miiliipn. 1im\\i'\ i-i-, i> nii.ii i|<'c'i>iii|mi'm'i| i.. u snl'l. fell oi- liiav . Lilil l> ''lav. ici'aliilii: I Im' i1i'i'l>inal Imw Mi't'. .il saiicl> i i" ami -lial'-. iiiiisih iPliirulai'. all"! cil'ii'M a Inni iw inori' in rliaiin'li'i . lln'\ arc uliip« n>p i-v i a li<'i;:lil nl' I'l'ipiii I'l lip .'n iVii . ami alupM' II cipiiu's a Miliil >lii'<'l ipI' I'M rt'iiii'lv -.I'Mriai'i'iiii- lava "i in - lii'I lliirk; llii' tipji i< lii'ailx iiiiiiMi'i' 1 I'lPMii's aiiaiii a i'la\> ' "ali'ilaH i-|iiiMl. iiia III' lava, ami llii-> li.Mr, wliiili w licl'i' ipIi-^civ 111 1^ I ur ."p I'l'i'l I liii'k. i'ip|i>l il Mil "< iii'ai' till' |ili. ('nilirs.- Al "lilTi'i'i'iil ipuinl'Mpn lln i-laml i,iic' rinii'iir IiM' iinimiii \\ li;i'li ari' n iih :i I'i'vv |iiin>lri'il li'i'i alpipv i' 1 1 •r.il livil. IpiiI iiipI ircalili III nn .i 'ircal ili-la iiri' liv i Inlri'ipiil ra^l In I hi' m'.iilv |ii'i I'li'l Hal m-ss III' I III' ri'i' . 'I'Ih' imp>i i'ipn>|iii'iiinis ipiir i- a sliarp <'ip|ii' w liirli hi a mis mil fai' rnnn I lir siiaiK lii-l vv.'iip SI. Mii'liarl ami Slew ail I--l;inp|. Tlli-. is |ll!l pIppWII IPII llli'l nasi ^NIV ( liall Nn. V ;;'."i as "»!,.|i||,.||s .Miiiinlain. ami is Uiinvvn in llip' n.ii i v I's ,|s ( Ihiu'I'MU 'I'll" sihimiiiI •_'4>« lil;l>|,..l■^ cii nil; yiindv i.ipi.n iii>ri;iri, m.a^ka nl'tlll-. l-iilllv .iImiIII IlililliM illw.M' llir -.il. ImiI jl iIm-s sill'\<\ i-liiil-1 .i> >l Vlii'liiici Miiiiiiliiiii. IJiilli I lii'M' (•iiiniiini> iiinl I \Mi III lii-i« wliirli «iti' \ isilcij iiii' liihi; I'si iiiiM \ iilciiMiii— (l''ii;.17.l < Mi I ln' lop iil' <'iirli is n circii- liii liii*--iii -uriiiiiiiili'il liv il sti'i'|i iiii'U Will! iiiiil lilli'il wiih iin ii'rf;;iilai' il'M I IllilSS III riiisl-li\ I'll llil« lllcis Till' lilMI 111 lIll'M' IlilW IdlTS is r\ln!iirl> \ I'sji'iiljir. iii'iiiiy |iiiiiiii'i'; il i> liljirk nlnn rii">li iinij ml 111! ii\iiliii lull, iiinl il- siiii'iii'i' i- ul'ii'ii r"|>\ jiihI >liii:i:.\ . TIh' I'luii'i' liiisiii I- 111'-! ■.liiiuMiiii III!' iii|i 111' Si. Mii-liiii-l Miiiiiiiiiiii Mi'|ilii'Ms .Mull nlii ill. 11' Cliiiii'i'Mk. is il l:iii;i' iTiili'f liinki-n i|ii« li iiii"_'liliii'iy. su I hill Mill' 111' I III' CI I IT' 's I 111 'SI '11 Is ;i >liiir|> iii|'.:i'. u liii'li iippciirs lilvi' il I'liiif III il Hull' ilisiiiiii'i'. 'I'ln- pliiiii 1111111 wliii-li llicsi' I'liiiiii'iii-i'- risi' i- I'l'iHii L'l I 111. 'ill I'l'd aliii\ I I III' s.'ii. iiinj il i'>iiiiivil\ iiiiiili' lip. iis >||iix\ II li\ iiiiiiii'iiMis si'c- linlls iilnli- llii' slimi'. Ill' si lill ilii'ij ilsh. vvilll lilM'ls 111' lilii'l- i-laVfV iMiili'i'iiil. Iti'iii-iil II I III' iisli. nil il li'\ I'l \\ il II I hi> si'il. is ill niaiiv |ila<':'S \isillll' il IhmI III' l>ii«|i|i'l' ilil\ ullii'll si |iii|'.;|y slI^^iTcsIs ii'i' iU'liilll. Till' i'\ iili'iii'i' sliiiW'^ iliiii ilii' hiNii siii'iiiii- I'iMili'il lii'iii'iii II ilii' siir- I'jirc 111' llii' -.I'ii. iiinl il is s||iiii;_r|x piiiliiilili' lliiil ihi' Mili'iiiiiii's wiM'i- Mlliliiillinr. rill- iMiMiii- liipML:iiipliv 111' Ilii- isljiiiil mil liiirdly In- <'\pliiilH"l I'M'i'pl li\ llii' iii'liiiri 111' iiiiiriiii' I'lii ii'iils, iiiiil I'M'ii llii' riii- ti'i- iM'iirllii' iiiiirks 111' iiiiir Ml' iiiisiun IIh' I'lniiii'iii'i's imu shmvii an- iilil.N llii'lipsni v iiii'iiiiiM's. ihr ri's' liiiviiii; 1 i \i'iiil up liy XMili'i'laiii ii>>li. SIriiftilii ■mil ruin jin.silitill i.''/i'i'i/.- .\ spi'i'i im n iil' |li'>|| liiVii I'i'iilll till' lnwi'sl Ijiiw nil llii' iinilli >ii|i' iil llii' Islallil is (link lifiiv III I'lilm-, Willi i,M-i't'iiisli liiiinls. iiiiil is liiH'ly puniiis. I'liilcr llii' iiiii'iusi'iipi'. lIllTC Jllc sri'll |llil|l\ pln'lllll'|-\ !.ls III' I'l'i'sll iili\ilH', "CIH'lillK Willi pHHJ fiysliilliiir I'liiii rii.'si ill!' iiH'lii-i'il III il liu|i)cr\ siiilliiH' iiiasM 111' pljiL'iiii'lasi' iiiiil iiiiiiili'. Iiiillilii \ir\ lii'sli I'liinlil lull. Tlii pja^fin- cliisi' is III lill II shiipcd i'i'\siiiK, iiinl ilii' iiiiirii,. ill iiiipi'i ii'i'i iTNslals nr ii'1'i'L.'iiliii' ;;riiiiis. 'I'Ih' pliiy;iiic'liisi' liiilis ui'ii'ii liaM' ;i paiiilli'l iii'i'iiiii:<'iii<'iii. sliiiw liii: Ili«> I'lVi'i'is III' liiiw . Ill ii;:iiiii iii'i' \s iiliniii i|i'liiiil<> iil'ii'liliii Hill. 'I'lii- pull's nil' iiii'/iiliir in sliiipi'. iiiii| llicii' is nil ;;liiss niiiiiii.v siiiiiiiliii \ iiiiiii'iiils. \lir.;iii'l 111' ill siiiiill II \ sliils I-. iiliiiniliini, ilftni ilirlii.scil ill lllc iilivillr plii'lliii'l'\ sis I'l llii I IIM l(l\ 1 11. .Mr. I{. ihi' niniii h nl' iln Kapiil l{i\fr. iiiiil is Jl iliick slici'l iivci'lyliijf sliali-s, i|iiai-l/.ili's. 1111111111111'. anil iiliicsdiiics. Tliis li.-isiili slniws 111) |i\ iili'iil I'liliiiiiiiiiisliiirliut'. Iliiiiit;li IIk^IH' ill'*' rvitU'lH'i'S ol' ttilTfrclll llnw.s, I,, Irxllirt' lIlc im'k iTliHli'.s 1 Ann Hi'pi in'i.l .Nbi lllal siirvi'; innmlii, l>'»» "H. iiji rin l.tlli fp^' 81'1'HH { viii.cAMc OK I.I II st\ i; i;i" K •.'4l> I' ruin iiiiMlcralcly coarsi' aiiil :;iaiiiiliii' In liiu' uiann'il. ami in plai-i-s it l)ci-iiiiif-. \ csiciil II' anil ainv '^"laliiiilal. I'lu' -.|H'i'iiMi'ii» i-i>11i'i-i.m| wimi- (■iiin|M»i'il |ii'iiii-i|iall,\ III' ailixiti' ami <>||\ini'. nnIiIi snini' iiiai:ni'lili' ainl I ilaliilViiins iiKii. ami wi'if aliiioNi i|i'v|imiIi. n\ |Mai.'inila»<- \i'ai llii' <'ml 111' III!' IJaniliarl-- lia^all ts a;,Mili Iniiml ■■Miiyiii;; >liali-. slalr-^, ami liini'-lniii'-. " Ml 11. icn I.I!. III. ( \\ llaM'>' mill'- llial ililiiiii; In- .|iiiii-m'\ almi'^ Mm- Wliili' KiviM- lilai'U \ i'? >iiii al a iiiiniiii-r 111' idcalitii'-- lii'lwi'rii llic ^ iikmi ami llii' Si. l-'.llas Mminlaiii-. ami llii> lava a|i|MMi-- In rnnii lnuail iiir^a- iiuilli uf llic ii|i|m'|- pail 1)1 lllr \\ hill' l.'ivci-. I'l I i.s iiiv I If. Di. li M I >aN\^iiii ' mili'^ lliai .'il i In' iiiiiiil li ul' II>hi!i' Itn ii mi i la- I'i'lly ail' liliilT> 111' ilai'k-liiii« II lia'>all. uflcii aiii>;;ilaliiiilal m- M'^h-ii lai , ami luiilaiiiiii;.' rliali'i'ilmiN , I'aliili'. ami /imiIIIc, Inn scarci-lv al all ('iililiniiar. I'*ai'l Iiit smii licasi I lie ■>aiiic i;i'iilii'j:ixl lia> imli'il liaNill^iii llii' SlikiiH' \'all('>. ami Im'UM'iii ri'li"_'ra|ili (ii'i'k ami the 'ralillali |{i\ IT I lii"^!' Iia>all'~ III I "111 iIm 1 I'liaiiin'l- ami hv itIh' aiiriri'iiiii> ;;rav ■ I'Is. Still lai'tlicr Mint li('a>i. near ilii' Miiilliriii pni'tinii i ,' l!i'itl>li ( "ililinliia, arc ullirr lia^all llnus. rnriiiiiiL' a iiniri' or li"-s innmM'ti'il I'liaili ii'ai'liiiiL: 111 ' 111' lia-alN nl' \\'ii-.liiii'.^liMi, i •ri"^Mii. aiii| < alil'uriiia. la'.^i Ml' "I , . iMni-niii.s vsn ~n:i ■ ii iti: "i ii\~m.i III i'\ crv I'aM" « I II' I'l' inici'iix'Dpii' i'\aiiiiiial imi lia-- I ii iiiaili' ul i In' lijl.sall (ami I lli> lia> 1 n ilnin' u il li x|ii'iiiiiiii» I inin \ ai niii^ Imalil ii's I'l'diii .Mill's ( aiiviiii In M. Mii'liai'l. a ilislaiii'i' in a -.1 iai'.:lil liiii' nl' a llnni-aml iiiili"-i lln ,i|ipiarain'i', .-.I nnl iiic ami cnniiiii'-itlnii aii' I'l'iiiarkalily iiiiirnrni In i'mi-n cii'm' iIh' iih'', is an nliv iiii'-lia>all. I'liiiipnM'd cs.M'iil iail> nl playini'laM'. aii;;ili', ami iili\ im-. ilii' >l iiir- Uiri- i> u'l'iH'i'Jill.N liiii'lv Imlni'i's stalliin', ■"iiiiii'l iim"< l> iniiiy: ininlt'r- ali'U inai'M' ami ;ii'aiiillai'. ami >iiim'llinrs ay;aiii scry liiii' u'laiin'il, '»>> llial il i'» iitil al«a.\- i'as\ in ililTi'iiiil iaii' tin' ihiinI ii nciii iniin'ial.H with llii' niii'i'iiM'iipi'. riii> last i> i-.pcciall\ lln' la-i' winri' llii' mi'k is aiiiM-'ilaliiiilal ni M-sii'iilar, as it is apt In In- iicarllit' siiiiai-i' nl' lliiws. Wlii'ii till' la\a is ill this latter I'ninlinnn ii is rs| iall> lialili' In nviilal inn, iiliil llii' I'l iiiiial inii nl si.| pi.|ii nil', limniiiii-, ami ntlii'r • Ifciiiiipiisiiinii pi'iiiliii'ls iilisi'iiri's in snini' il"'i;ri'i lli" m luiiial si rin- Inn-. Ill pliii'i's u lii'i't- till inii'i'iisi'iipii' I'Miiniialiiiii was inaili' iinraiiN sliii'lllll'lls I'ldlfi'lci;. III!' rni'k sriMlls In III' |. li'll* li'a 1 III ajiprall ■ « illi tliDsi' wliirli lia.i' lii'cn siinlii'il. .vnl 111 11 »s M IS. All III'' liasalls uliii'li liaM' In m nliil liavi' mil hiiIn Mn- saiin' strinliiri ami riunpnsil inn. Inii li.ivi' fxpi-rii'in'i'il ali nil tin' sann' Kxi. .-.11111. II ilii-"iii
  • iiiii. Il is (■\i(|riil. llii'icrnic, that lliiiii^li till' (linen-Ill lliiws .III' pruliably imi sliii'llx riiiilciii|ii)rai lis tlii'V wiTi' Hill M'liaiiiliMJ iKpiii iiU Willi till' S iiknii, ihr liasalt lias limki'ii IlifiMi:_'li saml- .stniH s anil sliali-s hI .Minri-iii' ayi', ami i-> tlhTi'iiiri- lali-rtliaii tin-si- s(-iliiiii-iits. (Ill till' iitlii-r liaml. at tin- W liit.- Ilursi- Uapiils tin- lava is i.M'i-laiii li> stralitii-il silt* ami l'ijimIs \ -.limt ilistai I'aitlii-r iliiVMi till- liM-i- thi-si silts ami i;i.i\i-ls ii\i-rlii- -iMir clay nf u'lai-ial iirij;iii. ami lliis aii'l "llirr i-\iili-i s alii'ail.\ i-iti-il ■•linw that lli'-y wi-ii- Ciiiini-cl al'Irr tin- ii-ln-iit ul' tin- '.'laiii-r; ill this i-a.si'. llii-n-l'ui-i-, till- basalt IS iiml limits in iiiiiiil. \M' iiia\ ioiiskIii tin- liasali as a « hull- u> \»- pinlialtly in lai'iiri- jiaft I'liiii-iiii-. I>i'. hawsipii.' liciNN. i-r, nil ai-i-i)iiiii ipf ilii- hh-mliiii.' of tin- Hfitish ( iiliimbia basalts vviih lakt- (it'pnsils « liirli liav Iktii ic-iVn-.-cl 111 till- Mi Ill', bi-lii'\i's tli,:t at li-ast the tirs; i-i-ii|>ti(iiis tcmk plai-i- in this pi-i-iiiil, all 111 111;; Il I In- \ oli-atiir a^'i-m-ii-s may havi- cuni inin-il ai-tivi' itiliilln- I'liiii-i-Mi-. Ill ( alitiiniia ami Oii-nnn. ai-cnnliuu to I'l-ofi'ssiif I,r t mill'.- 1 1n- i;iral lava lluu s jinibably i-omiiiiiu-cil in In- iiiitpinii'il at till' bi-Lriiiiiitm <>( the I'li'ici-m- i-pnrh. as -liuwn by thi' I'ai-t that llii'si' lavas lii- iipiin i-rmli'il strata «il' .MiiM-.-nc aLTi-. Mnilil'yiii;: till' iliii-i-t i-\ iili-iirr nliiaim-il III iiirai'l in tin- ai;i- <>( iln- Alaskan basall by lln- siiiri^i'sl inns ih-riv i-d rroiii iii-iirhlinriti^' n-LMniis, \\i- ina> say that tlii'sr IhnNs may liaM- bi-uiia in Alaska in lat"- Min- i-i'iii-aiiil may lia\< n ai-lii-il into tin- i-ai'lii-r pai'l nl'ilii- ['h-isinri-iii'. siiiic I III- 1 Til pi mils a I ilill'i-iriil liii-alil lis \M-ii- nut nri-i'ssaiil> ■•niiti-m- liiirani'iilis. ami that tin- pi-i-iml ul' ^ii ali'sl aili\it\ was piist-^lini-i'in-. Ill . -lii till- i-asi-s i-iii-il tin- (lows si>i-ni inlnm- bi-i-n ii-laii\i-ly small anil local, ami nliiii. as -it tin- amiith nf tin- l*i'll.\- ami at >l. Mn liai'l, thi» lax a st-i-iiis In ha\ I- bi-rii piMln-il I'iniii i-raii-is arlivitv si-i'ius 111 111- ilisi iin-i I'liim tin- iiium havi- laUi'ii plai'i' alniii^' lln- Alaskan I'l-niiisiila anil tin- Mi-iitiati Islaiiils ami lailhi'i' iiilami alnii;; this saiin- asis in lln- ii-;;iiinsilraini<(l rius pi-riiiil III' \ nlcaiiir Ill I'i'iipl inns whii-h by till- ('nii| 111- Kivi-r. I'll i-sc iiini'i- li-ii-lil niit lili-aKs si-cin til III lai';;i-l,\ amli-sitii-. The Mili-aiin- ash alrcaily imii'il is il iilyi'\i- ili-nri- 111' i-iiinpaiai i\ i'l\ ri-i-i'iit Milranh- ;;rti\ii\ in tin- ii-yimi nt' tho I jipi'i' Viikiiti, ami ai-i'iii'iliiiL: in I >i'. lla.\ I's this ash was pruliably pi-n- iliu'i'd li\ an I 'I'll pi lull ill I III' III lit III- I'M pal t nl' t In- Si . I'.llas Mminlains, iii-ar 1 III' sniin-i 111' I III- Kliiilaii 'jlarli'i'. This lasi-naimil ri'v:iiiii may In- ciinsiili'i'i'il as tin- iimt Inasiiin i-ml nl' a /mii' nl' ri'i-i-nt vnh-anii- iK'tixitv whii-li I'liiis ri'iim this i'i<;;iiiii thi'iiiiu^h lln' Alaskan I'l'iiinsiila. •0|>. clt..p.!rB: MMniiMiTriii-i Hiy.il Sim- l'iiim.!ii. I'. V,.l. Vltl. -I'l- t. v 15. !.\iii Jiitir. 8il .3dwirlii«. V-.l XXXII p. ITT. Ex|ii-.Uli..ii 1I11..111/I1 lln- ^ iiK.1,1 .INti'i.f \ .1 il,'..K Milt- , V..I IV, |. ||». Ill :)i (• H A PI' K l{ I V. Mf)VK:*n:N rs IN iiii; i:Ai!iir>' < i;i>.i. It is inloiuled In siuiiiiiai'i/i' mulci' the licailliiu i-'i\<'ii mIiuM' all iiii|M)i ,aiil niovcnu'iils in liic rocks, iiiclii(iiii;r ii"t mily t'uliliin.' ainl faiilliiif;, l)iil also iiiliTslilia! movciiiciils, iiroiliiciiii,' schislnsiiy ami 1ii(! liki'; iiiitiral inns dl' molten I'ocks, pidrliiciliLr ilikcs ,'iii.|iiii'fii! aKui'C'ios, wiiicli ]»fo(liicc by iTosion ami ili'posit ion hilU aii uplift or dcpri-sslon of ;;icat ai'Oiis, iiikI IIh' folding: or faultinirof ;lii' snporficial rock--. ar(> prima- rily important, sini'r it is lai'LTi'ly upon these that the minor .idjiisl- liu'lits depend: and tl 'V will therefore lie eiiielly I'onsidered SUMMARY OK GEOLOGICAL RECORDS IN TiIK KOCKS. 'I'lii' features ot' i;enerai importance- in the history ot' the roeu tor- mat ions alotii.' the ^nild lielt in Al.iska an- --o far a-- impiMl'eet l\ Kihomi, a^ follows: 'The fnndaiuenlal rociv of t le rcLiion i- a scliisto>e ^ratiite, and Ixin;,' upon lliis is a thick seiies of schistose and often impure i|iiart/ile, whose situation and pet ro^iraphical eha,r;ictcrs iiidicale a |)rolialile derivation I'roiii I hi' irranile. The schj-.i- are also '.iraphit ie in place-,, 8iljii;estiiiLr the preseiu'c of oiiiaiiic life at this perioil. f.yiny- upon theso qiiart/.ite-sidiist--. which lia\i'l>cen called tlic IJirch (feck set ies, c'line thi(d^ lied> ot cr\ stalliiie inarhle inti'i'heddcd with • plait /.it c- Bchists lia\ iim' much Ihc same cliaiacier> as lii'l'orc. luit irrailiiiLT into inor<' Id^dily cryslalliiM' liornhlcndc and mica -chists. whicli f.irm finallva larp' pari of tin' rocks. 'I'hcsc hornltlendc- and iinca-schists ate often irii.philic, and ai'e evident 1\ deri\ed If (Mil ill! pine sediments. Above tills scries id' marbles, schistose (piail/.iles. ;iiid hornlilcndi'- aiid niica-scliists, which has been called the |''oitymile scries, comes u ti]vu\ Ihickiicss of basic voleanic rocks, alleiiial iii.u willi tiill's and impilie .scdilllelits. This lias been called the Uampart series. While the r.infli Creek and Kmf \ mile .series arc hi«lily scliisiosc, the |{am- pai't sorii'S is, on the whnle, massive, alliioimh geiiernll.\ Jointed and locally becomin.u sclilolosc aloiiL; 'leliiiiie /ones. <»ii the whole, ho«- e\er. tli<>re i- a marked contrast in de;;rec of meiamoipliisiu between tills and the pre. i diii'; f|.i. KIsllJli I, AI-ASKA trit'iitl,\ >lii'iii<-i| iiluii;: Willi llif iiii'lioiiii; rcick^; ;iliil lliiii' nvr i|ii;ulz veins which art- ^'riuTiillv |iiir.illrl In Ihr "-cliiNlosil \ . ainl "hirh also have siilTcrcil !_'ri'al shfariiiir. liisiiifs llic ^really shcaircl diki-s, there are (Pllieis wliieh -hnw less anil less iiietaiiiorpliisiii, ainl liiially SI line w lliell have lieeli elililel y II lia iVeel e( I liv ailN' «ly liaill ie ' I isl II ilia liee. The iiiassi\e dikes, when Ihey iii in I'lnsr iirnxliiiilx In I he nmre m less sellislnse mies, ill\ aiialilv slmw llieliisel\es In lie I he yiilin;;i'st, ipC 1 he silies. I'hese sal lie yollliv'esl i|ike>. or ilikes iif I he same | ||- liar l> |ies, are alsii rniiinl c'lii I in;; I he inek-. nl' liie i;ain|iail series. .\liii\e the Niileaiiie links aiiil iin|iiii'e seilinieiils <>( the i{ain|iai't series eiillie liinesluMes. shales, ami iieeasiulial eiilii^lonierales, whiill, ll'iiln waul 'if klliiwlei|f,'e silllieieiit lor I heir ilill'ereiil iat imi, liave lieeii ^iiill|ieil lonelher as the 'rahkainl it series. 'I'liis series eonlaiiis in (lilleieiit |iail> lo-sils. whieh iiiiliealelhal it Is in part ( 'arlioiiireioiis ami in |iart l)e\oniaii; liiit I hese are liol iieeessarily the liinils ol' I he ajie of Iheiiieks i iiel iiileil iimlerlliis elassi tieal ii ill. The 'rahkamlil, series show > in .1 malkeil ilel,'lee less ileeii||||iosil inn ami met a nil ir| ill i SI II than llie ltaiii|iai't •.erie>. ami the ill'' liel Ween I he t uo. a |iriilialile iinennl'iiiinil \ eNisl- .\lio\ <> III) ihkaililll series eoliies I he .Mission (leek series, vvliieli is, ill jial't at lea--t. (leta Us. .'iinl is inaile iijior Itlaek eaieaieoiis or rehls|iathie >liales. inijiiire thin lieihlcil liineslinie. yiii_\ samlstoiie, ami eoiiL'liimerale .'^eaiiis nl' impure inal anil oliseiire plaiil remains are iil'leli I'oliml. Inn oeeasiolial I'ossiN show the serie.s to ha\e lieell larv'i'l.N a marine formal ion. .\t the liase is a eoiitrioinerate, whieh lesis iinionfiiiiiialily on ilie Itampart series ami l-'oityinile si'iies, .iiiil roiilaiiis pelildes ilerived flolii these nicks. ■ Miove the .Mission ("reck scries eoilies a Ltreaf thickness of iiiassi\(' eoni,'|omeiates. uilh coarse ;,'iits jiiid some saiid.N. aitiillai'coiis liiiie- ese rocks contain aliiiinlant plant stone ami iminire >hal Til remain^ ;llii| occasional freshwater fauna, on the e\ idelice supplied li\ which ihev are relernd to the Koceiie Thei V are no marine los- sils or other e\ii|elice of lii.il ine colldil iollS. The ciili;;loini'rates coll- t.'iill pel Ides of the liaillpai't series. l'"orl \ mile series, liirch (reek seiiis, and of \arioiiis oilier sodiiiicntary and ijfiieous rocks. Tl IIS lileal thickness of flesh-WJlter lieds has lieell called the Keiiai serii The Tahkamlit series, Mission (.'reck scrio and the |\ci all show .'ilioiit the •^.inic .imoiini of il\ nan lai series -t iirliance. t here In ini.r app..i'entl\ rv ureal iincoiiformit \ >eparaliliu them from one another, and all h.'i\ iii^ heeii folded toHciln Sometimes these lolds ■n. Mini soini'iiineM cliiseh c III ate t;<>iitlc, soiiietiincs liiiiad and lircsid and \eiiical. (iwini^io this fohlliij! Ilieri' is local .juintliiit, lull all tin rocks have lieeii pniclicallv iiiialTccted li\ rc^rional ■•Ileal iiii;. 'I'hc Weds oM'ilyiiii; the Kcinil miljes are few and scull ered. <»n i he upper p.iil of Mi'sioii Creek arc partially consoliduti'd, iicarl.v lioij- m 38 II or; II, A I MiKvi r V Saclion on LihB A A KiGH^fTN^H ANNU'Vl HFPORT r'AP'" ^■», g^r.Mi Villi, .1, V .'/^ V /■ On, >^W f \ -v I.' >. .."•i^' ^ "mm A ,. .-■ J' ' Ullilis -r:,'' Poncu^iHf, DO*L 1 ' I X S - i ^ .■,i..ii7iisirv_tf„,^ 1MB A * !• . ,1 S r a I e !*l>l HU ] (IKiil.oi.li \|. MM' 2a3 /nlilal ii.Mu'liMMiiiil"'-. ;iliil LTlil- i;in\ llii; |il,'iiit ii-mimiIin, uIiicIi ;i|i|hm|' It) n nil 'si mild w ith I MM Is I. II till' I 'nil' II I li III' ;i III I Mjii'Uili/li' All I In si- M'iliiiii'iil> ail' |p|iiliiilil_\ liii'jil ai'iMiiiiiilalinio ill laUi's 111' liiiuiiil i'\li'iii. Till iM' III! I III' Mai'kfti/.ii'. « liii'li wi'ii' i-\aiiiiiii'i| li\ Mi Nii-< (iiiiiill. have Im'cii i'i'I'i'I'I'i'iI Ii,\ Sir Will ia III I >a\\ ••nil, nil 1 1 \ iilciu t 1 1||. ilmij w Incli lliry I'Diilaiii. Ill (III- l.araiiiii' (l-'nrt riiiuii u'i'iiii|>. m' Kui'i-in-. nt' I'liili'il Stairs ;ri'ii|iii,'i>t> ami nt' tlii'» ri'|iiiit 1; lint iIh'Ti' In >Iill r f,ir i h, .siisjtii'iiiii that tlii-y iiia,\ |iiii|iitIv Ih' a»siL.'iic(| tu ilir Niiiiiiiii'. TIh'sc lii'ils ill!' M'|iaiatfil li,\ a lindiiiiiiil iiiii'iiiilnriiiil \ fnnri llii' iiinli'iU iii^r Kfiiai M'lii'S, lifiii:.' milv ;.'i'iil|\ Iilti'il. while tlmsi' uf lln- ixi'iiai nil' sliafplv fiildfil. At llif {.ihmt Kaiiijiaiis an- i'iii-.s.li(.i|i|i'il sainl- stiiiii's with I'lissil li'iivcs. riiiii's. ami I'la^'ini'iiK nf wimmI TIh'm' Iii'i|> arc jinilialily I'lini'i'iii'. I''iiiall,\ rmiii' llir l'li'i>l in' ami ri'i-i'til hilts ami iiiiiM'ls. u liii'li an- srallcn-il ail nxi'i- I lie I'liiiiit ly as a ii'suli ol' ili'jiiisil iiiii ill I III' ;.'iral laki'saml lixi'is. GEOl.OOICAI. MAP It was tlii)i|i:lit Iti'sl til |iiit ii|iiin a maji i^i'i- I'l \\\\IIIiili(> ilil'iiriiialioli I'lilii'i'ti'il riiiii'rniiiiu' I lii' ;ri'ii|ii:ry nl thai |Hiiiiiiii ut' t Iit> (,'()li| lii'lt ill Alaska wliiili was I'xaiiiiinii in llif >iiiiiiiii'i nf I-^'.mI. Siiiiii' lii'silal imi was IVll in iloiiii.' I his mi ai-i'Diiiii nl' ilir rxliriin-lv liM'a;;i'i' aiiuiiiiit ti( ilala a\ ailalih'. < )ii I hi' ntlii'i' ha ml. I'l'i'taiii lirnail H(>i)li>f;irai I'ai'ts wliirli \m'ii' rli-arly priiNi'il li\ mir iii\ isi i;.r;,| i,,;,^ ,.,,|||,| not lie a|p|iri'iMali'il rimii wrillni i|i'si'ri|itiiiii-. almii'. Ill iii'iliT III iiiaki' I'li'ar llir atiiiiiiiil nf data rrinii vvhii'li dilVi'ii'iil jiiirt inns III' llii' iMa|i urii' iniisl iinli'd. an iiiii'uliii'rd lia^i' ina|i is pii'- wnli'd. (Sfc i'l. .\\.\l.\.| I >n this nia|i till- iiiiiii'-. w hii'li liaM' I n t ra\i'li'il liy iilisi'i'Vi'i's who have n;adi' iioli'S ciiiii'i'inini; the ;;i'iiliii;y are iiidiealed l>y eolored lines. The red eolDiinj; shows the tra\erse liiiide liy the I'liited states (H'olii;;ieal Survey party in I he siliiiiner of ]s;iii. |''or a ;;r(>at part nf tiie dislame traversed only extreinely liiirried and iinperl'eel r miiaissanee eoiild lie made, while ii rlaiii olher paiis, sueli as the {'"ortyniile and llinh (reek iiiinin;,^ di-.! rieis, iiiiiie earefnl thoimh still hurried work was done. The lirowii line shows the route lit' a hut lied reeonnaissanee liy .Mr. |{. (t. .Me( onnell. of the (aiiadian t ieoloLrieal SurM-y. 'i'lie yellow line is t he rniile t ra\ - er.sed liy .Mr. W. < »L'il\ ie, of the ( aiiadiaii i Jeoloirieal SiirMv, and eoii- eel'liin^t this I ;i Mi' Oy;il\ie lia-> made a few \ ery lirief notes. The blue lint- is the unite i.iveled liy Dr. liayes, who aeeompanied l.ieii- It'iiant Sehwall 1 m ms trip aloiiL' the While and ( opper ri\ers. Tlio fjreeii line ■- lie route folliiwed li\ l.leUleliaill .Mlell on the Taiiana and KoyiiKiik ri\eis. •oneerniny: whiih he has made one or two rather \a:,'in' ^eolii;rieal notes. The oraiiire line represents a I'oiii ineerniii;; wliieli some infuniiiit ion was oliiaiiied liy pros- peeiors, the information :ii\in by whom, liowe\er. is of doiilitfnl value, since liieir diseriminat ion of roeks is iioi alwa\s aei'iiiaie. I s IMAGE EVALUATION TEST TARGET (MT-3) 1.0 I.I Ik I* I. UUu 2.5 1^ I 2.0 11-25 i 1.4 1.6 Photographic Sciences Corporation 33 WEST MAIN STHET WfBSTfr N.Y. )45ao (716)173.4503 Jk^ ^,^> Ill . II OKOLOGY OF THE YUKON GOLD DISTRICT, ALAl^KA. Tlic iiil'i)iin;iti(iii iiidiciilcd jihovc is all that is aetually available coiiccriiiii^' the ^fcoldijy of t lio rcifioii inapiicd, and on tliis basis the nia[) has Ijccii constiMictod. Alonu- tlic I'onlcs (hdinoafod tlio observa- tions arc always r(»ugli and sonictiiiics niircliablo, and in llio intor- vciiiiii^ coiiMli'y llic frool((Lry, as inral- i/.ed. 'I'lie repi'cscntation of the relative ihickiu'sses of the dilTcrent formations has not been attempted, sii these ai-e not dellnitely kuown, and unconformities are not shown. < )nly the general st met ur(> and tho succession of the dilTorent series as roufrhly divided, and ns explained in the text, is ,t;iveii. The suinniit of the Yukon ueajiticlinc is shown on the left side of the section, and this chaiiffcs into a shallow geosj'iicline on tlie right side. Just northeasi of tlie Yukon the continuation of the ^laTninoth .Mountains foi'ms a scarp of youiijicr rocks facing tlie axis of the anti- cline. The country shown in the left of the section and in the corre- sponding area on the nui]) is represented ;.s being entirely of granite, since '.].■' only notes availal)le are tliose of Lieutenant Allen, who describes granite along the Tanana. It is the belief of the writer, however, that this structure as I'epi'cscnted is i)robably incorrect, and that younger rocks will eventually be found overlj'ing the granite neai- the Tanana or ininic(liately to the southwest of it, and that these younger rocks are on the southwest lind) of th(> Yukon geanticline. There ai'e as vet, however, no data for this belief. DIVISION OF ROCKS ACCORDING TO DYNAMIC DISTURBANCES. !« All the rock formations u'uy be roughly divided into three chief groups, according td the degree of dynamic disturbaiu-e which they have undergone. The first gi'oup consists of the mori^ or less schistose rocks, beginning with the fundamental granite and ending with the Kampart series; the second group consists of tho uushoared but often highly folded ro(;ks, beginning with tho Tahkaudit series and ending witli tlie Konai series; the third group consists of tho nearly horizon- tal and oidy partly consolidated sediments, beginning wit Ii the Twel ve- nule and Poi'cupine River beds and ending with tho icccnt gravels. These great groups are separated by great uiu'onformities, and althougli minor unconformities undoulMedly exist withiji tlio groups themselves, yel the\' do not apjiear to be of nearly the s;"ue im- portance. 39 1 1 \l n ,! H 1 i j i If 1 1i ii US GEOLOGICAL SURVEY MAf UK A KJKTION OF THE VTIKOiSr CiOLlJ HF.LT .WD ADJACEI NOTES ll.WK BEEN Suale .,{ Mile!. fpf^^ EIGHTEENTH ANNUAL REPORT PART 111 PLATE XXXIX. )LD HKLT AXl) ADJACENT REG10N8, SHOWIXci LINKS ALONG WHICH -IKOLOUIC Nf)TKS HAVE BEEN MADE Uuale . nl' ilic idck I'oimim- tions, may be interprote admixlui'c of olhcf i^fanitic niatciiai. 'riic iiiicikm' of •ria|iliitc in tliosc no\v-mc1amoi'iilioscd sediments siii^'u'ests tliei)resen if life ibifinj; their ile|)osiii()ii. Alio\(> these siindstones were laiii (hiwn thicjc beds of limestone alteiiiat ini; wit h sandstones and more imjinie sedimenls, often liij;iiiy earl)onaceoiis. 'J'lie tliiekest beds of linie- stono were deposited immediately alio\-e the samlslones. while in the upper iiai'l of tlie series impnr<' (let rital rocks became nioi'c al>niidanl . All these sodimeids seem to lie npon one another, so t'ai' as yet observed, conformably; and the accumulation of so j,'reat a thiekm'ss of conformable strata ma.v be taken to i-cpicsent a loni;' pci'iod of nearly utuform conditions. 'I'lie t ransition of the j'.irch (reek quartz- ifes to the Fortymile marbl<>s nia,\' represent ,1,'eiicral depression and frequent immunity from land se(limeiits, and the increasing' airioniit of impure sediments at the top of the l'"ortymile sei'ies may indicate rcelevation. This long period of ([uiet, with oid,v uniform and widespicad cruslal movemont.s, was brought Io a close by a series of great disturlianecs, which lasLcd for a long while, '{'he earliest numifestal ion of these disturbances appears Io have been the intrusion of molten roelc from below, fornung dikes cutting tlie sedimenlaries. At about Ihesame time movements in the crust brought the rocks under great strain, which was relieved by the slipping of grain u])oii grain, and of one laj"er on another along bedding planes and other lines ot' weakness, and finally by the product ir slicarinn -^vas iiidnci'd : hut I lie vcnicnls I'oUowcil wlialcvcr planes «(■;•• loi-iliy liie weal- est, and tliese appear 1o have been K<'ii'"ii'II.V tliehe(l(lin;>l)lanes. The eviilenee ol" this isctiiedy found in Die l'"orfy- inile disli'iel, wliere tlie seliislosity is everywhere ivjiuhir and parallel to Ihe true iieildin;;'. the lattei' heinu shown by the alternation of niarhle with sell! sis. tlioiiirh it is shown also iii Ihe l.irch ("reek dislriet, wlier(> the seliistosily, so far as ohservcd, seems to he a {food index of struct nie and of the relations of t he dill'erent schistose series to one another. It thus lia|)pens that the schists on I'^orlyniih' ('re(d< and to tluM-ast alonjr the Yukon have a general east-west, strike — cor- respctudinj; to the east-west folding shown liy the succession of foruui- tion.s^but a vai-yiufi: ili[i. On P.irch Creek, however, the foldinj^ is niori' };;entle, as seen on the map. \"ei'y early in the period of dist urbanct' narrow (juartz veins wci'C formed in all the rocks '■liercM-r tlie dynamic stresses i^roduoed open cracks or /.ones of weakness, which naturally becanH> water channels. WluM'c no previous special .system of planes of weakness e.Niste(l, the channcds thus produced by dynamic stress wcu'e relati\'ely few, as is 11u> case in the nuissive marble of the Fortynule sei'ies. In the more definitely layei'ed .sedimentary rocks, liowevor, such as the ([uartzitos of tlw r.ii'ch Creek sei'ies, and es[)ecially the impure schists of the Fortymile series, the pressure-producing' movement along the weak bedding phines made tln'm still more available as water channels. Therefore, i)i the basal granite and in tlie nuissive marbles, the quartz veins ai'e relativtdy few, but they are abundant in the more definitely layered rocks. As nuiy be infcrrinl from what has been said, lliey ari> usually conformable to the schistosity of the rock.s in wliich they occui', but occasionally they are found cutting iicross the la.vers. 'I'he.se veins are genei'ally narrow antl noiipersistent, ami are often merely elongated lenses, as if foi'ming in cracks left by the si>reading ajiart of layers under stress. It has already been mentioned that these schists are cut by ii series of dikes of dill'erent ages, of which the successively younger show less ami less shearing. Tlr ■ is an evidence that the devolo[)inent of schistosity was very gradual, and much other evidence confirms this conclusion. By the continuance of tlie shearing process, features which were developeil as the conseiiiuMice of the lirsti movement were altered or oei^asionally obliterated. The earliest dikes become .schis- tose find the quartz veins became stretched or juilled into shreds; and metamorphic minerals, such as garnet, were crushed and eloii- gateil along new slipiiiiig planes. fJ.V.AIl'AHT SKRIES. Near the end of the long period of disturbance \V(>re eru])tions of basaltic lavaover a great area: sheets of vast thickness and extent were poured out. 31uch of this lava must have been poured out in 'ill siiiui.) MOVr.MKNTS IN IIIK r.MMIIs CHI-I'. 2.'7 till' ^c.-i. I'lir llii' ^liccl.s wi'i'c .iiipaic'iil ly iimnriliali-lv cciv-cn-d ii|i liv I litis Mini lit 111 T M'llilllcllts. 'rill'-.c clVll-inlls uciMIIIi'il lc'| li-.l 1 ( ■> 1 1 y lor it Iciiiii'l iiiii'. .iiiil ill llii' iii1i'r\als licl WITH lliciii si'iliinfiils ai-fiiiniilalccl, sdiiirliiiics imhii|mpsc(| ciil iri'ly III' volcanic iiialcrial. I ml iriacjiially iiinw- iiiL;' |iiirci-, ri>riiiiimiiii|purcsaiii|s!iiiics. slialc-.. and liiiic-liiiic^. In I hcsc |)ci'ic»ls. also, soinc lilV cvislcil. as is siinwn liy lisji icclli (iisco\ci-ci| iiiicroscopiciiUy in mn' of ilic specimens ol' alicicd ^:laiii'oiiil ic liiiic- sioncs. Owinn' 1o 1 lie i;i'cal I liii-kiicss of .some ol' I he lava slici-ts, liic texiiii-e III' ilie rocU is fieiiei'ally I'oiiiparal ivcly coarso, so lliat llie coarse \ai'iel ies have lieeji descrilied as d ia hase a nd the « lioje scries lias lieeii cliai'acleii/.e(| as liasall ic dialiasc; I liese iiriieoiis rocUs and asscieialed sedimc'lltaries lia\e lieeli i;r(mped toirelller Under t he head of the l{aiii[)ai-l series. 'I'lie liaiiipai't series is only locally schislose. an lia\ e heen relie\ed liy it; hill t he prod net ion of t he Joi III inn a lid local shearinii may he ascrilie(l to the last elVccis of t his reijional sii'ain. Xomcal niiconlurmity has l)e('ii ohsei'vi'd helween the T'orlymile scries and tlie ]{ain|iart series; and alt liouiih it is prohalile from the iniiniicrof their f(n"iialion that some dcn'rcc of unconformity exists, yc-l ii seems that the movcnicnt which prodiiccij the cast-wi'st folds in the older ro(d;s did not culminate until al'tci' the end of the formal ion of iln' I'aiiiliart series, since on l''oriymilc ('re(d< and elseuheiv tile latlci' seems to l;a\'e heen atl'ecled 1p\' this svslcni of fojdini;'. HISTORY I-'ROIVI RAMPART SERIES TO END OF KENAI SERIES. .Vflerlhe formal ion of tin' liamparl si'ries caiiie i he deposit ion uf thick heels of liiiieslolies, shales, ami occasional coni^iomcrates. uhich ha\ c heen calleil 1 he Tahkandit series. This incliKles rocks laid dou n in l)e\(iiiian and in C'arhonil'ennis lime, ami may iiidinh' rocks oldi^r or yomm'er than these periods. In the ]H-olial)le Devonian strata below .Myiiook Creek smiie plant reiiiains were found in the shales assiH'ialed with limestones, indicat in;;' occasional |)ro.\imity lo land. On the ^■||kllll heiwecn Mission Ci'eek and Circle City. Carboniferous fossils occur ill limestone interbeddecl uilh coniilomcrale u hose pel i- bh's are mostly of chert of \arious brii;ht colors, and espcciall.\' of a deep ureen. like the eherls which ha\f formed in llie rocks of the Hamparl series. These I'oniilinneralcs siiy^'cst laml in llie imiiieiliale vicinity, aii iPivn.'icr, ai.aska. •Mini' i|i':;'nT: w in Ir till' .Mis-.i(iil ( liM'k >c-lirs III \,lliiills |il;iiT \\,l« •II 111 yi"-\ ii|Miii t he l!iiiii|paii --c' ill IIIMlki'il lllll'iinrill'lllil \ . 'I'lir « ii?< |irul);ilil,\ , linw c \ IT. a >li.L;lil iiiiciinrciniiil \ lii'tuci'ii I lie 'I'aliUiiiiilii ami llii' Mi^siciii deck si-rics, as lia> alicail.v Ihtm sialcil. Un ihr illulr. l|(i\Vr\rl', lln' 'I'allk scllo \M i-f laii alikaiiilil, I 111' .Mi»iiiii Crrck ami llic Kniai iiic n|Miii llii' iiilii'i'. iimli'i' ('iiiii|iai'al i\ <'l,\ iini- riinii ciiiKliliiiiiN ami willi iioyrral (list iirliaiircs: .suit .scfinslhal llir loiii;- licriixl III' ilisi iiiliaiicr."- wliii'li lii'uaii uilli the sli('ariii,ir. roiiliiiu. ami iiil I'lisiiMi III' iliki's III llii' l''iiil \iiiiir series ami oilier rucks ciiilfd u II li I lie ell II >lc 11 1 111 I lie \ iileallie Idi ks 1)1 1 lie liaiiiiiarl scrii Tile rucks III' ihe 'ralikamlll series arc marine scclliiiciils. wiili neca- iiiiii plain reiiialiis ami cniii^liiiiieralcs siiiiyesl liii; llttural . v^lili maii\ la\er> iil' iiii|iiirc coal ami aliiiii series cuiilaiiis marine I'lissils. su llial we iiia\ enn- clmlc I liai I lie nicks were laiil ilmvii In I lie xichiil y of I lie la ml, siiinc- liiiicsln llie sea ami siimetlnio In Iresli \\alci': anil rnnii the usual \er\ tine iiiaiii nf the material In the rucks, cnisinii ami rt VIII lie. Ihe IJircli Creek, and the Uampart series, as well ;raiilte and ol h r lyiieoiis and scdlnieiitary rocks. (out last I nu' the evidence oll'ered hy the 'rahkijmlil series vv Itli that of the Mission Creek series. v\ e may assiinie a .;;ciieral eh'vatlun lictwi'cn till' ilepusitluii of the I'ormer and of the latter, so that fresli- waler lieds and evidences of land proximity hecunie iiiiich mure alinndaiit. .\t the end of Ihe dcpuslllun uf the .Mission Creek scries there must have liccii .-i marked cicvalion and the forniatlon of a liluh land mass which was v lolcntly attacked hy erosion and rapidly dea'i'adcd. The material thus removed v»as laid down In hudles of fresh water, formlni;' an immense thickness ol' sediments in a coni- parativ'elv short time, p'rum the cumpusltiuii uf these scdlmcnls. it Mpjicars that the 1 Jam pari series funned an I m purl ant part i>\' the land mass, while all the rucks ulder than this series must alsu have liecii e.\po.sed, ami i)i'uljaljly rucks bdoiiyiiig to vuiin.u'cr foniiatiuiis. MoVr.MKNIS IN Tin; I-.AIMII > CK'I-I. 2.-)^ THE POST-KENAI REVOLUTION. A I I 111' I'll! I (iT Ki'iiai I iiiH' I lici'i- uiTi' iihpv c'iiiciil> "I ;:rcai iiii|HiiIaiii-i' III 1 lie c-ni>1 111' I lie I'.-irl li, I III' iiiii>l ri'iiiarUalili' i-i'-ul! nl w liirli ua'^ a S('l'ir> III' Mi'\nii'> III' \ a>l ilillli'll-iiill-. u lllrli lia\ I' \ I'lX Inlii;' null liui'-l jiMil Mini lira^t a\i'>. i M' i Iitm' I'uliN l hr liol kimu ii lia» lici-ii nai 1 till' Niikiiii u'caiil ii'lini'. Almii; llir a\i> nl' iIun I'uIiI IIh' riiiiilaiin'iilal i;raiiili' I'Xli'iuN ri'iiiii I In- Taiiaiia almiu' I In' \ ilk mi anil I'i'llv as lar a-- Ihi' |)i'aM' IJiM'i'. a ilislaiii'i' uf iii'arl> >!"' iiiili'^ in a ^li'aii;lil liiii', OVcl'lylim lllis iiiailili' In tilr null lli'a>l ami Ik llli' Milllliui'^! I'lillii' (|iiai'l/.ili'-sctiisls and iiiarMcs liclniiiiini;' In 1 lie llii'di ( "ri'rU ami I'mi \ mill' --I'l'ii's. anil l.\ iiii; ninin \\\vm' ajraiii, at a iiiuri' I'l'iimli' ilisiann' rimn I lie uraiiii ir a\i>. an' si ill > unnui'i' rm-ks. < tiir kiinu Inlu'i' nl' i Ih' siir- cession 1)1' si ra I a mi I lie siuil Ii\m'--I -iilr nl' ' lii' I'nlil ili'|ii'iii|> niainlv mi tile nnlcs niaili' li.\ I'r. Ilaxi's in his liavcrsi' ainn;.;- llii' W'liili' ami ('iippi'i' i'i\('i's.' (>ii till' iinrllii'asl siiii" of till' fill. 1, hiiui'S IT. tlii'siii'- I'l'ssinll lias lici'li innl'c rari'l'llllv iilis('i'\ I'll, anil lia^ ln'Cll ili'snijn'd ill I III' iiii'i'i'iliim' pay'i's. Till' siiccfssinii 111' rm'iiialimis mi Imi h siilrs ni' ihi' i^raiiilii' bi'll is lliai lyiilcal of an aiil iclinal riiluv. Ii i- pinlialili- lliai lllis ucaiilii'linc iliniinislii's rapiillx' ni'ai-llii' pmai wlii'ii' il nils llii' ^■llkml at liii' l.nvM'i' Kaiiipai'is. ami linally ilii's mil. .\s a ui'iii'i'al iiili', ilir ilip III' lilt' rni-ks nil lintli siili's 111' ! Ill' L;i'anl i- I'liiii' isawa.N rrniii I In' .i;raiii1 if axis. 'I'liis is I'spi'cially well shown in llu' rni'inalimis wliirh an' ymiiiui'i- than lln' Kainparl sitIcs. sincH Ihcsi' lia\i' lii'i'ii lillli' 111' mil at all alVci-ti'il li.\ llir I'asl -wrsl -I ri'iiil- in^- rnlds wliifh arc I'.vhiliiii'il li\ lln' IJaniparl ami uMit nirks. 'riic \-nmi,i;'('i rocks, llicn'rnrc, shnw in llicir si riici nn' simply ami clearly ilic cITi'cis III' llic posl-Kcnai rcMilnlimi. On llic ri^i'ht siilc of Ihc Viikmi. hcUvci'ii i''iirt\ mile I'nsi ami Circle Ciiy. Ihesc yoiin;;'er scries are cxposcil in sliai'j niitains in wiiich the ircml of Ihc si rata cor- respomls with llial of the raiin'c. ami the dip appears lo he nnifornily In ihe nnrtheasl. smneliines at a cmiiiiaral ively m'lil le anulc soinc- tiliies licarl.\ verlical. iicsiilcs the ^'llkon iicanticliiic there arc iirolialilx' oilier ureal folds havinu Ihc same .ncneral Ireml. The exisieiicc nf a -cnsyneline lyiiii;- iinnicdialely northeast of Ihe Viikmi i;cani ielinc and liavini; the same liclieral trend is indicalcd on ihe map of Ihe pild hell, hut this rcinv- selilatimi of sirilclnrc n'sis on very sli-hl inforinal ion. NEOCENE MOVEMEN'i'S. Ill Ihe period siiecccdin.u' the posl-l\i'liai I'l'Vohit ion Ihc Lncater pari of .Maska seems to have lieeii land. Alon.i; Ihc l.nwer Viikmi. in the vieinily ni Niilaln. are marine limcsi s and impure sandsinncs. 'I'licsc are rip|ilc-niarkcil and cniss-licdilcd. and i lam plain rema.ins. '} •_'(!() (ll.iil.iKiV t>l' llir. VI'KON (i(iMi IIISIIMCT. ALASKA. iiinl Mil' llicrc'l'dn' |iriilpMlily .1 lillnr.il rdriiuil inn. In I lir rcyii.ii I'iiil Iht Moll lii';t>l iIhtc is :in aliM'lii'c "T iiiiii'iiii' scilinii-nl>, liiil tln'i'c .-irc (M'iMNiiiMiil rrcsli-wiiiiT ImmIs. inilii'iitirii:- II laml surfju-f w iih nniMi'inns Ijikcs. wlijcli may In- I'i'rcriol In llic sji pi'iiml as tlic inaiinc saml- slipiH's a I Nulalip. hiii'lML' lliis |i(ii("l \\\i- la ml sui lacf was itimIimI ami the axiscil' ihc ^■||klln ;;i-anl idinc was unrn ijnw n. cNiiosinu- ilic(]|il rcicks in a Inciail Im'Ii with I he ;;faiii'al I'cci'ssiun nl'llic yiinriizci' I'cii'Mia- I ions. 'I'lic Mirt'ac'c <>r iildi'!- I'ipcks lii'caMM' in process (if lirm' snincilhcil <|ou II ami li'M'lril, anil llii' slopes I aine n'cnl le. so llial 1lie ri\cis iiieamiered I Ip'oiiyli iiioail. shallow \alleys. The imperreei plateau thus ]i|-o(lllee(| has lieell ealleil I he Ilileli')!' IMalea II. ami si ieleliesn\ ri' llie ;,'ri>atei' pari of .Maska ami !>iitish ( olninhia. l''roiii an eleNaled poiiil of view, il apii"ars like a ueiilly iimliilal iiii; plain, from whieli rise hills ami inoiinla'ns of no i;real heiulil . in I his plain ha\ e lieen (•III Ihepr-'seiil deep ri\cr \ alleys, as a eoiisi'ipii'iiee ol' ihe Neocene elovalioii. NNJilcli will lie releried lo laler on. MAMMiilH \l(i|\l.\l.\S. I'rom i-'orlyiiiile ( 'ri'id^ lolhe Kaiidik K'i\er there is. on the liyhl side of the ^■||kon. a rani;c ot' tall sierras risiiii;- from :;.niHi to ."1,0011 feet al)o\(' the ri\er. wliieh (lowsi'lose to tiieir liase; on the left side ol' the ri\er is the usual hroad. iii'arly lc\el plateau at an cle\;ition of several hum I red feet. I'roiii I he top of t his plaleall t here is ;i U' IJeral level ohsel'Valile lictweeli the tops of the peaks on the liiiiit si(|eiif the ri\'i'r. yet these peaks are so sharp as to present a yreat <'ontrast. with the ^reiitle topourapliy of the ]plaleaii I'oiinlry. 'I'he raii;;e has a ii'eiieral norlhwcsl trend, ( iirrespomljni;- with that oltlie rixcr: il w;is (irsi noticed in'ar {''ortymile Creek, ami from there cont iniioiisly to the is'amlik. lie low t he Kamlik I he V iikoii t urns to the east ami t he raii.iic st ill continuing' its mn-lhwi'si t rend, di\ erues from thi'ri\ci' and is lost siu'ht of. i'"rom the aliiimlaiice of the remains of i he fossil elephant ormanimolh in tliisrenion il is proposed to call thisiaiiue tlie. Mamniol h Moiinlains. I''ii;'. is is a \ lew (if t ne liiuhest peak iioled ill ihisranu'e. which has already lieeii iiaiiuMl Kathiil .Mountain, and issitiiateil a sliinM distance alioNc t he Kandik. I'riMH t he ri\('r these imninlaiiis appear as a ri(l,u:e of nearl,\' u 11 i form ma.ximiiin heiirht, hut carved into low. serrated peaks of hare i'o(dv, usually dark red in c(i|(ir, with lar,i;e liands of linlit li'rax . which are more resistant to w eat hcriiiL;', ami so form jiinnacles. The yray lielts maintain a nniforni posiiion for miles aloii.u' the side of t he ridu'c. and tlicrel'ore the roidis lia\e a strike conformiiifj; to the trend of tiie inoiiiitains. naimdy. northwest and soiiiheast. Ihdow l'"ortymile post, a short distance the dip appears to he uniformly to the northeast at an aii.u'le of ->> or imn'c. Near the international lioiindary these imMintaiiis were (diiiihed hy rrof. I. ('. Kiissell.' and were found to he about o.dnii feet ahoNc Ihe ' .\.it..>Mii tiw Siirliiii' iJ,.,,l,,iry .if .Vla.-kii Bull (i.-..l S..... Ain.Ti.:i. V..I I. j. rui TV M'tldl.) NK<>( i;nk mii\ i;mi;\|s. Ml ii\ir. Al till' ])l;icc \i>iicil ihccrcsl ol' llir ran;.'!' i'iiii>isi(.il ,,f rcmi' piiri. c'iirlliv liiiicsloiic ill iMMily vcitiriil slfai.i. -iiikiiiu' ''"iirmiiialilv w iili t lii> ti'i'iiil III' I III' niiiiiiiiaiiiN. 'rill- Tall III! I lie i> (Plir (pT I lie si ri.aiii> u liicli llnws l ||i(ini;li I he Maiii- iniiili Miiiiiilaiii"-, i'iiii'rin_ ilif ^ iiKnii mi ilic iiL;lii ^Idc. \|i. \\ . (»i:il\i<'' i'i'|inriN ilial llir mi'lo almi:; iliis ii\ ct aii' daik sliali's ci\ I'l - lain !>>' rnn'-,uraiiii'ii I'uiiiildiiicralo ami iiiiclcilaiii li\ ;;rayisli j'alcu. /(lie lillloldlM'S. I'l'iiiM this inrdniiatiiiii ii a|i|ii'ai'>> iliai llii' Maiaiiinlli raiiur i.'^m- |iiisim| 111 till' yciuiiuiT iiic-k-. ami. a> >ctii un ihc iiia|i, lln' imiiii,iaiii-< l\ iiiu clcisi' 1(1 till' ^'ukllll arc rnniicil ul'llial |iiiil imi df ilir vdiiiiijcr I kswiiii-li lio inn liali'l\ aii.iai'i'iil in llir una w 1 ' llic ..i.S'i- l*'ni. l>^, - Kjitlinl .Alniiiitiiin. !\r:iniin"f!i Kaiiei'. scrii-s all' I'liic'lly r\|Hi-.cMl. In ullicr Wdii|>. llii'--i' iiidiiiilaiii> a|i|M'ar 111 111' an rriisidii M-arp dl' t lie \ iniimiT riirk^ larini; t lie hIiIit series svliieli lie nearer ilie a\i> nl' llie ^ nkmi i:eaiil irliiie. i>i;ainai.1': s^^■|■|••.^l. The ^'nkllll lti\ er lldws aldii;; ihe Iddl III' tile Ma mil mill .Miniiitain--, uhieli |iriilial>ly eiiiisiiliite, as alreailv saiil. a si-ar|) iiC I'l'iisinn. The |iarallelisiii nf the ii\ei- In the avis 111' I'lililiiie ami its iid-itiini al the I'lidt 111' the miiinilaiii searp siiu'jesl thai il iiia\ lie p/i-iarily ilne In the I'dhlini;'. il' this is the case it is pinhalile that the iiriuinal liiienl' drainage uas parallel In the present mie. Init was lieLrmi I'art her ^din h- ' Ann. li.-pl ll.'..l. Xal lli-t Surv.x lalKi.lM, l-.-> .-i. Vol IV. p K-[) I l'(;-_» (;i;ni,(i(;v Irace clearly mily llmse e\eiils w hich were III' Ihe \ cry i;rea I esl iiii|inrlaiice, while Ihe inliinr mics remain llllklinwii nr can al liesi he nlily cnii jeel iired. .\s mnderii L;eip|(Pi;ica 1 lime is ap|irnMchei|. ImweM'r, Ihe r ids liecnine more Miimeripiis ami I heir mcaiiini; is more e\ ideiil . I'll lis. nl' I he e\ enls in Ihe cnnr mniis leni:lli of lime which elapsed lielwecn Ihe lirsl scdimeiils nn Ihe lia.sal u'l'iinile and I he lieninniiin; nl' I he Tcri iary we lia\ e heen a Me in nITeronly I he loiii;hesl sketch. < )( 'I'erl iary I line, hnwc\ er, inileh more delail can lie pri'scnied, and Ihe ceoloLrieal record inerea.ses in perfec- I inn lip In ihe prescnl day, when we may see Ihe prncesses nl' cllMlli;e cnilli; nn liel'nre iplll' eye.s. ( *nc III' I he means liy w hich we arc enaliled III I rai'c earl II iiin\ emcnis in ninre recelil Jienlnuical lillics is pliy.slo;j:i-aphic i|e\ elopmcnl . We lia\c alreadx seen linw Ihe cmnparalively Icxel inlerinr phileau willi iis aiicicnl liroad, shallow valleys, and moiinlains ;fi'eai ly reduced liy cripsiipii. poinis lo I he si alii lily of the land for a Imii;' period siil»se(|iieiii In the Keriai re\ nlul ion. dnrillfr W iliell period at mospherie I'olces weie al work. In Ihe same manner Ihc deep, eaiiMiiidike \alle\s in which -Ct )ll( I Ni:(li km; MuVKMlAIS. 263 HI: .'•t'ii ■-, il I lie I in 'SI '11 1 si I CM MS IlliW I I'll 111 III M llrriilpll ,'11 II I liilr^ riilll i lllli'il r|i>\ il- I lull III' I hr In III I ;il I III' rml I'l I Ills I II 'I'll II I III' stiiliilii \ . Till' I' II I till :^ nf I lli'si' ilri'li \ ;llli'> s mIiHiu; llli' lilli's iil' I lii' nlil s|imiiis|| i||-:iiii,-|'^r Innk phici'. ii\ I'l' I III' will ill' III' Al.-iskil, Ml Till' :is U I II iw II, ,11 111 i-iili 111- 1\ plailii'il iiiiU li\ sii|i|)i)siMi; ,'i ui 'I II Til I I'li'V ,'il iiiii u III I'll Inw i-ii'il I III- mil Ills III' l In- ii\ ITS, Mini SI I I in mil; III .iliniil rapiil ilri'iii'iiiim nf I In- ili-,iiii:iL;i' I'li.iiiiii'ls; ;illil silU'c llii'sc \iillllj;i'l' \,illr\s .III' iil'li'li si'xrral lillliijn'il I'ril i|i'i'|i, I lie iii'W ('( nil li lion III' alVaiis iiiiisl li'i\ i' lasti'ij I'lii' a Imr,: i iiiii' /'. r II 1(1 III I h rill inn. W c ma V Ih'IIi'M' I lial I liis i'|i'\ al imi limk plan' ill la 1 1' Miiii'i'iii' III' I'arlv I'll 'IH' I iiiii's. I'lir I lir mai-iiH' \|iiii'i'iii' saiiil- siniii's ill I III' \ iriiiil V III' \ iilalii ami laKi' lii'iN sin-h as i In- 'I'u rl \ !■ mile lii'ijs al llii' lii'ail nl' .Missimi ('ri'i'k liavi' ln'iii lillnl ami Im-ally I'lilili'il, wliili' \ iiilliiii'i' ili'piisils an- s|i^|il|\ 111- mil al all ilisi iiilii'il. Miii'i'iiM'i'. I III' 'i'wi'iv I'liiilr lii'ils slanil al an i'li'\ al imi anil in a pusii mii uilli I'l'^^anl II' llii' prrsrnl liraiiiaLii' wliirli slmus a Ihiil: priiml I'l' iTiisiiiii sini'i' lai'Mslrinr i-unilil imis ui-n- possilili-. ami iIh' mann'' saiiilsliiii"s an' i|i'i'pl\ I'liI iiiln liy 1 In' I.'i\m-I' N' nknn. sn ihala lai'L;i' pari III' 1 1 nisiiiii III' I III' i-i\ it \ alli'\ lias la ki'ii plai-i' sim-i- I lii-ir ili-p iisil iiiii ami i'l('\ al inn inln a pari nl I In- la ml mass, (in I lir ul lii-r liaml. 1 lii'sr \ allr.\ s i'\isti'i| ill prai'i ii'ally I licir pii'si'iil i-ninlil inn pri'viniisiu I III' ( JIai'ial pi'i'inil. I'lir I lie I'V iilci is a I mm Ian I I lial I In- Inlii's ul' i In' I 'I in li III' ran iilarii'i' i npii'il I In' \ alli'>s nl' I In- I'ppi'i- N' iiknii am' nl In-i- sli'cain.s ulicn llir.\ ucri' in prarl ical l,\ lln' sail mlilinii as miw, ami nil I III' ri'lrral nl' I lie ulai'ii'r lakrs urri' rnrim-il. u liirli iinw iii-i-npy pnrliniis nl' ll Ill \alli'.\s wliirli liaM' Ih-i'Ii ilainiii.'i! nr s|i^||lly ilcpri'ssi'il. . \'iilviiiiir iiiliiili/. Al alinill. till' saiiii' i;i'iii'ial pi'iiml i-a inp- liniisol' Itasall rrniii iiiaii\ sralli'i'cil siinn-i's. 'I'lii'si' Mnws ui-n- limii.-il ill si/c, ami wrri' usually rrniii xnli'anii- \i-iils. ll lias aln-ailv I n siltiursli'il rrniii inili'pcmli'lil i'\ iili'iiri- llial I lii-sr rriipl imis Innk plai-f llinslh ill I'linci'Mc llllic, u llii'lM\as illsii III!' pcriml nl' I 111' ai'l i M' i Inw n I'lillint;' III' llii' prcsclil \alli'\s. Sniiii' nl' lllc llnws appi'iir In lia\i' ilammi'il up llir \ alleys, as al IIh' J 'linn nl' llir I 'i'l I \ ami tin- L.'wi's ami al M ilrs ( aiivnii. Iii'l wi'rn l.akr l.i'liarm- ami l.aki- Marsli. m-i ai III,- inni-linll 111' I 111' I 'i'l I \ I 111' xallry nl' I In- Lrwrs has lii'i'll i'\i'a \ alnl :;iiu 111- liMi I'l 'I'! Iicluw I lie liasall plalcan siiii'i' 1 1 IViisinii nl' Ilir la\ a. Till' I'liiirsr 111' llic l.nucr \iiknii lii'lwi'cii llii' Knyiikilk ami lln-sra may III' ilili' I ll Iilili'ialimi nl' IIh' aiirii'iil \alli'\ li\a la\a llnu ; hill ill Ilir Kn\ iikiik .Miiiiiiiaiii llii' liasall lias, siiliscipii'iil In ils lOn sinii. Ih'I'Ii I' 'I'M-il liy llic I'l'iisinii nl' llic rivi'i' inln a pcrpi'inlimilar lilnll' III' TllM 1)1- SIM li'i'l. Ill llii'si' inslanri's ll i'llplinlis sri'in in lia\i' ni-ciirn'il iliiriii.u- Mii' cM-avalinii ni' lln' \ all<'.\ s. ami w<' may lii'lii'V i' llial X'nlcanii' aclivilx' lii'tran al appn>\iliialfl,\ lln' saim' linn' asllir ;;'('nt'ral clcvalinii. M'ninr liililniij. Alniii;' llii' ^'llknll lii-l -.M-i'ii l-'iii-lymi li' ( ri'i'k ami Circli' <'il\. wln-ri' lln' rixi'r I'nllnws 1 hr liasi' nl' lln' M; nnlli Mniiii- i'i A :.- '■I i|!i. A I l'(i4 (iKOl.OliV OF rilK VIKOX (KJl.D DISTRICT. ALASKA. liiiiis. Ilic voiiiiLCi'i' idi'ks. silcli ii^ llic 'riiliUandil, the .Mi.-.siiiii Cicck. iiiiil tlic K'friai scries, liavi' sciiiii'l iiiios a iicaily uiiii'orm atlitiidc I'ui a (•(iiisi(lcial)li' ili^taiicc, hiil arraaaiii llirowii iiiiu folds, ol'ii'ii sliaijily cDiniprcssrd ami vciMical. 'I'licrc is soimc sliulil t'aulliiiu' ai'ciiiiipaiiyiim this rol- rcMiarkaldc. In sonic cases (liose folds are so recent Ilia I 1lie\ a]i|iear on the Mirl'ace and deleniiiiie tlie |present to|)oi;-ra|(liy. .\n iiislance of lliis is .slioun in lii:. I'.L wliicli is a pliotouraiili ol' prolpalilv t'arhoiii fere MIS rocks on t lie riiiiil side of 1 he ^'iikoii, neart lie Tali k and it ]ii\('r. A broad band of w Idle cryslalliiie linii sloii,- makes tlic s! iiic- 1 lire ob\ ions even fro in a distance and shows t lial I he beds are bent !illl Fi(^ r.i.— Aiitiiliual iiillaipl -.Miclin;!! valley 1.11 Yuk-ii lln . i- ii. ai- hl.^uiI, ..i ■rnlikiiiiilit Hivcr. into an anticline and syiicline. 'I'lie anticline biriiis a hill and the syiicliiie a valley, the limits of these to|io,ura|iliic features corres|)ond- iliy- closely In those of I he folds. .Mr. K. (i. .McCom.cll' notes a similai occurrence on the l'orcii|iiiic. below Driftwood Kivor. Here lliere was obsei'M-d a sudden aiil icliiie which showed hard (|iiarlzites and sandstones o\erlyii,,u' coiii|iacl, bluish, soinetinies slialy, linieslonc. This aiilii'linal swcd jirojccls abo\'.' the surface as a hill, and the curve of the strata is si ill unbroken by deimdal ioii, althou.uh the fraclured condition of llio beds shows thai lliey were bent, near the surface and no! under any lireat pressure, 'Ami K.'ri. (ic.l. \:it. Hist Siirvrv Ciiiiihlii. V.il. IV, isss-mi. p. l-;iili. Mm -="i:| , 1 (■ ! F'*l: 1 I : 1 ■ m 1 s - II sprim.l Pl.KiyrdCKNK MDVKMKNTS. 2G5 It is evident tliat folds like those iiiiist have tali< ii ithiee In ((nn l)arativel\ recent time, and lonj;' alter the eNisteiice of tin' Mammoth Mountains, which ha\e been so deeply carved into peaiis liv erosion. The fact that the folds described alonj;- the \ nkoii ari' situated at the foot of the .Mammoth ran.ue su;;i;ests that liiey nia\ he due to the weijiht of these mountains, which has crumpled the lower beds where they have been stripped by the erosion of the river, and so ar<' capa- ble of beiuf^c easily bent; and a similar ex))laiiatioii may perhaps hold ;;(iod for other occurrences. The vast alterations in the attitude of strata of so j;reat thickness and weight and the ineipialities of balance jiroduccd by the profound erosion of Tertiary tinu' < an ihit I'ail to brinj;' about in phu'cs minor movements which tend to rotoic, however sliylitly. the ei|uilibrium. PLEISTOCENE MOVEMENTS. SUinrEHCI'.NOl',. .\i various points in Alaska terraces or rocliciit bein-hes are touinl up to meat hei.uhts and in such jiositious that they can be explaiiu'd (uily by the supposition that they are nuirine shoreliiu's. These are olten obscured by erosion, ami yet are ;;enerally so wi'U marked that it is clear they were fornu'd at no very ain'ient i)erioii feet above lh(> river, while at hm to liuii feet is a level- topjied plateau (see J'l.XX.Wl. p. Jul'), i'he lop of this plateau iscovered with rolled ;;ravels(h'rived from \aiious sources, often indi- (•a(iu;;by their natiin nsiderable traus])oi'tatirraccd appearance up to the sk.\- line, ri. \1, is a j)hotoiira|)h taken alonir tlie Yukon in the vicinity of the' Kay U'iver. anil shows the terracing;' rather iiulist iiietlx . After passin;; the uM)Uth ranii'e ha\e bohl. sharp outlines, the li'ieatei' part beinn (lislinclly. thoiiuh ofti^n rudely. Ierrace>( l.'iiinoi- L'.diiii l"(M'l on ,'i iiiiiiihc'i' of llic iiioniilaiiis iicai' tin- ^'llkoll hclow Xulalo." Il is not ccrlaiii ulictlicr Ili(' scarps nolcil liy i'rol'osor 1 JiiNScll arc I lie same as I liosc aliovc dcscrilicd. 7 I'ri'dci s 1)1 I /.s7<(//f/.s- /// //)' sill. — Diirini;' a slav of a I'ew ila\s al liarliorol' lliiiliiik, in llic islainl of I'lialaska, llic iiiouiilaiiis risiiii;- |ircci|iitoiisly alio\c the post were as<'ciiile(l. 'I'liesc inomitaiiis arc (■oiii]ioseil alliiosi eillirely of iiiiieoiis rocks, soiiict iliics massive, liiil irciierally porpliyrilic, wliicli licloii;;' cliictly lo llic iliorilc-aMilc--ilc family. .Vll lliesc rocks areallcred ami have mil 'he appearance of \-er\' rcccnl oi'ii^in. \Vc mnsi pass oxei' fiirlher ilcscriplioii of the ruck {feolojjjy. ami eiinliiic oiirschcs lo llie lopourapli.\', wliii'h has direct bearini;' on llic (|iicstioii nmlcr ilisciission. The island at tills point has a vi'vy Irrcunlar ciiast line, lieiiiij; Invaded liy sharp, narrow liords. In the inlerior llic lopourapliy is roimli ami varied to a reniarkalile deyrec, the peaks lieiiii. liar[) and the ilrainau'c system so Imiierl'ecily dcvelo|)ed ihat the sceneiy possesses a peculiar wildness which is rarely seen even in moiinlain- ous districts. The trip from the liarbor was made southward alony' ihc sliorc of (aplaiiis liax' pas! llic fool of the iiionnlain set down on ihcCoasi Siirx'cv Chan '.111117 ms I'\raiiiiil .Monnlain 1' ■I'hen lurniiii;' lo Ihc left, wc ascended Ihc luoiinlalns and allained tlio ridne contlnnons wilh hnl to the east of Pyramid .Monnlain I'cak. To 1 he soul h of I his ridu'i' ami l envere'i In a liei-lii <>( aliiillt l',Olill I'l'et with tllieU limss. wllieli linhls liinislure like a sjinULie and eniilinnniisly jeeils the in nnimTalile rills uliieh start e\eryuliere from the imiMlilain tops. All t liese litt le rills likewise deseeiel IHmii one terraee to another, so that falls are very nmiieroiis. while mi llie llat surfaces tliewatei's form ititrii-ate meaielers. marshes, or prel ly ]ioii(ls. These rock lieiiehes eaii he nothiti.ii' liiit sea elilVs. ami till' small ainoniit of erosimi whieh the streams ha\c arenmplished shnw a comparatively receiii ele\ation of 1." feel or so. The ele\ at ioii llllisl have been iiitermittent. since the .-ca remained Ioiil;' enniiLili al I'acli level to car\e a (dilV. and the'ii receded .so rapidlx that il in 1- plishcd little erosion. The dee]ily cut heiichcs are alioiil half a do/.en in uumlier. showinu' tin' same niimlier of snccessi\i. uplifts, which a\'era.iicd Jnii or..'li"i feel each. in this eoiineelion it may he noteil that cm the riuhi side of ( ap- taiiis r.ay a waterfall is seen deseendin^ the perpendicular lai f the rliff into the .sea. and this fall is said to he 1 1'd feet liiiili. < »n the shore near the \ iUa.iic of iliiiliuk man\ shells were loiiml in nooks of the ro(d< al idevalioiis which would seciii to he several feet aliove the reach of the hiniiest waves. These were ipiite fresh aii ojijiort unity was haaiiii' li>|>i)L;i'a|iliir |)i'c',iliai'il ii's. < Till' iiliriHiiiiciia which haxi' hccii (loscrilifd riuiii llic islainls iii ■liim >>''a arc niily I hose vv liicli show il vcr\' jii'cat siihincr^'ciicc in lhcsc evidences will hi' coiisideicd coni|iai"iti\i'ly leceiil lime. Al all 1 hese localil ies, and at a niMiilier of oilier-, there isalnindani e\-ideiice of elevation in e\i i-eniel.\- recent, and |ii'olialil.\' in |ii'i'sent time, am later. I'l i-i-iiri s (III llii I'l'i"!' Viihiiii mill )f iijhhiiriiKj n ijiitiis nf Uri/ish Cnliiiiihiii. It has alrcad.x liecn noted thai the dee]), well-marked valley of the rpiii'r \nkon is dislinctly lerraced up to a \eiy ureal hei.uhl. l'r()l'<'ssor' Unsscll' dctermineil a terrace near the interna- lional lioiinilary on the Yukon to be 7:il feet above the river. .Mr. I!. I i. .Mc( onnell ' notes that on the ^■nkoll ii short distance hehiw the mill of the I 'llv rolled uravel.s evidentlv deri\-ed from liroken- dow n teiraces. were found in some alnindaiice up to a lieiuhl of siiii fiet. .Ml aloii.u the N'likon \alley Icri'aces are abundaiil. Ihe lower ones beini;- of ,iira\el. while those at a \ervhii;h elevation are less •rfeci in form ami lia\ e the a ppeara nee of lieiiii' rock cut. ( )n l,al i.iiKleman. as alreaily noteil. is a well-niarke(l jiravcl terrace al a hi'iyht of abiiiil ."ill I'cet above the present water le\el. whileabo\e this iii'avel terrace is a broad, well-imirke«l bench which appears lo be cut in I he solid rock. Dr. (J. M. I lawsoii' has noted well-marked terraces al many poiins in the drainaue of ihe I pper Viikoii iind in the in'i;ihboriii,i; re.uioii of liiii ish (oliinibia. lie tinds that the liiLthesl have an avei'aji'e eleva- I loll aiioiit '.III feel, while the\ha\e been found between ."i.noii and l.iiii" feel in a niimlier ot widely separated localities, thou,<,'h the principal deNclopmcnt is below :!.siiii or :i.."iini feet, lie remarks: Hflow a lici,i;ht of aliniit :'.,ililii feet tlic wliole liiti'rior PlaU'iiu ri'i;i(iii niiiy lie (Ipsrrilied as tcrraoiil. anil iiltlioui^h along the various river valleys iiiiiny lerraies occur whiili liavcevidt'iitl.v bwu jirodnccrl liy the streams themselves wliili'inrtiii]L; down throuKli the drift deposits wliicli at an earlier stage had tilled these valleys, these need not tie eousidered lii-ri', the 'wiiut to which it is wished to draw atieii- tioii lii'ing the existence of terraces reiiniring tor their explanation a general Hood- ing of the country. Such terraces are found to he not cotilined to the inmiediati' valleys of the rivers, Imt to o;'eur in ditterent situations along the higher .-'oiie<. anil to friuLTe at similar elevations the various irri'gnlarities of the plateaus. y. rrnri .s i,)i /III I'liiriiiiiiii . — .Mr. K. (}. .Mct'onnell^ has noted on the mounlains between the .MackL-iizie and the Porcupine draii ' Op. .it . |>. Ill .Mill, Ui'pt. lii'.il. Xat. Hist. Survoy ("iiiindii, Vut. IV. Isss-.sii, ji. :.ND. 'Ti-ai.s. Huval . raimilu, V..1. VIII. . pp :i, It t I FH SI'I-IIK.1 PLKt: ''DCKNE Mi >Vl:MK.\T!*. 2i;!i tc'lljic'fs ill nil elevation (if l.."iilll iVel and linile ahoN e tlie sea. "Ilile aldllLTllie Upliel' ])ai't of tlie I'olcilpi lie l{aill|ia rt s eoal>>e niav el-» Were noleil ill \ arioiis |ioiiils ii|i |o ele\ at ion^ of Imi or 'hhi iVci aliovcijie sili'faee of I he ri\er. Siiliiiii riji iici Inil iriili il III/ /(/■/•<((•( .v.- 'I'lie^e |ilielioiiii'lia imii lie explaineil only iiy tlie siii)|iosilioii that in eoiiiparatix cly reeent limes the sea stood at a lliueli irreater elevation Iliail at |ire>eiit. (>\,-\- Ihe urealei' |iarl of eastern Alaska and adjaeeiit pails of llriiisli ( oinm- l)ia t he feet above the river, and on t he ^ppcl■^■||koll iIh^v have been noted as much as Slid feet above t hi' river. I )r. (i. M. Dawson ' notes that Ihe summit ot' an isolated moimiain on ihe vvalcrslicd between the I, lard and the ^■ukllll river svslcm^. at ;i licii;hl of l.:loo feel above Ihe sea. was found to be slrewn uilh rolled sloiies of diverse iiri.uili. such as to show that walcr must have stood at one lime about l.i«"> feet above this part of 1 lie racilie-.Vi'cl ie walershed. I'l r'niil III' ill iHi sNidii .Vlthou.uii ofleii millilated by receiil erosion, the liii,di terraces which have been described conform in i;eneral willi the present topoi.iraphv. follow ini:- all the, ureal irrei,Milarii ics, such as the nioiintains and t he lariicr valleys. The diep valleys, as before noted, were probably eroded chiellv in I'lioceiie time, since ihcv cut strata which have been rererred to the .Miocene, while thev are older than the period at which the cordillerali .i;lacier e.xisled. The sub- sidence of the land, therefore, which enabled the sea to carve terraces onlhe faces of I liese valleys, must havetakeii placeinlate j'lioceiieor early i'leistocene time, 'i'his is in accoi'danee with the coneliisionsof Dr. <;. .M. Dawson.- which vvei-e derived fiom a st inly of the lilacial phenomena in the drainage basin of the Cpper Yukon and in tiie adjacent parts of llrit isli (oluiiibia. Dr. Dawson supposes that eer- ■ Trails I!..viil .s..c (1111:111:1. V.il. VIII. >f'. I. p. ^l'^. ■-(Ill . ■it,. 11 I-'. • i I •_'70 (ir.()i.(i(;v or tiik vl'kon odM) distkh t. alasica. tain trlficiiil n at Minii-wlial miit'diiii li'\cls hclNM'cii l',."iIhi iiihI :;,iiiiii iVcI aliiixr llif N"'a. wcri' (li'|iiisilr(l in lln- sea wliicli at ihal lime wasln-cl the icliTatinu' IVnni nl tlir uiai-iiM'. .\lisi iii-i III' i/hii-ioliiiii mill riirl: i/< iyii> nl' rruinnal ,uiaclalii)n. 'I'lic iiori li- ciii limit 111' ll uniilrv (ivit uliirli llic curdillcran ulacicf miummI is clcailv (IcIiniMl. ami lia-- lirrn I'ccumii/cil by cmtv u:('ul()u:isl \\\\u lias liaxi'li'il ihi'iinuli iliis I'liunlrv. 'I'lir line iiiaikini: 1 liis limit may lu' liiavvn t'lom llir l.cwi's. al a iminl lu'lnw llir jiii; Salmmi liiMT. IuIIh' While lii\>( snhmiTiii'iicr. wliii-ji liavr lici'ii ilrilniM'il as piolialily I'xisiini: al a iMiiM|paial i\ I'ly iccimi' timi'. run- li'iii|Miram'ons in a i:'('ni'i'al nay uiili ilu' maximiiiii i^iacial inn. 'rii<> I'ai-l 111' snlmicriii'iicf I'Xiilaiiis ilii' alisriicc ul' \^•(^ aclimi. anil llii' saiiii' icics wliii'ii i\(mI icrrai'cs or inarinc slmri'-lin cnisiM' aui'i mn.>l iH'i'i'ssarily lia\<' swept away aeeiiiiiiilaliuns ut' ileeayed rock. 'I'lie proeess ol' ruck decay is \ery slow a.s compared with tlic processes (if disinlcirral Ion and erosion in laN'oraliic |ilaces: ami llie amount ol' siicli decay which lias taken place in Ihe rocks all u\cr Ilie i,'laciatcd portion of North .Vmciica since the retreat of tiic ice is \cry sliulil. I'lolcssor h'lissell' explains I he alisence III' ileeayed rock ill .Vlaska as a lesiili of climalic conditions. I>iit in \ lew of llic considerations staled, ii si.-ciiis thai the conditions in Alaska will not fiirnisli any e\ii|cnce on liie ipiestlon of rock ilecay as a climatic function, since tile ihickness of roitcii rock swept away lp.\ inarinc action may iiavc liccii coiisideral)l(\ I;K< KNT KLi:\.\rinN. 'I'iiat 1 lie land could not iiavc remained loiii;' suhmer;rcd In tlic extent Just ilescrihcd is siiow n by tiic coiiiparat i\ c pain-ily of tlie records which litis submergence iias left. Certainly t he depression was mil loiiU' eiioui;li III permil the ;icciiiiiulat ion of sediments of any ;;rcat ihickness jilonu' the siiorcs of the sea. for the only deposits that can be I'cferreil to inarinc act ion at this epocii arc t lie rolled urax'cls. w hicli occur cxcrywiiere ami at urcat iicinliis. The land, therefore, after liaviliii liecii rather rapidly deprcsscil, wasauaiii as r.-ipidly elevated lo the position in wiiicii it is to-da\'. 'I'iie extent of tlic recent cicxation is determined by the same meas- urements as those wliicil lia\e been used tosliow llie pre\ ions depres- sion, nainely, tiie lieii,dits of tlie imii'ine terraces above the present sea level. Ill oiic case the scarps car\cd at equal levels on a land I Xiiti'scii till' r.iirlaii' (.'■■"lufiy III Aluskii.- Hull. Ucnl. .s,,.-. .\iij,Ti.:i. Vol. 1, p. l:il. ''{ 1 t Kl'l nil. I I'Li;i>r(K INK MmVI.MI.NI- 271 Mil rncc. ('uiii|«ist'(l (if \iirifil liilK, iiiiiiiiil.iin^. :iiiil \allt>vs. >.liii\v llml mI'Ii'I' llii' I'lirin.'ilioii ni' t his htinl Mirr.-iiM'. diH' in ;: Ioiil: |M'i'i\n\[. 1 lie rt'^jiiiii "Ms slink lii'iir.ii li I 111' sill ; u liili' ill I 111' iillii'c insliiiifc I 111- licijrill 111 wllii'll llli'sf li'lTili'i's lliiu siMllil ;iliii\ !• i lie |iri'si'iil M'.i |r\rl Irslilics 111 III!' r\1flll 111' llli' s||lisci|llf|ll i'lr\ ill inn , ImiIi'ImI, in Ihc liillcr ciisi' llic I'l'ilci-ioii iiM'il i-. lairly aiTiirali'. Inil in llic rnniiiT mil iH'ccssai'il.N SI), siiK'i' We can mil sal'rlx assiiiiir i lial tin- I'lcv ai imi 111' ilii'lainl prrviiiiis In I lie lii'iircssinii was i lif sanii' as il is in-ila.v, anil I hi'i'i'l'iiri' tlii' |iri'si>iit hriulil nl' llii' inariiii- IrrraiTs alin\i' llir SI a is 111' ilsi'll' nil \ rl'\ arrnrair i-rilrrinii 111' I lir aim HI 11 1 111' •|i'|ilrssiii||. Asa iiirans nl' iiinrr I'ldsclv asi'i'i-lalninu' llif I'Mnii nf lliis ili'|iri's- sinii. Ilir ili'r|i rixcr salli'vs, wliii'li wi'i rmji'il in I lii' iinini'iiiali'ly |ii-i'i'riliiii; |nTiiiil. ina,\ lii' laki'ii inin ari'iiiini, siiii'f ilii'\ may si'ivc 111 ilrli'rniini' aii|irii\iinalrly llir |insiliiin nl' ilir ain'ii'iil sjinir liiir. KVIIiKM l.s nj- UKl KNT i:l.K\Mln\ l\ llli: I STl.l:l' HI. I'.i'siiirs tlic Ici'rai'i's. ill llli' inlcrinr nl' Alaska llifri' arc in lie rniiinl III liiT i'\ lilcnrcs nf i'nni|iai-al ivi'l.v n'rciil clcvalinn in llii' ilciinsiis in ri\ IT \ alleys siii'li as ilia I nl' I lii' ^■|lknn. < >n lliis i-i\ it ami ils i rilni- laiii's ail' thick ilcpnsils uf sill, which were c\ iilciilly laiil ilnwn in ijuicl walcrs. 'I'licsc sills ha\c already liccii ijcscrilicij I'lnin nianx |ilaccs, ami the area nf their ffrealesl exteiii is iirnlialily the ^■|lknn l''lals. uhel-e llie\cn\er all area 111' alinllt l.'i.iillli si|liaic miles. All Ihescsill ilepiisits liaxe lieeli cut llirniiyh liy I he |iresenl ri\ el's, which havcalimisi always a rapi.! cnri-cnt, iiiit'a\ nrable In I he ilepnsit ion nl' i'.nc material. .Viinxe Lake l.cliarnc. mi the N'liknn. I he sill hliilVsare as much as l.Mi feel lii.uh, ami al the I'alisailcs, mi the l.nuei ^■||klln ai'calinul I he same lieiejit . while at .Myi k Creek t hey are .Inn |'i'|.i nr llinre al)n\e Hie river. -M lllese two last- liailieil liica lilies I here are fiinml ill the silts niiinci'niis frcsli-waler shells, all lielnnuiiiL;- In lixiiii; specirs, .Mnli;.;- pnl'tiiilis i>\' the rivers, where the silts llli lint ncelir. there are. np In ciiiisideralile heiulits. aliimst emit iniimis i^rax el ter- races ihriiiiiih wliicli the streams have cut. It seems prnlialile t hat the liraxels are ihiived frnm detrilus with which the deep \alle>s were jiartially tilled at the time <>\' the siilniier,u;enee: while the | ul- iarities nf the lirnad. deep silt depnsils indleale liial they were furmed ill niimermis lai',i;c. shallow lakes siiliseqiieiit to tin einerueiiee nf Hie land frmii the sea. Init he fore il had attained ils present elevation. 'I'liese lakes were drained ill cnlisei|llem'e nf flll'tlier Uplifting, aeemii- lianled liy sliiriit lilliiii;-. which aceeleraled the drainayc. so tiiai lakes and slii,ueisli streams lieeame transformed into rapid rivers. 'I'lie record of this sudden chaiiue is found, ainmi^- other places, in the thin laverof river uravels wliicli lie on top of the hiiili silt ItliilTs on I he I.ewe.s and other streams, Tlicse ji'iavels. contrasted with the iimler- lyiiii;' silts, show a sudden inerease in the velocity ol the water, while the thinness of the uravels shows that llie stream, in ciiiisei|iii'iice of m '■iir ,t ■i 212 (ii;iii,ii,,s til' Tin; vi kun cold lusrwii t, ai.aska. il> illl'ICilMMl \rliicil\. I'!l|liriliiiaril,\' t'niiii JiMo ."in t'l-i'ti aliHNC the sea, cNccpl in lour or li\(' plarcs uhi'ir llnir appear iini- lienet'S, uhirli oil exailliliat ion are rollllil to lie aiieiellt \'ii|eanii' crators. 'I'lie material ol' tliese emineiiees is ulivinu-hasall, ami small (lows of the same material are exposeil in plaees aloiij,' (he shore. Iiul the main part, of the islam! is eninposeil of walerlaid ■\oleaiiie ash, leslinu' in plai'es u|m)1i a lieil of chiN coiitainin;.; ill-assorieil pelililes of various sizes, which slronyiy sii;r;;esls lee i.etion. In the walerlaiil ash are liow lilers of roeks foii.'iun lo the islaml, which are larire ami snliaiiiiiilar in shape ami lie in such a inaniier as to imlieate t hat t hey iiave lieeii droppetl from sonu,' ic(> eake. ]n the ash are I'oiiml sticks ami holies wliieh ap[)eai' (plile fresh. A .short (li.stanee from the post at .'st. .Michael is a small islet know n as Whale Island, which is separated from St. .'Michael hy a shallow strait much ulist riicteil hy lar.i;e rock frauinents, as iiiay he seen on Coast Survey chart \i>. '.i:>7."i and in I'l. .\I,I. Tlirouuh ihissirail the tidal currents are notii'cahly st ronjr and coiit iniially niidercui t he hliill's. On the SI. .Michael side of the strait that pari of the hliill' which reaches (lilt toward \Vliale Island and seems to he a at a time wlicii the island was holow the |»i-i'S(Mit li'xcl. a id this ninciit niiist at I iiiii'sliavc carried iee in lai'u;i' aiiKuinl. wliicli, ^riiidiiii;- aloiii: I lie sliofes, pfodlleeil the moraine w]ii<'1i lias lieeu de^ei'il led . I See IM. XI.II. p. -'71. ) Tile 1opoe-rapli\ o|- tlie i>laiid is. as a rule. \ei'\ sliulilly dilVereii- liateil, and shows all the niai'ks of ocean cin'i'eiit >— -liroail chaniieK with the low banks wliicli ci-oss iiari'ow parts ot' 1 he i-l.-iiid. and uhich wore once e\idciitly straits: basins made b\ soiin' edd,\ in I he marine ctirrciits, and other mark's ol' a shallow sea bottom. .Uoii^- the --liore-- of the island, moreover, are r;iised be.-ii'hes at x.'iriou-. lieii;lits abo\c the water, and on the most recent of these there is e\ idence that an (dcNill ion is now uoinu' on, since lines of i;ra\ els h;'\i' been thrown iqi which arc a|i|)ai'enlly beyonil the reaidi of thehii;hesi wa\e>. .\ccoi'd- ini; to a t railer at St . Michael, t he old men amouL;' the n.it i\ e l-'.>kimo say that the island is now risini;' and is hii;hei' than wln-n llicy uere y on 111;', and it is widl known amoiiL;' the nal i\ cs t hat pile-, ot drift w 1 may be foniid at points when' there is now no water, the >ea haxiiii;' I'cceilcd foi' considerable distances over nearly level Hats. / '//(//(/.s7,r/. — 'i'lie hiti'licr terrace-, on tlii' island of Inala-k.-i ha\i> already been describeil, and the lowest oiie>. which are now close lo tile sea and are so recent as to be |)erfect. will now l|i noted. .\bo\ !• t he bc.-ich at t he port of Hi ill ink t here i-- a well uiarked >carp whi(di was el idcntlv" rci'cnlly a bi'ach line, and yet Ixdow the t'oot of this sc.irpfora iiiiiiiber of fei^t th.e lev el Mirt'ace i-. heavily covered with arass ami ap|iears nevei- io be i-caidied by the liiL;li<'st waters. .\bovi' this scarp comes another level, ^rass-covei'cil surface, which stretches back io i; third scarp, which, howevci-. is less regular in oiii- line. .Vbovi' this still other terraces may bi' distinct ly seen on the hillsides up to a ,i;r(-al heinlil, tlioiiuii oftt ii obsciiri'd by I'l nt erosion. The lowest lerr;iei', how ever, vv liicll has been melil iolled as beim;- clo^e to the bleach, conlnrnis 'cry nearly in outline lo the preseiii beach, except 1 hat il i-. 1 he arc ot' a smaller circle, (in the bro.id Mat top of the tirst iierfect terrace all the houses of the port ot' liiiiliiik are built. (S.e I'l. XMII. p. L'Tti.) I'lii/ii. (In I'liua Island. es| ially aronnd Si|naw llarlior. the rcei'iii icrracis are \er\' strongly marki'd, the lowest, which is only ab(Uit li feet aliove the present limit of liiuli waters, following;' all the curves of the present shore line. The' highest lei'rai-es are not so I oni imioiis. but an well marked at intervals. 0///I /■ /oe. /////< .v.- -The t'ollowiliu' I'Viilellccs ot' recent elevation of land in lierini;' Sea liave been iioIcmI by l)r. (>. M. Dawson:' (in St. ■ (ii'iilnni.'ut lilt.'-; ..11 s iii...t 111., i-.ia-t" .111.1 1-1:111.1.. ..f HiTiiii; s..ii mi. I m. luity lii'!. I i.'ol. S. !■. Anu'riiM. V. .1, V. i.s (ii.-.oi. I'T ;! — 1.^ It:- 5 ^^n ^ i['.%] s II -m i 4 b ill 4 -Jl \ (ii;i):.(i(iv oi' 'iiii', YfKON (ioi.n ihstrk t, ai.aska. r.iiil l>l;iiiir Idiiio nf walrus mimI whale arc rininii hi (•i>ii.->|ilrralil(> jiliiiinlain'i- (•iiilii'iiiicil III saiiil.v ili'iinsiis aliinil In reel al)ci\<' llic hiyli- <'sl lr\i'l III' iiiipilcni Niciriii wasli. (>ii St. Lawrence Island,' al alioiii Jill I led ali(i\c llie sea. Is a level plalcaii. wliicli may he an ancient plane 111' marine ileniiilalidii. ami wliieli has a fairly disiind terrace at an ele\ al imi nl' a I mi 1 1 ."in lee I almx e t he sea. Al 1 lie island nl' .\l ! II. the westernmost in I he .VIeiit ian idiain, ;ire .ilsn evidences of rcecni elcxaliiin. Dr. |)a\vs(in ■' says: .\'p'iul ( 'liichiiu'ei ll.irli'ir lh>'ri- iirc smm' wpll-iiiarkcd old sea rlilf- risiin; ln-liiiiil liravejly Hat- '.'II or :tii feet 111 li"iulit. ami sui-li us te iinlicaic an cicvaliuii nf the l.-iml liy lliiit iniioiiiit sine- their ' iriiiatidii. On the shijies of t'n' viilyr en the West side of the liaihor sevonil . lintly iiiiiire.ssed horizoiitiil lines also aiPiie,!!-. the highest lii'in,:; ahoU! :iiill feet ahove the sen. They seem to it'iireseiit iiiciiiiem tei-nit-es, anil if so, must iiidicare a soniewhiit rapiil elevation of the land, siieli ,is to prevent any hin,i;-i'ontiiiiied marine action a( any ii.'irticiilar level. \\ (ajic \'anciiii\ er ' a fairly distinct terrace was iihservcd al a ilci^illl III' Ml Id Inn feel aliiix c llie sea. On t he .Vsiat ie side iif the sea, (III the jieiiinsula id' Kanicliat Ua, ' a plane id' marine ileiiiidalion u.is Hilled at aliiiiit 7nn in sun feci almxe 1 he sea. '["Iicre is also evidence ol' imire recent elcvalinii ill that llie valleys which have heeii cut dipw n I hriiuuli Ihis upper plalean tcrminale at aliniil .".n or inn iVcl aliove the pres. ill sea level. Dr. \V, II. Dall"' Holes that ai I'oiiil Ihiirow a siial't siiiiU loai nth of oTl feel passe.l tliroiii;li siic.-essi\-c layers of innil. sand, and line jrravel, with fraunientsor drift w I and niarine slndls. The foriimtioii was clearly a lieacli alluvium, and so receiil that a pair of I'.skimo woiideii snow e-oufiiles with a siiieu striiiu' still attached to them was riiiind al a deplli of -27!. feel. roM-|.rsliiNs \s 1(1 Ki:i K.\|- |-.i.|-.\- \llci\. 'I'lie instances cited show thai imisl of .MasUa is al present risiiii:', and t liai this elc\ at ion has uom. on f,,,- .| imin- i inic Indeed the i ran- ,silion of the Nt'iy n lit sand lieaches and low sea cliiVs to succes- sively lii;jlier and liiuher ones, which Itecimie more and imire did'aeed liy enision, indicates that I he presenl iiiov einent is only a emit iniiat imi lii)ri'> 111' tlic (riiir (if Alaska arc iimn' 'li'iircsscii. Tlir ililTi-iciicr ill llii- i-liarat'lcr cif the coasl line isxcry iiiarUi'il. a- ^liuwiiou ilu' ( (PM^I Mn'\ cy t liarl III' Alaska ; cM'Ii Im'I wccii llic ikuIIiwoI ami mmiiIi- casi siili's ul' Alaska ri'iiiiisiila iIhtc is a ^timI ililVcicncr. Tiiis is siisi'c|il ihlc 111 cNiilanal inn. Iiy sii|)|)iisiiin- irrru:iilaril ii's in tin- pcisl- Miiii-cni' cli'X al ion or in ihc more i-itcmiI ii|)liri. 'i'lial Ilic n-iriit dc- \atinn.ai Icasi, has liccii sonu'wliai iiTi'iiular is shown li\ |ihysio Mi-aiihii- ■\i(li'ncc. In ciMiain pai'lsol' I hi' Tcriilory. iiortlmasl ami so:itliui'>l rixiTs likfllif I-owit Viikiiiirni aluavs ihrif imrlhwi'sl hanks, while in llii' saiin' iruions -iiranis likr Ihi' \'iikoii lirlwi'i'ii ( iirlf ( ily aiul till' roi'i'iijiiiii'. ami liiii'li ami lii'a\ I'l- iTi'i'ks. u liii'h llou ihniimh level Hats of sill ami niavel ami ai'e tlierefiiie iininllii- em-i'il in llieir chniee iil' direelioii liy roek sli'iielnie. Mow straiiiht ami iiarallel to one aiiol hei- aei'oss llie Niikmi T'lats in a noil hweslei'ly llileel ion. 'These |ieeiiliaril ies of ilraiiiai;!' {loint lo a ueiieral iiori h\\e>iei'ly till in 1 his re^'iiill. It is also possilile. eolisiilel'llli; the e\ iileliees of I'eeelll ele\alion nil the shores of lierini;' Sea. that llle estrenie liol't h wesleni jiait of .Vlaska has 1 n ii|ilil'leil sliiilitly nioie than the sunt heasleni |iafl. sii that the siii-Caee here has a sliiiht tilt soiitheast wanl. Imleed, it is iM'obahle that there may lie a series of liroail. senile wai'|iiiii;s nvcr the whole reiiioii. The axes of these war|iin,t;s may lie taken as approximately parallel lolhe.Maska I'eiiiiisula. « hose t wo sides show such ilill'ereliee in theuelleral eharaeler nl' theeoast li"e. Some slleli w arpiniis as these may ai iiiil for 1 he eonrse ol' I he Lower ^'llkllll. lielow its ureal heinl the ^■nkoll appears to lliiu ill no uell- marked. deep-eiil \alley, lull rallier lliriini;h an ii-reyular eonnlry, where it si i a,u,i;les throiiL:li Hals or pliinues thnniuh narrou uiii-j;es of 1111 U'reat lieiL;hi. This eharaeler is in st rmii;- eoiii rasi wiih the I'pper ^■||kon aliiive the I'lals. where the \alley is \ery deep, well marked, and pei'sisteii). .Mniii;' liie l.ower ^■ iikon, iiioreii\ er. t he hieation nl' tlle\alleys. with respeet In llie present drain; .:e. sllL:i;e-\-^ that the ri\ei' system may have been materially altered in roiiiparal i\ ely reeelil lime. Til is w as espeeia I I.V IH it ed ill llle Inwcr Kaillparts. It may lie. Ihel'efnre. that the Nllknii nriuiliallx Unwed strailillt nnrtli- wesl intii the .Vrelie ( »eean. and thai, in e(insei|llenee nf a uelieial siMldieasI till nf llle re;;ioil mil'thwest of il> pl'esellt InWer enlllse. it aliandnlied its aiieielll eliamiel and fniilld a wax snlllliwi-l to the sea aloiiji' the axis nf tilliiii;- Ihrou.uli the smaller \alleys n( its ow n Iriliii- laries and those of ol her si reams. "JT6 (iF.OLOfiV OK TIIK VrKoN (inl,l) DISTIiK'T. ALASKA. RIX'ENT \VARl'l\(i!S AS SlIOWX 15y DR MNAOE PKCl'LlAKITIEs, I'.y ll.\iioi.i. I!. ( iiiiinuK II. \i.\-K.\N iiiiAiNAi;i: As ll,l,^•^^liA•|'l■'.ll iiv imutvmh.i: iiu'kk. (Ii Id i-iil iiSjK ■■! nf ciiiiiil iiJ. — WHiXr l''(irlyillil(' (reck llic V.-llli'V of I lie ^' iikim is p'iicrall\' luiiTiiw , aiiro fnllor than on anyotlioi' si roam, ami sinoo ils ilrainauo liasiii shows rortaiii ]iooiiliart ios pari ioiilarly woll. it may lio takni as an oxainpio of .\laskan ilraiiia,i;o. .Vt lliomoiiijiof l-'oriymilo ( rrrk a llooil-plain . to .'! miles w iilo has lieeii formoil liy the eomliiiieil erosion ami ilopositioii of this river ami the ^' nkoii. In this plain, aliont •') miles soiitliwos' of I-'ortymilo post, slamis ;iii isolalod reiii- iianl of the iiplanil in the shape of a prominent ooiie. arisini;' ."lun f,.,.) alio\e the nonei'al lo\ol, from which l,ieutonaiii Schwatka. in Iss:!, oallotl the st roam llowinji' alonn' ils base 1 ho ( due 1 lill K'ixor. .\Imi\c ('olio Hill the \alley of Fortyniile hoeomos ;i oaiiyon. often with ]ier- pondieul.'ir olilVs, I honuh the u;oneral annle of slope is perhaps ."lO . The liranelios of the main stream low in V-shapeil unruos. wiih -i, iiioileraloly hiuh .i;i'ailioiit, ami linil oullel tliroiinh uato-liko hariiers fornieil by riiliies parallel to the strike of the rooks. When those Inanelios llow al ris^hl an.ulos to the strike i heir channels are narrow, their .urailients sloe]), ami their tributary ri\ niels lluw parallel to the strike. When the yonoral IremI uf the stream is ilian'onally across the sti'iki' of the seliist. the water altei'iiatoly Mows parallel willi the strike ami cuts across it at ritilit aiiiilos. Syminol rieal riil;;es are I'ornioil al the points of conlliionee of the main creek ami ils tributa- ries bylhe intorsoel ion of the slopes of iho V-shapeil \allo\s ( see li.U'. -II). The fall is eonsiilorabli — on the main crook nearly In feel to Iho mile. The oiirrent is thoi'oforo stronn'- from s lo lnmnes per hour — ami this, touotlier with the shape of Iho valleys ami their rim- iiodnoss, is evidonoo that Iho ilraina.uo is in its youth ami that the bod is now boiiia' doeponed. llii II III- II III mill (/, —There is. howo\or.an abnormality in the otlior- wi.se youthful-aii[ioariu,n- l-'ortxiiiilo Creek, for. consiilerinn the swifi- ¥^& K, \ il y ,,f PCI-- 'css, has aijj- .1 ail M,\,. u-iM IMII, liaiji ■■■■■ ^-1 1 "m ll: 1 si*-jMHI ^^ fl *\) ■'■ I'P^^I 1 ■ 1 // "msKsm i 1 ^, ■ ' ' - Ihr^^l^ ;.: '!'■ I V' '..: Sfi 1 ' ft i'" ' ^% ^,^^^H < » j^B^^^^^b'^I i P^W ^ ' Vl i Imp P| i' Still 1 t ■ . f' 1 '! Ml ii in w pf! ■I 11 .ii'"i.Ki. II ■ uKi i;nt \v.\1!:'1m;s as shown i;v iiiiAiN'\(;i'. I'TT lic>s 111' ils ciiiTi'iil ;iMil 1 he liariDWiioMir il s cliiiniicl. uc >li(iul(| i'\|icc't i(s riiiiyDii (MMirsc 1(1 111' Nliaiulil; mi iIh' cipmI r,ir> , il iiifainli'is anil fiiniis ii\l»>\vs likf a si I'l-aiii llnw iiii;' 1 lii(iiii;li an u|irii \ alli'V . I lif appai' fill iraMiii iH'iii'^' thai llic |ii'csciil \all('\' l'iillii\\>a liiii' ol' draiiia;;!' ]iri'\ iously (Ictcniiincil ; llial, in nlhcr wiinU. Ilir iiicainlciinir lialiil i> inlirrili'il troiii a lime wiii'ii llir slicani IIhuimI wiili |i.n> i;iaiii'. 'I'iic' oxliciws. wliicli arc li'cnci'ally rniiliiii'il lici \\ ecu ran,\ mi uails, all hiiiiy;li C'ri"i:iir. Alaska. sciiitli ilic yroiiml ii-i'> i;ciilly, iiml iH ;i poiiil J iiiili's I'lii-t licr m \\iil<'i' I'iiiiiri' III' vision i^' iililMJiicd. Willi ilic --ii iliiiii; oiil ni' iln' inpd^'- i'ii|p|i\' wliirli ii (listaiit. view all'iinls, il is seen ilial iln' I'lPiinirv al iliis clcvaliiiii is iiitl a triilv Ii'M'I plateau. Iml has lalln'i- ilii' asiicci n\' ,i liroail. shallow valii-v. cNlciKliiiii to Ihi'wcslas lar as III" eye can rcafh. Till' Incadlli nl' this i|c|iri'ssi(iii is a|i|irii\iiiialt'l\ s uijh.s, Iml il iiairous ami ur. iws shalhuMT lc)\v.ir( I In- p resent si i'imiii, ami iiidi it l'"( III >■ mile ami its t rilnilaries have elehed eaiiyuiis. while aliiivellie level rise liiw iiKiillilaiiis. w hose rounded oiillliies foini .1 ureal i-ontrasl In the hiy:lil,v aeeeiiliialed minor toponraphy. At many olher points the older \ alley was oltserved, notalil.v Irom Iheeiid of a ridu'e jnst above l''ianl decj<'a^e(| i,i width to J miles, l-'rom its ele\ at i' courses. .Vltlioiij;ii tiieir chaniuds iiaii not lieeii de,tri'iided lo l)asc-lev(d, liiere must si ill liave lieeii some fall, and the topo.ufapiiy. wiiile less pronoimced tluiii tlie present, was not vet featureless when elev at ion look place. 'I'lie streams ac(|iiired new activity by I lie lowerin.u: of their out lets and liciian the cuttinu' •■( Ihe present ttorii'cs. i>nt Ihe uplift was not rcvolut ionar.v. as is seen li.v tile fact that the streams now pursue the same ^'eneral courses which they held previously, the main drainaire lines at least not hein.ttallercd. lllVl.lts .\s .MKAsrUKS Ol- W.Utl'INo. I''or reasons alread.v .i^ivcii it is prohaiile thai llie ciitl iii.ii'of ihoe canyon \aileys was aeconiplisiied niaini.v in i'lioeeiie time, and that snliscipieiit to th(> cuttiu.ii' tiiere was a brief sul)iiiei'geiiee, followed by an elcvalioii uliicli is probably still in progress. .\s a result of this »,ii:' 44 • ;iii)-\VN r.Y iii;\iN\f;K 271) ■i;i !,•\^ I cli'V al idii till' (liiw n-( II Itiiii;' 111' th Mili'cllc \ ,ill<-\ -. w liirli iiilriTii|ili'il li\ iIh' >nliiiirrL;c'iiiv. has 'i.'fii i-cih'u .mI, TIlii ilirn' oscillat iiiii> were cxcryw lii'i'c llic saiin- in n-lal inn in iIh' sea li'\i'l is imiirdtialilc. I"'', in <-\i'\-\ iiiii\ nuriit nf mi i'iii'ii-...^ciiic iial mc i line a IT ii'iTiziilai'il irs. I lie icsiills 111' w liicli aii' m'c-ii in I ills, u ;n']iinL;s. ami niinnr rail scale Ihal 1 lic\ :iic mil ni'iicrallx \ isililc In llic nliscrv ri', c\ccpl liy cipin|iarisiiii nf d.ila c\l"iiilin,u ii\cv i-uiisidcralilc arcns, (crlain criteria can lie used I'di- (Iclerniiniiiii' iln' existence. aniMunt. ami ilirecliiin of such ilisi ui-'iaiiccs. Iml oli\ inusly these crilcria niusi he (Iill'erc!ll it. ililVerent pari s of 1 he llclil . ( )li Ihe i-oasl the fclatimi i if the iiplirieil slll'laee In I h ■ |nvscni le\el Liix es an o|i|p(irl nnii.\ rm- ill reel i|>Mrisiiii ; in |Miit ions i,i tin' Tcrritcir.x- remote I'nnii llie nceaii im -iich (i|iporl uiiil.x is iiilMrdeil. Here the delails iiiilst be I'niiiid l),\' a carcrnl exaiiiiiiatinii ,<( the inpdi;-- 1 hy a I'liiiipMrisDii of the previous cycle with ihal ol' the llei'led li\ a liltiillj: rai)li\' am "I presenl. for the drainaize upon a L;i\eii siirtace is a ariiiiiLi' of that siirlai 'hcret'ol'c I hi' I iiliaril i if the present drainai.''e .unc some hints as to tiie irregularities " I he nioxeiaeni imw actually in pro.ui-css. In those streams which are i'apidl.\ deepening i heir channels llie elVccl will mil lie soappareni as in I hose u hich uandi'r in open \ alleys near hasedevel; hut e\ cii ihe former may show evidences of tilt in the \alle.\ topo^raph.w l-'or instance, a competent stream u| a tilted sui-raee will perform ;^realer Work upon the lower side of the tilt than iliKiii the ujipcr. am 1 the resllll will lie c\ idelll in dilVerenl ways. Streams Ihiwin those Mow in.ucipiiosile to it are ret e- in the direclion of i|e lilt are acecleratcd ; ai'ded. and the result is the develop- ineiit of au'uiisymmetrical ilraina,i;-e system. !• iiitliermorc. streaihs which How al rii;hl au.uh's to ihe tilt will tend i > miur.iie to the \,<\\rv side of Ihe vallc.N . while tho.si' llowin.ualoiii;- i! pcrsisi in their ori-imil hat the svstem will he not only uiisymmet rical. hut the iiirse. so t trunk and minor streams will li.ivea rectanmnar iiiU'ra lerarraimi'menl. Those hranches whieii I'ow down the tilt will ha\e an advaiitaui otlier conditions Ih inn- Ihe same, ovcrthose llowinu' aua'nsi it. so iliai if uiiliiudered the former will divert llie latter in ad.iaccnt sysleiiis. Cases of recent or immiueiit siream caiiture an' therefore of -n-at \alue ill iracini;- irrciiiilarilies in a recent uplifi. 'I'lie ivsnlis of irre^:uhirit meiil of drainau'c a lies of ujilifl. then, are to he disi-ovi red hotll in the .iliLin- iid llie latest iopoi:raphie iirodiicts of erosion. Ill of the Vilkoii itself issii;iiiliealll. Till r"A'o//. -'riiealiu'iimeii character of its valley up to the pom Flats has lieell descriheil ahove. Here it eiilei- lit where It ell ters the ^■|lkoll iml, unhindered hy hanks of aii,\ coiisn the old taki' country l-rahle licielil. sliou~ a lelid- ilso docs ils nrdn IrihulaiN. liin h I leek, to swerve In ill riii'lil and lo outlet, as tlii' older maps had ii. i ilo Ihe Arctic 1 ici an. i i'l 1 m ] j il I 2S0 Gi;nl,()(iV ()|- IIIK YUKON (iOI.M DISTI.TCT, ALASKA. 'i'hri'i' iii;i\', imlcrd. liM\ c 1m ,1 \ <'i-y cnrlv ciMiisc in tlii>ilii liori \»liic-li riirlhi'i cApiiiral ion .-iliini;' tlic northern !il li;i\ <■ anlcdiili'il the inlcrlDr lal, lor llu- millcl ol' \\ii- lake jn'i'idil was, as imw . li> way ipf llie l.invcr Haiiiparls. 'riiis, licini;- llie lnwcsl ])(iini. iletciinincil till' (iii'ccl i(in in which Ihc ii\ci- llowccj al'lcr Ihr i-i'\i\ai of slrcani ai-ii\ il \ ami ilii' ilraina^i' of I he a nc it 'U I lakr. 'riironi^h llw l'.'pi* niih'-" of ilii' Vnkoii I'lais ihrwcik licini; ijoni' upon Ihcviulil oi-porihci'n bank is irn'a11\ in r\i'c-sof thai on the soul hi'iii. As an iiliisi ral ion of this il is said ihai no Itoainian nascvcr lloalcd down thi lower \'nkon mIoiil; I Iw h'I'l hank, for. I nisi i ilii' lo liic (Mirri'iil. Ihr hoal is invarialily drav.n loward ilic norilicin hank. When ihc \a ley is iiii'lo^nl hci ween raiKpai'is 1 lie icndiMicy low an I Ihc iiorl h is nol so nol iccahlc, hnl il has been ol)sc;\ci| by Dall and oihcis ihal Ihcriuhi bank is bciny' nioic \ 11;'! iron sly allai-ki'd all alonn' ihc fi\ crV conrsc l-'tirl iliiiih I 'ml:. The main fcal iircs of P'orlyiiiilc. inclndin.:;- Ihc older and more reccnl \alleys. hasc already bi'cn i|c>cribcil. I'or |iari> of il-. course Ihc older \ alley seems lo be di.-'ii., nl n|ion .'he yeolocical st riii-l lire. as. for insl:ince. fnnn I he N'lU'l h I'm-k lo 1 he inoiit h. w iicrc. in general. 1 he di reel i mi coiiu'ldcs w il h Ihc si rike of 1 he i-ocks. In ol her porl ions I he \ alley runs ai'i'oss I he i-o(d< si laicl urc. as bet ween Walker I'oik and \orlh I'ork. Tin' preseiH slreama'so. ils course beilii; direclly inhciilcd fnnn Ihc foi'nn'r. Hows in Ihc s.mih' li.isin al a lower le\id. showiuL;' no preference Uiv eilher side of lh<' \alley. bnt iHc.indcrini; bel ween t he moiinlaiiis. liisl iipmi mie side. I hen npcui I hi' (tiller. Scxcial larue slreams cnler from ihc norlh. the niosi im|iorlanl bciiiLiO'Uricn (reek, w lilch di\ides a few miles ,il)o\ c ils nnnil h inio Iwi) liranehcs. MowiiiL;- parallel with th main l^'iu'lymih', mie risinir to the west, Ih" other haviiii;' its source iindei' a hiuli i;ranilc peak known as '■ 'I'lic l)onn'."al ihi' east, 'riieic is a siiirui'sliun in this jjeeiiliarily of a dixersion of the east ami wi'sl heads of ( )"r>i'ien ('i'e(d< toward the stniih. There are also examples of probable divei'sioii in olher h)calilies. In all of which, howexer it must have oecnrred pre- vious to I he latesl uplifl. P'roni I he south side of l'"iu'lyinile I he I rilm- larics ari' miicli fewer and smaller than from the other, ''anyon and .steel creeks hcinv.' 'he larncsl ; ihe conlrasi, however, is probably due as much lo the .~nnill drainace area belweeii ihe main creek and W'.ilkcr l-'ork as lo any ol her cause. ,\b(Uii ."lo mile-. I'nun ils nioiilh. l*'orlyMulc divides inio Iwo main bram-hcs. 1 )f ihe Ndrlli T'ork lilllc is known, except thai il ha>!l- soiiri'c ncai' the headwaters of Itireh (reek and Mews in a nciieral direction eastward. 'I'll' Soiilli I'm'k. on Ihe other hand, has been Well pros] icil from ihe liasi.i-likc ari'a ai its heail to its jnnctiiui w i' h I he NiM'l li I'l'ik. so that its leal 11 res are much hel ler iimlcrslood. .Several small tributaries i iiii|iiirl,ini . Iicc,iu>c iliry arc till' i)nl\ ones upciii wliicli plai-cT iiiiiiiiiL; I is ih-im'cciIccI licyniid llir --la.uc 111' |ii'i)spcci iiiii'. arc l''fankliii (iiih'li and \a|iiilciiii CrccU. Ildlli of llicsc creeks sJMiw asyianielrv in I lieir \ alle\ s: ami in initli ai'e sleep side:- al \\\i- sonlh and a i 'e L;i'nl le rise inward ilie nnrlli. {•"ra:!kliii (iuleh is a strike \alie\. and ilie niiuiraiinn ••( ili- sireani liaxinu' lieen d.nwn ihe ili|i 111' Ihe roeks. llie siinlli side i^ a strike riduc "illi ii\erlianuin,i;' (dill's and |eiii:e- -a u'reat ennlra^l to Hie sinniitli. eas\ sUipes cif the iKM-tl' side. 'The npper and Iciwer parts (,|' till' valleys are wididy dilVerent. ,"''i'(in-li the lewer part I'rankliii (Inleh has enl a eaiivoii. lint m^arc^r I lie head the \alle\ lieennies hiiiadc'r. al an elesatimi eDrrespnndini; with that nl' the nld \alley npnn l-'orlyinile in this \ieinity. cil' whieli it rornied a part. 'I'liere is in tliis pdrticin, tun. a lelldeliey nl' the ereid< In Ihiw .ill the >.intli side 111' its \alle\ . Ill Nape il I ( leidi and many other irihiitariesdl' I'orty- lllil,. thi' -^iiaie lelldeney was iiliser\ed. as also apoll a few of the ei-eeks of the Sixty mile drainage, of whieli .Miller and t.laeier creeks, in I'iritish terrilory. may lie ipioted as examples. ( >n ihe latter two lliere is a \fvy evident asyiiimetr> of the \alley. the sleepesl side lieinii'llie soiilK. 1 In Davis and I'oker eiecdxs, whieli head in the Uald Hills nearly against .^Hller and (.laeier and iinile to piriii W.-ilk r |-',irk of l''orlymile. Ihe lemleliey. if il exists, is mil m.lieealile. Mi.ssKiii r,v' /.. -.Mission ('re(d< eiih'rsthi' ^■|lkon al a sharp elbow- heiid of Hie ialier alioiil .">o miles below JMirl y 111 i le and on the .same >ide of the river, .'i'liere is a wide stretch of linttolll here en the sollHl side of .Mission Creidv i iHi. liiil above this rise li ills the tops of which •ire at an (devatioii of ."iiin feet above llii' waler. apparenlly indiealini;- )i\ Hie evenness of their <'iesl line an ancieiil valley whieli extends l.a.d< for several miles into Hi- hiii'li nnnmlains. This is part of Hie -.1! e ,iearly levcd nplaiid remarki'd all through the rjipcr Kain|iarts, ',,i;e'!'- probably represcnls Hie old ^■llkon N'alley. !;• Mission ('i\-ek sysli'in is>lecidedly nnsymmel ileal, both in 1o[)ol;- 1-, phv and aliunnieiit. Vov the last jiarl of its iMini>e Mission ( ivek flows lliroiiuh a coiinlry which rises I o Hie s'' fr( iii the stream l)e(l 1,1 a heliihl of somelimes .Sim feel, fonniii^' a \ erilable wall wliiidi is l.r,.keii in Hie dislance traveled oiil.v b.\ diie small creek and a lew unllies. In oilier wor.ls. erosion is. in the main .'reid.;. piiH'C'din- more rapidly ii|ioii the iiortli. so llial the slream is .'row.!...! toward Hint side of the v;ille\ ; and the lira iiiaiic is reel aiiiiiilar ami sided. .MiN.'.ilers are fre.|iieiiH,\ sc-ii iijKiii Hi.' Lure tributaries. Wolf and American crc.dvs. as well as n Hie main cre.dv. They are, however, more prononneeil iipnn Hi.' lalier. .iiid yd, lhroiii:h all ii- waiiderin-. Mission Ireek holds its iMiiirse closi> to Hie iiorlh iiaiik. e 2^1' (ii;()i.(i(iv ipf riii: vikon um.n Disriiicr. ai.aska. ' ; 1 i '' ■< 1.' 1 1 :r :| M(/Niii,l,- (iii'l I liinh r ri-i I h's. - '\'\\r MyiKioU system iil' i| i-.iiii;i;:c. in llic l, oxbows, and here aaain is a remarkable fact. I'm' th(> eiil-olVs are formed only on the north side of Ihe valle.v : in no single case are th(\\- made at the south. Tlie universality of this t hroiiiilioul Ihe drainauie system is indication that tliere is generally an ace deration in the portion of the curves llowinii' mu'thward and a correspond iiiLr retardation of those llovvini>' toward the south. Tin urse of the creek is evidently beiny si raiahtcned by the cultiiii;' oil', but with I lie one-sidcdness of I he st rainhleiiini; action there follows a migra- tion of the vv hole creek tow an I t he north. (Sec Hi;'. -\.) Ilinli Cmk. — The topoaraph.v of iherenion ihrouah which lUrdi I'ri'ek Hows is diverse. The lower hundred miles is a ecuintrv oi' h ....i.Ki.M.l i;r.(K\l' WAKl'lM.S AS slldWN l;v DKAl \ \(;K. :.'s.". nil I'i'lirl. Il;il 111 111!' I'yi'- a MId-'-chv rri'il, I i iiilii'l'i'il |iliiili. III vvliii'll s\Viiiii|is mill lakes an' nl' i'iiiiimhui nciMirnMii-i'. '\'\\\-~ i- kimwn a-> llii' Niik.iii l''lals. ill wliicli Ilic ^■|lk(lll ami its t i-itiiilaiv. liiicli < in^k. tliiw parallt'l in iliri'rl imi ami arc sr|iai'aliMl li\ niily a fru niilc'- mT swamp. Kisilii;' In a iiiMLjIil nf -"ii"' I'rd almvc lln' slri'aiii-. ali'l I'miiii- iii;;' an i'srar[niicn' :l nr I inilrs scnil liui-sl dI' ( irrli' ( ii \ , is i lir -..■ihk. i'l.'\ali'il plali'an imii'il in ilir uIIht ilisi rii-ls, a iinrt iiu ai'l -|iiir ni' w liirli is rrusscil liy I In' 1 rail In I lii' i^'nlil ilit:':;ini;s, A Her .1 ,iiiiiini-,\ nf 1") mill's I'riim ( irelr ( ily almin' the I iiiiliereil Inp nl' lliepialeaii Mie I ravelcr eiinies hy a smlilell ilescenl In liireli (reek. A( this piiinl, where 'rwelvemile Caehe (a mail hniise I'm- miners) has heen eslalilislieil. the creek riilis lhriiiii;li a i:ap. whose liiMinilim;- siilcs, less than - miles apart, rise in sleep \\alls Inn leel ImliIi. I'n ihusiiiilh nC ihci^ap the \alley .iLiaiii spreails mil inin an apparcnily iffi (if ! m^ilkmWWi II ''"iim0'-'^ l-'ll, -.'I N.ll-tll-ill.- .■lll-'ilV illnl .l.-.TIr.i ]l|c illMl.'l- "H lllinlrl- C 't k lexi'l sirelcli n\cr 4iiii sipiarc miles in area, in these liireh ( reek Mats the creek meamlers in the iiinsl iiitrieale manner; nvlinws are ri-eipieiil. ami lliere are several examples III' I'nrnicr uamleriii.us in tin' nccurrenee nf crescent -sliapeil la,i;nniis wliich at im very ancient dale rnrmeil parts nf the meamlerinu' si ream eniirse. lint have since been cut nlVanil remain as lakelets. These are especially iierniis in tho vicinity nf ■i'welvemih' Cacli. . ■i'iiere is still anmiier kimi nf lakes, e-cncfallx larger than llie la;;oniis, wini.se nnHine is mnre nearly eircii- rarami wliusc iariic area shows liial they <'an iml l>e accnmiteil for in the same wax. ' >f ihese .Mcilicine l.,-iki' is an example, ami it seem, either that lin'\ ha\e been can.^eil hy a verv recent ilammiiiL;- <>t' tiieii- nutlets nr that they arcreinuan's nf lar-er exiianses nf walcr uliich fnrnierh' ncclipicil I he area. Kviilencc has alrcail.v heen uiM'ii m slmu thai the \ iikmi i'lals cnuutrv was at mie tiim upid hy a lake it seems alsn. Inmi ihe " "Sill S' m i, M ■'is 1 Hi iJHli I ant' I ' mi :.'84 (;i;oi.(i(iv of tiif, vinon gold uisiuicr, ai.a.ska. Hill Mil' nf I he ilc|ii)sits rmiiKl ill tlii' I Jircli (reck lljils. nliii'li ;iii' .iii>t siii-li ii> Wdiilil he laid iIdwii in qiiifl walcr, I li.-il llicrc was licrc alsd a lalvi' ii\ IT 1 1 II I s( I iiarr miles ill area, a IK I that in tlicsc sinalliT liiMlics df waliT «!■ Iia\ I' I hi- last siai^fs nf ilir ilraina.ii'c ami laxini;' liari' of iIk' liiiiluiii. Uy the ilrainiiiii- i>\' the lake M'l-tical ccirrasiipii was Im'^hh, liiii I he tci|ii)u;ra|)liic ri'siills nf I his icci'iil erosion dilVerin ilill'ei-eiit parts III' the lielil ami fail iiat iiially into three (livisions. In ihe lower, ihal ie|iresenteil li\ tl nt'et at 'rwelveniile C.-iehe. \erlieal from tlie iippci- division had I lieirael ixily inereased almost immediately, and Iteiiiinlhe higher t;uri;e cull inii' that is seen at the nioiilh of I'.oiilder Creek aiioiian/a, .Mn.er, llou'em, Boulder, Mi'slodon, and tlit' middle part of Itircli, ail of which, dis- I'c.aa I'd i n.n' ; Heir minor meanders, flow in a u'eiieral direction northward and acrc-is llie St rike of I he rocks. In the s(>cond class are the head of lii'di Creek, Xorlli I'ork of l!ir<-h. North and South forks of Harri- son, ami also ihe main Ka.ule Creek: these Mow in u'ciieral east and west, parallel to the strike of (he roII()\\N IIV 1 .1; \IN \(ii:. ■'X' Creek: amiin. I'lirlllel- In llle ea>t. IliiL;'e|ll (reek i» luWerillL: Ilie divide l)el vveeii itself and 1 lie Ncii-lii i''iirk of I larrikin, ami will in 1 iuie. if iniinlerrupled. sneeeed in leadinir nil' ils \va1ei'> liy a nearer idule ti) ( riMiked ( 'reek. In Ilie (i|)|i' tn the nerih. an I the minor liramdies. (^Miarl/. and .Mlierl ereidvs. which, risiir^ in I he Cra/.y Mminiains. eiiler iiireh (reck al rii;hl anuh'-. In i hcse yoiniii'er streams, owini;' pcrhajis lu the shalhiuiiess nf ilie \allcy- whleh theyha\(' cut . mi select i\c tendciic\ df I he si ii-an; channel is observed. However, in olhei- valleVs of ihe ( rnokiul (reek drainage a decided leiideney low ard the iKM-thci'ii hank wa--eeii. In I'lireii- pinc (reck vallc.v. for :l miles from its mcinlh, iIm- -irciin icniains closely under steep liliitl's at tile north side, Icavin^ia hroadly slnpinLT valley at the south. In tiu' saiiievvav. in the last :i miles of .Miller Crcidv. a terra f I"' lo i^'i feet is ohscrved. sloping:' ,L;radiiall.v in the ridu'c al the s(nithwesl, while upon the lefi bank ;he slope lo the creek is abrupt, with frci|nent binl'l-, (Mi these iwocreeks and on .Mastodon, whei'c the Icndcney is iioi so well shown, ilic a-vmmclry iscaused liya migration of lliecre M-i;- ol \>v\iMi;i i!V Ml ■,ini,.\.vi--. We have. then. lhrou,i:li ihi' interiiu' of .Vlaska, a rev ivi'd draiiia.tro sliovviii.u' certain peculiai'it ies indiici'd in the lU'csciil cycle w liicli are not conliiii'il to one erecd< or system, lint arc> to be found in I'mdi and evcr.v (Hie of the systems, 'l'hes<' are a ccrlain delinite ali.iiiimcn: and an unsymmctrical topo.iirajili.v, and their e\iei;siv •ciirience seems to demand for explanation some cause operative alike over lii-cat areas. We have already slated one i;eneral i-ausc of pi-culiarit ies in draiua,;:'!'. and by jipplyiui:- those ]naiiciples to the specilic cases. aNo bv a critical c>\aiiiiuat iiui of othci' possible causes, we may decide to what extent dilVereiitial uplift is rcsponsibh'. and whether in some eases it may noi be cut ircdy subsei'v ieul to oi her causes. TIk iirijitf ilitYi n iil'ml insdlnlinii. — ,M\ nook and ,Missiim cii'idvs atVord [lerhaps the best exampli's of unsyin metrical valloys. with their -teep noftlicrii walls, as described abov<'. Here by tlie alternation of freez- iiii;- and melting; icmperatures. I he ro(dis arc ln'okeii down ami the •J«i; (iK();,()t;v i»F Till: vumin (iDi.D i)i>ri;iir, Alaska. I i» iiiali'i'iiil is riifMi>liiMl 111 1 li(> si ri'Miii I'di' lriiiis|Mir1;il inn. IT I hen- is mix- '^[•i'ti\ (lilTcrci hciui'i'M t 111' .•niiipiiiil nl' licil ri'i-i'ivcd liy cil Ikt liaiili, the (iiic sii Ciivofccj will 111' liiiiki'M iliiw II iiKPi-i' rapidly, 'riicii. IT t lie sirt'ain is alrcadv (i\ ci'lnadcd. llu' uri'alcr siippl v rfoiii Ihc liiudily insn- lali'd haiilv uill ii'siill in \\\i- 'Tiiwdiir.: of llii' si ream away IVdiii llial siili'iil' llii' \alli'.\. ir. Iiiiw c>\ cr, IJH' si ream is a riiiii|)i'li'nl niic, Ihi' iiialrrial sii|)|ilicil will \>r hnnic awa\ , tln' iiaiik nf Lrn'alcr iiisulat ion will I'l'inain sli'i'|i. and I lie si icaiii will How close to il. 'riii' side of tjic \allc\ icc-i'ix iiiL,' llic most heal IVmii llic sun will lie the norlli, so llial tlic coiidil inn npon llic Iwocrc'cks naiiic. have their steepest sides t'aci lit; I lie iiorl 11. Jiisl 1 he opposite to wlial llie theory demands. 'I'hi nrii dl' Il ri'i si riiil rntiitinu. — .Another possible cause is ihai of terrestrial rotation. In Is.V.i Kernd I'ormiilalcd the law that all hori- /.oniallx' mo\ 'n,!^' liodiesin the northern liemi sphere are, I )y the rot a I ion ol' ll art 1 1 iiply b>' (i. \\. (iilbi'it.' '{"he latter came lo the coiiclnsion thai terrestrial rola'on is often a snilicieni cause for stream asymnieiry, and in a parlicniar case — ( hi' .Mississippi -lie calcnialed t hat the select ivc Icndciicy was '.i per ccni ureal er toward the riy:lit tliaii toward thelefi bank: bill he also proM'd thai only under peculiarly faxorabie conilit ions could llic cause 1 IVicienl. ■■.Vslrcaiii which rapidly corrades t lie but toni of its channel does not notably corrade its bank, and in such case the I'lTed of roiation should not be disio\ erable." The condilions of rapid \i'rlical corrasion here described apply lo a nia.iority of the streams I '' .Uaska. thai pari of the ^■||kon lyinu in the V'lats beinu almost the only water course in which vertical corrasion is subordi- nate to lateral; conscipicnt ly we shmild expcci icircstrial roiation nol lo bee\erywlicre of primary impoilance. If il were the priiici- |ial cause, wewiiiild alsocApcd similar results in regions similarly' sitiialed. but il will be reniembei ed that, while the einin iimelils of .Mission and .Mynook creeks are alike ami I heir \ alleys iiiisy innid rical. in the (Uic case. ^Mission ( 'reck. I he irrealer erosion has been upon t he norl hern or Icl'l bank in opposilion to I he ilelled l\'e force prodilci'il by rotation. .Mso no general asymmetry was observed in the north and siuilli How in.n' streams, althouuli by I'errers law all sircamsin the same lat i tilde should siifVi •• equal delledion toward the riuhl bank. Am, .luiiK S.M..:;,1 -..ri,.-. V..1 .X.XVII. 1^>I. r I.;;, S3 ' I ■». men. I l.'KCKNT \VAU1'1N(;S A> MHiWN \:\ DW MNAdl".. 2^1 Till I Ij'i rl III' i/i nil 11/ 11- si mil II ri . — Since ^l I'imhi^ :ni' iin^l:ilili' licidic-. I li ■} ail' iitl'cflcil iiliil lli('irali,t;iiiiic'iil i-. iimiliinMl ami nil en alliii'ii li,\' I iic iicoldi^ical siruci iiri" (if till' riicl<>. iiiid w liii-li I lii-v aici'diia'liuu: I lii'ir lic'ils. SoMii' ol' llicsc iiKiilitical iiiii> all' liiral. >iirli a^. Inr i'\ani|ili'. tile ilaiiis rrciiiii'iills I'liuml iipnii l^'urt \ iiiilf (rci'lv. ulini' a |iaiiii'ii- larly resist a nl la> er enisses 1 lie heil ul" tlie >l ream : iillier>. iIih' i<> i he atlilllile III' tile I'lieks. ale IlliU'e l'\lellN!\i' in ihrir elia rael el'. Ill ra^e t he roeks are hori/.iiiital. ami there are iiii III her ili-.l Milling iiilliii'iii'i'>. 1 he iiiir.ii'e of a yiiiinu' si ream will lie eiil Nerlieallv. lull wit li a ili|i I he (low ii-eiill iliiz ri'Mihes ilsi'ir iiilii Iwii eiiiii|i.im'ii!s ihr i me \ eil ira I. ami I he iitlier almii;' liiie> (if w i akiiess nlVei'eil in i'iii>iiiii liy [ilaiie^ nf schisliisily 111- si ral i Ileal inn. I'Ih' heil nl' . n' rrcrk, 1 llerel'nre. ilni's nut priieeeil ilireet ly iliiwnwanl. lilll llli.;iat<'s in the ilireet Ion nl I he ill) , anil the hank is eiil mure xiynrniisly nii that side, jirniliieiiiu' a (iiie-siileil \ alley. I' he aimiiinl nl' a ^y mm el ry i|e|ieiiils iipnii i In- allele nf lheili|i. W'il h hiiri/.iiiil.iiily il is n; at an am:le n|' |."i i hr ili'l'nrm- in:^' lemleiiey is urealest. ;,;iailually ileereasiiiL; until, when the rm-ks are xei'tieal. il is apiin i'. Ilnekskin. I'rankliii (iiileli. ami \a|inli'nn ereeks are exainples III' st reams wliieli llnw ill si like \ alle\ >. ami in all III' t hese t he ili|i is ral her sleep tnw an! the r.iiiltli. 'I'lie > alh \ ill oaeli ease is unsynimet rieal. with the slee|iesl siile at thesniilh. ai'nl t his wiinhl seem tn lia\e lieeii eaiiseil liy a niiiirai inn ilnwii the ilip, allhnil.uli, as w ill lie seen later, ntlii-; inlhieiiees may alsn enter. In .Missiiin anil llniiler ereeks the I'aels are ilillereiit. in eaeh the linl- niek has lieell I'lilileil Siithat, as nl'len as lint, the eieeks ern>s the strike and dip; the asymmetry nl' the xalleys. iherernre. is perfeetly independent nl' the ili]i. the stee])(>r hank heinu' always iipnu tin: iinri li lliroMjili all the \ ar.\ intr dips and st rikes. 'i'lie rneks of Hunter and Missimi ereeks lia\e mil mily heeii I'nlded hut are ai.sn faulted npini a small scale, which snt;i;'ests the idea that ma.jnr I'anlts lakini:' east and wesi enurses are respniisihle I'nr the enlirse nl' tile ereeks. and that the siiUlll-raeinil' wall ahn\e deserilied is a raiilt eseai'pmellt. ilnwexer. there i> nn cNidenee In sustain this Mtpposit ion. Till I ll'i rl III' liliimi. Il is seen. then, thai the .general causes nf terrestrial rnlalinii. insnlal Imi. and ,neii|nL;iral slriictnre. while appli- eahle in special cases, are insullicient to e.xplain all the nhservi'd plienoinena of one-sided ness. We are iihlii;i'i|, t here lore, to seek some oilier e.xplanalioii. and the only remaiiiiiii;' one is thai nl' an iiiiei|ual nplil'l, as sii.t;!,'esteil at the heiiinniii.L;'. \\\ il all phenoniena not explained under Ihe olher olles may he accounted I'll!'. in the Mission and .Myiiook systems of drainage, particularly, there is a retardation of tlie sonlliw ard-lhiw iiii; waters and an acceleration of 1 1 II ISC llowiii^i' north, whieli is seen not only in the hraiiches. eau-in.y: ineipialitiesof drain-iiic development, hut in all the meanders, 'i'iiis. il M IS. could have heeii iirodii 1 only liy a tilt of the surface silii- .jected to erosion, in this case toward 1 he norlli. T 'JHS (iKOl.ddV or TIIK YUKON COI.D DlsTliHT. ALASKA. n:, Mi. fWi 111 'I'liv ;;icali'i;iiii\ il \ III' I lie ih ii'l liu ;i l(l-llci" ilii;' si riMiiiN ciT I lif illicli Cii'i'k ilislric'l iiN (•(iiii|>iii'i'il \\i\\\ iIkim' sil iimIimI til llii' .sdiil li (iT ihc iiiaiii ili\ iilc, lllc Ulisyiiiiiirll'i<-al Niillcvs ill llic lii(illlli> nf riin-M|iiiii', Millci'. iiiiil MaNliiiliui ciTcks. MS also llic rcclaiiLiiilar arraiiiiciiiiMii dI' t lie ili'aiiiaL;c ill \\[r I'lii'cli ( ri'i l< Hals, iiiilicali' a I ill li)\vai'(l I he ikhi li ill llii-» |iarl iciilai' ari'a. 'I'lii' i > ai-raiii^ciiiciil of llic ilrailiau'i' in a lilted ilislrici is, ill a way. an imlcx nf tin' ilirci'l Ion and axis ul' lili. Fnr cxamiilf. in the cases just cited I lie t inn k st reams are si laiulileii- inj;tlieir eniiises ill a general east-west direeiion. slidwiny thai llie axis (if I he lilt is also I'asi and "est, while I he aecclerat ion ol si n^aius shows the slo|>e of the tilled siii'laee to be toward till' nor.i alioM' Ihe luoiith of the latter. 'I'hesi' two creeks, allhoii^h near tou-eiliiM-. yd iniurale in op|iosite directions, foUowiiiu' in this ehaiiLie a local \arialioii in I he alt il inle of Ihe roeks. Here. then, there' can lie no till toward the mirth: further, I here can lie iioiie to I he soiii h. else Kairle Creek would lia\e been crowded to the soiilh side of its valley. Harrison and Kaiile creeks are therefore located in a region of no I ill . proliably aloiiLt an axis away from whicli I he surface ha^ noi only been tilled towitrd the north but also toward the south, in the direci ion of 1 he 'ranaiia. forniint; a broad aiii leiiiie. ( )n I he l'"oriyiiiile Creek di'aiiia,i;e. l-'rankliii (Juleli and Napoh'on Creek liavi' unsymmel- rical salli'ys in which in each ease thi' stream has iiiiuraled lo the south side. 'I'liese lia\e also been iii\ en as cxaillples of I he i;'o\ cril- iiijr inllucnce of struct lire. Il is probable I hat no tilt hasoeeiirred in opposi.ioii to till' siruclure. and there arc reasons to b('lie\ e that the |)ceuliar oiic-siclecl \alleys are produced by the two causes aclini: Jointly ill the same direeiion. .lust aboM' l-'raiikliii (iiilcli. on the main creek, the canyon walls fall ba(d< and tic \ alley spreads out into a Hood plain a mile and a half wide and extcndiiiu' some t wn or three miles u]) the creek. .Miove this Ihe canyon isaj;ain rcsiimecl. The cause of the bottom land at this point is evidently a poiidin:;' of the water by a dam; but no local dain is now to lie seen. This is the result we should have in the evi'iit of a tilt of the surface toward llie south, Ihe tiltini:' opjiosed to the iri'adient of tin- stream not beiiifj oc.oi.iMcii.] RK( ENI' WARI'IN'fiS AS SHOWN 1;Y IH.'AIN \(ii:. 'J8i) groat ('ii(>iifj;li to rcxcrsc llic ili'iiinnL'i'. luK snilii'ifiii in i-aiiM- a ixnul- ing lit' tlic watff alioNctlu' iMiint wlicic tlic axis itusms il rci'k. Uiisyniiiiclrical xallcys «itli llii' sIccih'I' si(l(> at tlii' soiiili wcw also olisorviMl iipoii (Jlacicr and .AJilliT creeks, w lien- ;liey are iiiclnjieiiileiit, of tlie jre(ilo;,'ieal sUiicliire am! were jirolialily prcMlueid liy iiiiec|iial uplift. SIM.MAUV. I!y ail exaiiiiiiatiou of tlie Yukoii I{i\er ami Inriyiaile, .Missinn, Uiicli, and ^Myiuiok creeks it appears llial diiriiii; liie elcvalicm <<( tlio present unc()iiii)lete iiortli, hut at cerlaiii oilier poinis, as upon tile South l''oik of {•'orlyiiiile, the till appears to he loward llie soiltli. the strilcluii' hein^f jinticliiial and, according tc llie ariaii;:e- nu'iit of tlie drain ;,'<■, alon;;- northeaslerly axes. While ilie location of the axes can not ho aci'iirately di^teriiiincd. one of these jtrohahly very nearly coincides with tlio crest of the ( rookicl ( reek-riirdi ( 'reek divldo and has a direction \. 7iP M., the headwaleis of liiich (reek proiier heiii in >t»i,ii> imm ks. 'riiniunli'iiil llii- disliict wliicli li.i> I PI '('11 (li'scrilicil niiil iiiii|)|ici| ilicro iiff in nmiii'iDiiN pl.iccs \ alii.ilili' iiirlals, i ■.•<[)( ''iallyi,^!)!! I. Willi ics|iccl |i> 1 liiMi'dccMrrciicr llicsc iiM-liils iiiiiN' Ipc ili\ iilcd in Id I wocliicf ciasscs- - lii>t, IIkim' uliicli all' fiiuiMl ill llic solid ruck, lia\ iiiy I licrc hcci ii- LMMil lad'd liy (•licinical auoiicics, and, sccuiid, Ihosc which iir in rucks made lip of dclriliis dcriscd IVdiii llic uhh'r solid rucks, I'runi which dclriius llic licaxy iiidals. such as i;ul.ils, and lliesec- uQtl, jilaccr ilepusiis. riacer dcpusits arc nsnally i'uiiiid in luusely cunsulidaled river ;fia\els. In Alaska Ihc irravcls liil hcrlo wurked have been fui'iiicd in cumparalively receni limes, lint in ulher rc;;iuiis. such as I'liitish ( ulnndiia, (alironiia, and Aiislialia. I hey are ul'ieii n{ 'I'crliary a,i,'e and sliiiiitly cunsulidaled; and in sunic places il may happen that slill mure ancicnl uravels, w lielhcr funned in riVers ur nil he.iches, lia\e liceii eiiliiely cunsulidaled su as lu runii a liar(l con- jilumci'ale, while Ihey slill cunlain Ihc iruld uriirinally (ihlainc(| liy mechanical I'unci'iil ralimi. All lhcscuhli;r depusils, huwever. cunie under Ihc head (if placers. In Alaska llic precious mclals in Ihc uldci' sulid rocks, or Ihc licd- ruck depusils, uccur, su far as iiutc(l, in l\\(i chief ways — lirsl, in (|iiarl/. M'ins; sci'ond, in mineralized slicar zones. Tt may be iiolcd in passing liial in Alaska, ami lu a h'ss extent in oilier mining cunii- Irics, the term "(piartz miiiiii;;" is err.c<|iii'i]< (■ IJI >l line -^lirci ill ciilnlil idll^ 111' IllllTHl idh ; 1 lilt .O U ii l( spi'i'Mil Mini cliMrMi'ii'i'l^i li' |ilii'iiiitMi'iia llii'V may lir >ai. It. fismiis III liiiiiil III iii/i . Mii-i !•{' I 111' i|iiarl / \ lill- ill lllr I'lirl \ - ir.ilc and liircli Creek i ks are iiarni" ami ieiii|H'i-.i-iiiii \\,,-.\ uf tliem are parallel uiili ihe •.i'liisiii>ii \ . Inn xmic cin aem^v n. ,iiii| lliese usually slmu llial llnv lia\e lakeii pari in llie iiiii\ I'lnciiis of llie iiieliisini;' nieks. 'rim-e uliieli are parallel uilii lie- ■.■•lii^ln^iiy are iil'len slireil apart liy iiiiilinii aloiii;- llie .slu-arilii;' planer, nr lia\e been I'oldeil ami eiiiiliii'led (see I in'. --(; olliers elll aei'iis llie -I'll tiisily I'm- a lil I le ili--laiiee ami I lien lei iiiinaie alniipl l,\ . a> if I'anlied liy imiM'iiienl almii;' llie M'liisiii-.ii \ planes, |i is e\ ideiil lliii ilie 1 ks Were iii'iii-inally iiilerseeied liy many \ eins. sniiie nf \'liieli ran ]iarallel in I lie si ralilieai imi and uilieis across ii. 'I' lese 'ins were pidlialily iiiice imire emil iiimnis iliaii imu. Iml lliey liaM' lieeii sn lii'dken. ranlled. slieared. and separaled lliai llii'\ are imw iisiially ski't.li .il' c.piitoi't.'.l iin.l ■,lii',.il.l,.,l iiMii ■t/ v.'iit-i ill l"'>l'l\lnil.' --illNr. ini iipersisleiil . N'eiiis nf I liis class a re luiiml sparini;l.\ in lln- iimler- lyiiii; .H'ranile ami mil al all in tlie iiverl\ iny- Itamparl series. i; ■sides Ihei sheared \('ins are orieii nlliers uliicll elll acriiss III .seliistosity, Jninliiii;-. and ul her st rnci iires resiill inn- lliniimli disiiirli- aiiee witlioiil any break, sliuwiiiii' llial llie\ are laler t liaii all imi\e- inciils ill Ilie i'(«d<, and tiieret'di-e disliiiclly yuiiiiuer than llie veins just dcscril led. On l'"()rtyinile (reek I liese \ eiiis cut aemss i lie ele.-n - ajfo and llie older qiiarlz \-eins and liraneli so i lial I'l-oni a lifi le dis- lance tliey lia\e llie appearance of dikes. (See Hi;-, l'.!. ji. -y.'-J. I 'I'liey oi'leiieonlain a little I'eldspar. and sonielimes. hy increase in aimninl of this mineral, iiass into a \ariety of line pei;inal iie: this in turn seems lo lie I ransit ionai into a coarse aplii pllte. ulllcll is \ er\ aliiindaiil . In the Uii'cli Creek district, also, persistent, wide i|iiart;' veins an- found, alt lioii.ii'ti in sinaller niinilier lliaii I lie schistose veins, aiitl in tills di.sl rid also they often coniaiii feldspar, and are associaleil "iih ai)li1(\ In the rocks of the liampart series lliere are fi'cipieiil ly ipiartz veins formed aloiiii' shear /.ones. These i ks were formed practicallv siili- seiiueiit to all re,iiional seliistosily, but llii'y have been .jointed t hroiinh- f 2:'2 (iKOI.oOY (>!■' TIIK YLKOX (iOl.D DISTKICT, ALASKA. (Mil, iiml till' IimmI iiilcnsilN' III' joiiil iiii,' Ii;i -i I'l-tMiiiciil ly IhimIii 1 /.(iiii>s of sliitlil iniivcmi'iit ni' shc-iiiiiij;, aii iievei' ,slieare(l, ami are lliei'el'(ir(^ Mihseijiieiil Id all iiiiporlant iiKiveiiieiil in tlie rocks. Ml hill it CI III li' Ills iif iilili r riiiis. — III llie ohler sc-liisliis(> veins pyi'ile is \ cry ciiiimioii; $;alenii is ri'e(|iieiil, and ijold ol'l en occurs. Tn tlie l'"(irlyniile (lisl I'ie!, L mile alioNe llio nitiiitli iif |)a\ is ( 'i-eek, is a vein called l.iiwry's ledu'e, wliicli is liMo 1:.' inches thick, and lies aliim^l liori/.ciMlal ill the lied cif tlie ciecdi. This vein coiitaiiis free j;i)ld. In a iii\ ilie or |)il|i of .Miller (reek, in the same district, a (|iiait;'. ledi^e has iieeii t'omid which shows free fiold; and on the same creek is a wiui\i'\ pailx only 11 trace of t-tild. 'I'liis. however, u,i> liy nn iiiciii^ m lair saiu|ile. On tlie 1 lead waters of I he Hess Ki\ er a w c'll-Uimu n pi ■ is peel m-, ( )|i\ er ('. MiUei', has driven a luniiel J.'i I'eel iiiio a (piarl/, \ri\ixr \vliich is said to lie aiirireroiis. On 1 he riyiil -ha lid side of I he \' iiUoii, :;."i miles lieiow Taiiaiia posi, a I iimiel has been driven I |o feci on a (piarl/ \ ein in 1 he I'dreh Creek sehlsls. 'I'iie \ ciii, like so nian\ oi liers, lias liecn --o piiielieil and faillled l>y niov eiiieiils in llie rocks Ihal il c'aii liardly he followed any j;i'eal dislaiiee, and Ilwrefore iis iiiiiiiiit;- will always he\ery niieertain. A laiidoiii sample of ihisxcin nhlaiiied hy llie Survey parly. uaxc on assav o.ii.'i onnee i^old and o.:; (Hiimi' ^il\ cr In the Ion.' Ml tiillir riiiili Ills Iff iiiiiiiK/i r ri iii>:. The \ oiiiiiier I pia I'l z \ c'i IIS, w II ii'li lia\e heeii iinail'eel("d hy iiioxemeiils in llie rock, also eonlaiii nielals. [•'il'leeii miles soul liwesi of ( irele ( il \ , ( m ihelrail which passim I he Kiuiil mile . aehi', lliere is a ipiarl/. \ein carrying iiindi free i;(ild. A spec! lev ii ill 10 r poscssion from this \ ein is of 1 he lianl. w hile i|iiarl/. whieli is mil ^-eiieral'y supposed loeoiil.jn iiold. Iiiil t his speeiineii is in pJMi'es \ ei\ full of lill le I hreails and si ringers i if I lie precious iiielal; il also ciiiilains a lil lie py rile and hemalile. 'I'lii- \ ein is said In he III feel ide, and has heeii slaked hy a miner named Mel. I. ( >ii llou'ein ny I )eadwiiod ( reidi ill I he same disi riel I here w as found under I he !,;ra\ el> on Isaloirs elaiiii a wide \ein \i'i\\ rich in i;aleiia. .\ ran- dom . ninple of lliis ohiained li,\ lis assayed I I ounces in silver and no ^'old. On (ireeiihorn ( Jilleii a fi'a,u:meiil of cpiarl/. picked up in the jriavels was lull of cavities wiiich were appareiilly lefl hy llie di ii- posit ion id' mel a llie sulphides. 'I'liis fra^inieiil showed mi mile specks of free i;old, ami on assa,\ yielded i' 1 ounces of sih er lo I he I mi, I hiis suu'iresliiif;' llial il is a lii,i;lil,\ wealliered speeiineii of llie saiiie\ariely of ore v.liicli was found on llo^'em (reek. \\ llie lieaii i'f l'',aL;le and (iold I >ilsl i; 11 Idles persisieiil and w ide ipiarl / \ eiiis ar ■ said lo e\isl, the lineal llie head of (iold Ihisl (iiileli heiiiiiin places as much as l.'iO feel \\ide, and eonsisi '. ^Mif cavernous, riisly i|iiarl/.. The saino veins are found at llie head of Harrison (reek. On Harrison ( reek a block of oiiarl/ rieli in uold was foiiiid in llie gravels on c'aim ',>\ on Hie Norlh I'ork, ahiiiil llii (piarlers of a mile abuse ip lunclioil wilh III" Soiilh iMirk. The block buinil is ronnhly s.piar ■ willi sharp corners, and is aboul ."i inches Ion;:;. On one of lliela'.;e laces is ii I hi II coal in,!;- of cr>slalline i|iiarl/., less Ihaii a i|iiarler of an inch I hick. Iinbediled in I his ipiarl/. are ahnndanl heads nf ;;old. Hie larnesl oiie of whidi measured I liree-siMeenl lis i f an inch in diaiiielcr; from which si/.e llie fraf;meiils become smaller uiilil linally I hey are iiivisi- hle 111 Hie naked eye, ,ilHioui;li a iiiai;nif> inu' uiass shows llieiii lo bo ])resenl ill considerable ipi.inl il ies. dissemiiialed lliriiiiL;h llie ipiarl/.. 'J'he Ipiarl/ \ ein which carries Iliis -old peiielrales llic sdiisis nearly I AH us-^ny- In Oi.' Siirv.v w. IT inii.l'' !■> I'i'.M i i;. Mum . f I ' ! 2111 (ii:()l.n(;Y or Till', YUKON (iol.I) DISTU'ICT. AI.ASKA. at I'i^'lil Jiii.ulcs. til us slidwiiiu- 1 1 lilt it is ilistiiic!l\ younger in iiuc tli:iii tlic lillliiiM'ous ii(iii|M'isisli'lil \cilis w liirii ;in' (lidci- tiiaii I lie il<'vlci|)- niciit (if the cliicl' scliisidsity. ( )n ATiicricMii ('r('cl<. near tlic licad. UDJd-liciii-iiiL;- (|iiai-l/ xcins lia\ c bci'ii icmid. On i.iltic MyiKink (reck llic iiioviMnclil alony liic siicai- zoni's lias asiiinaliy resulted in u|ieii lissiires wliieli liaxe Imciiiiic filled Willi white, eiystalliiK' y a iiiiuer iiaiii('<| Sinclair, and samples of it yiidd on pauniui;- a small c|nanl ity of liiu' golil. Similar \eins occur on ilunler ('rcid<, bill are not known to bi' aurib'idus. Mii-riisriijiii' (irciirr( iirf (}f ijiild. ~\\\ only ' cemented aiiain by a (|uarl/. which colli a ins few inclusions, and so appcsirs clean. Thrini^ih both \ arieiics ofipiait/. run crai'ks. and at the intf r.section of two of these is an irrejiular bunch of y<>llow trold, associateii witii aiiolher oi)a<|ue min- eral, which iiia\' lie liciiiatile. The sliuhl (don;;:it ion of tlie,ydld aloiiij the crai'ks in two directions siinjicsls thai these lia\i' induced iis deposition and thai of the associaled iron mineral. The cracks are stained by limouile. showiiii;' tliil t hey are si ill callable of act inii' as channels for soliil ions. nl mm I! !i MINERALIZED SHEAR ZONKS. The Veins of pure white crystalline i|uart/. which have lieeii described ofien shou by I heir co!'ib si riicl tire, or even by I he lea\ ins; of residual cavities, t lial they are hlliuns of preexisi iiiy- open li satires, nnil it is iirobable t hat this is usually the cise. In ot her iiist.iiiccs, ]lowe\er. silica and melallic sulphides lia\e been i.itroduced into the 1 k ilia i|uile ilill'erent way. Where rocks liase been profoundly sheaied. so that wliilc no open lissiire is presented the whole crushed I'lick oll'er-. a ready (•h.iiiiiel for percolat iiiy waters, both the she.-ired rock and t!ie more massive portion iniiiiediau ly adjoinin;;' are usually fonnd fnrllier altered by chemical means. This is especially 1 he case wln'fe the I'ocks ale on the whole massive and are milv locjilly sheaied, so thai there arise delinite shear /ones, almi^' which llie Water circnl;it ion is ii ssarii.v concentrated. l'"or this reason the slicar /.ones are most conspicuously altered in the {{.imparl series rocks, since in the older lormalioiis the shearini;' is more general, and in the yoitimer ones il has not been nearly so yfeal. The chemie.il ClTccIs alolii;- these shear /ones are liol ice;|lile in llle tield ehiellv bv SI'IMllv.) MIXER ALIZIMi SlIKAK /.(iNKS. 295 ill) iiiiliiral iiiii wliicli iiriscs rnim ilic ilc'iinsii inn ni' -^iliiM. iiinl liy ;i staiiiinu' i-i'sulliiii;' I'l'inii tln' loMaiimi >licai' /(iiics while i|iiarl/. mmiis rm-iii. cvidiiilly uli'-ic aciuai li->in'c> lia\ c oxislcil, Inr Ilii'v alv.axs cdiitrasl >Ir(iiii:ly willi the Maik, iiii|inri' JasiHTnid (ir I'hi'i-I wliii'li iiri--c'-- rinm ilic >ilicilical inn nf the (■(niiiliy I'ook. nccri.'KKNcKs. Aliovc I''i)flyinllc Cri'i'U. in t In' >riiist^l^in sil\i'rainl s;;!', in LTnid. Mr. McCoiinell' miles laal lieluceii l-'di-lyinile (reek and l'''i't. K(>liaiiee eoppei' pyriles ill small iiiiaiil il ies 'iirs al sexcral peiiiis, nol- ill llie xeiiis bill as Miipri'irnaliiiMs of Ihe sehist ilsell'. ( )n l''(irlyinile (recdc. J nr '■'> miles almxe I he nmiil h, are shales, sand stones, and liineslones wliieli liave lieen liieallv sheared and inipreL:'- lialed wilh slll|)hides. alllioliuh on Ihe nnli-mps nmsl nf lln' sulphidi'S haM' lieen leaehed out, making; the rocks rnsly and erumhly. On ('(ine Hill, direel ly opposile Ihe monlh of Clin Ion ( i k. Ihe i k is a limestone, soinewhal altered, 'rhmniili this .'lilered mek run- .1 /one Ji«i oi' :!i"i feel wide. \vhi<'h is eonspiennus al a "lislanee on ai-iiiniil nf a dark-red slain. 'I'ln' rock is found mi fresh break- im be >laiiU'd screen, and tn be made up lari;cl\- (if line eryslalli '■■. with considerable (piart/,. 'rnis /nne enl- serlieally 1 . . il.e less altered rock in a mul Invest -snnl heasi di reel inn., and appeal's to he eontiiimnis and nnfaiilted. bill'iwini;' a -el nf vei-ii.'al jo'nt-. I mhi- thi' miernseiipe the allel'ed rnek i- seen In be still essentiallx a lill"- jfri'.ined. erystalline dolmnile. sniiiel iines eonlainiiii:' eh lienmlile; then' is alsn a litlh' cinarl/ in very line iiariieles. as if sei-mnlary and in process of i'epla<'iirr H arbonale. Small mas-e-Mif a dark-bi-own nietallie miiiei'al, snrrnnnde.l by a sli-hl slain > a silicate ni- ,|nail/. and Ihe slain is some compoun;! of chromium, nndonbledly dei'i\ eil frnm Ihe oxidation of chromiti', whii'h is the iiieiallic mineral aci-ompanyiiie- the u'rccii slain. Asampleef thi-altci'cd rock was assa\ed bylheSurve> and slinwed jn> ji''il'' "I' silver. It is r'laimi'd, Imuevcr. that ntlicr -am|ilcs ha\e shown Ihe lire tn be a Inw uraile 1:1 hi ore, capable of beiny: worked under favorabi idiiioiis. .\cconlini;' lo .Mr. Oijilvie,' of Ihe Cana- I .\r,ii. li.'i.l (l.'"l. Niii Mi'^i, Sui'vi'v 1 iiim.lu. V'.l. IV, IwM-sii, p. :ii)t). ■•^ii t 2116 Gr.oi,o(iv or the yuko.v gold district, Alaska. :t i.' Ui .'.(, C tlie ( aiiadian Survey, yielded o\ci'.'!S ounces of siivei' to the ton. Ti'aees of li'old and siU'er were found in a s|)eeiiMen of alleien .\merlean (reek were oliservcd nunieious shear zones, aloni^ Avhieli I he roek was sillcilied and eonlalned, besides ealeite t'opperand iron ])yi'ito. In the jrravels in the bottom of the creek is found mag- iielitein good-sized, walerworn pebbles or in small, pei'fect ei'ystals, aTid also much barlte. I'"rom the association with fragm(-nls from the ad.iacent rocks It is probable that these nnniMals are likewise derived from shear-zone deiiosits; and it Is <|ulte likely that the gold itself, which occurs 111 coarse fra.u'mctils in the .u:ra\els. ma.\' ha\<' the same origin; therefore, bed-rock di'])osits of considerable richness maybe found on American (reidi and \icinily. All through the Lower Ramparts of the Viikon the rocks of (he l{am- jiart series are much .jointed and are locally sheared. These shear zones are sometimes imprei;iialed with Milphides, and often narrow (piaitz veins liasc ''lU'iiieil conformable wlili the shearing. The \('iiis are sometimes slightly cavernous and ri ; ■,., showing the decomposi- 1 1on of l)ree.\ist Ing su.'jhides. .Mioiit l'.T ii:i|es below I''ort Ilaiiiliii a sample was taken from a sheared zone in a dark aplianitic rock. Along this zone the I'oek was decomposed and yellow, 'j'his saniiile, assayed by .Mr. U. H. Ollieer, of Salt Lake City, gave (l.ns ounce gold iind a trace of silver. I'nder the microscope the rock is seen to be a InlV, consisting of a line-grained groundmass in which are .s<'attei'ed rounded in'oduetion of kaolin, chlorite, epldotc, and carbonates disseminated throughout. The elTeci -- of pressiirearo shown by a strong set- of ii'regular but generally jiaiallel fractures. Along those are occasional veiiilets of cry|)tocrystalliiie silica, dark- brown oeherous linionite or blood-red translucent hematite, a milky- white, seinioi)a"|U(> mineral which is ])robably siderite, and a \-ellow- greiMi mineral of eousiderable single refraction which was not deler-, mined. Ill the l{am|)art rocks on ^f.vnook Creek tlie same |ilieiiomena were noted. The alteration of the r()(dl»per })yrite. The inti'fsl ices between the (plariz iriaitis appear originally to liave been lille. ('. .Miller. .*v sample a.ssayeil for theSiirvi'y by I'rof. ('. I-'.. Mitnroe jiave uold ii.dn. silver ii.i"t; one assiiyed by .Mr. i{. 11. OtVicer, for ihe writer, iravt' a Itace of u'ohl, and silver o.l' ounce to the ion. It is claimed, however, that |ifevious samples liave siiown considerable (luantities of the precious metals, one iissay lieinn said to inivo shown xl".ii'i 1o the ton. .\ sample from one of tliede|iosits in .Miller (iulcli, tiicnt lotted above, showed no trace '.if jfold or silver in an assjiy by i'rofessor .Muni , while one by .Mr. Ollicer showed irold n.id ounce to Hie ton and a irai.'e of silver. On Hunter (feck ate similar ittii»rc.i;tiatiotisof sulphides, vvhieli are ehielly pyrite, ntarcasilc, chalcopyrile, JUid sottieliines iiyrrholito. Al ono i)oint ii tunnel has lieeii driven on a black, carbonaceous shah' wl.'ieh is interbedded with diabasic lull'. This shale is in portions silicilied and contains much pyrite. I'mlerthe microscope it isfotind to be orii;iiially calcareous, but Ihe imIcIIc has been largely replaced bv pyrite, with some chalcedoiiic silica. Thisroidc is eliiitiied lo have shown siillicicni v;ilites on assayiti.ij; to make it ii low-5,'rade ore, but the jissav b\' iheSiirvey showeil o.lio ii'old and o.ii.'i ounce silver to the ton; however, this was, nnfoiM iinately, of a specimen and not of a Ciirefullv selected itssay samide. GENESIS OK AURIFEROUS QUARTZ VEINS. It has alretiily been noted that there ate in liie iroltl-beai in;; rocks of the Vtikon district two chief sots of ([imrtz veins, one of which wtis fornieil previous to the scliistosity and one subseoiiettl thereto. if II 298 (ii:oi.()(;v oi' tiik vikon gold nisTiiirp, af.aska. ^ u Ilc.-idcs llicsc 1\v(i cliii'l' si'is. ilici-c ;iri' riT(|nciit \ciTis si'MiitTcil lici'o iiiiil tlu'i'c tlii-iiiiL:li till" yiiiiiiucr idi'ks. Tliis is wliat slmnlcl lio f'xpcclcil, since silica is cvci\ where heintr taken inlo soliilioii liyurdi- nary alkaline walcFS anil |)i'('ci|)ilateil I'nmi llieni, so llial ticw (ie])()sit.s ar(> roiidiiually rorinecl in favorable ]ilac(>s. liiil lliese yoiinuest veins ai'c scatlereil and belontr In no delinilc syst<'ni ; and. so tar as knou ii, llieyare of no econonne iMi|iorlance. The veinsol' I lie I wocliicl'sels in (lie schist use I'oidvs, liowexer. are c\1 1'ciiiely nu Microns and i iiiporlanl , and both sets appear, as deserilicd, to he aiiril'crons. The older set; has been so sheared t hat its relat ions are ureally oliseui'cil : (herel'oi'o llie yonnircr set, which has been left nudist urbcil. olVeis the best facilities lui'slndy as to nalnre and origin. 'riicse yonni,'ei' \-eins lia\c a close and evident connection with acis of (he foi'iiiation ol' the-:' la\ as is qiiile open to obsei'V al ion. < 'u i he other hand, the deposit ion of \einsaml \ein material from clrcnlalini; waters is a jiroccss which nuiy be everywhere oliscived. both at the surface and, to belter adxantaLT' 'c, in unileiuround e\ca\atious. \\'ith (his preconceived idea of the utter dilVereuce in manner of deposition of the two classes of ilejiosits, it has hapiiened naturally (ii'.xr.sis OF Aiiarr.iKus (,m mm/ \i.i\s. ■_'lil» flint nicks ])M'sciitiiii:- ;i |icclVct I i-Miisit idii Ipciuccn ilir iu(,li;i\i' loiii; been ;i SiHII'<-c of i'(ili>iil.>i;ihlr |M'l'|ilcxily Mini (•(iiilclilinii. Tllc-c transit idii nicks jii'c cliidly kiiciwii as iicirnial ilcs, and have liccii rol'crrcil by suiiic to ihc dixisinii n\' diko and Ky soinc In Ih.il <>( veins, since some nliscrv cis pcrcciv i^l dcar'ly cliaraclcri-.t ics |i(iiiiiin.i; tn an igneous ni'lyin and sliuwini;' rckilion In uranilcs and iillicr crvslaliinc nHdlallinc aizLii'i'^ales ni' (|ii;irl/,, fohlspar, ami other nuiieials, knnwn chiclly as |pe^maiile. have been formecl under enndilinns inlcl'mediale belween llin>c j:n\ei'llini;' I lie foi'malinnnl' acid iyneoiis rn(d line of demaii'ati(Hi between dikes and veins has been 'Ori(tiii"t pi'l-'iii'itiii', liy W. ( i rr,.sl.y ,iii.l M t. t'lilln-: .Viii. (i,'..lMi.-ist, Vnl. .\M.\, N..,:i, |.. I ir, 'Hif Miiu'ralipii ili-r S.vi-iiit|ii-u'iiuitii:.-iliiac- ■|i-r si'iilii[.i'wi'«i>.lii'ii ,\ui:ii- \iiiil Xi|ili>'liii-.viiijii', l.y W. C. Hi'mu'lT'T: X.'il^.lir. liir Kl-y-l, Vi.j. XVI. |M«i, iMi :.'t.-i-:il.V aiirigin "f M:iryliiMil |..'i,'iimtiii's, liy (), U. Williiini-: l'"!!!!'!'!!!!! Ann, Kept V. S, cir.il. Surv.-y, 1.-V1-), p, ilT.-i. <0)i, I'll,, iiji. I.v;, lT:i. •Dp. i-it.. p ii;!i •Sixteenth All" H.pi, r. S. (l...! Survey ravi I. Imm; p. li-ss ^ -*' 5 4^ ■I .•{()() (il'.Ol.OdV OK Till'. YCKOX (i01,l> DISTKICT, ALASKA. ..il li '•!! ]Miiiili(| ciii'i liy Criisliy,' while \'iiii llisc- lias rciiiai'kcci iipdii Ilio improliahility iif any ilt'liiiitr (li\isii)ii hciwccii (lie a(|iic'oiis aixl iiriicDiis |)niccsst's at iiindt'ialcly rciiinti' dcpllis, wlicrt' the iiicfcasc of pressure ami leinpei'al lire must j^hc siic-li irreal alisni-lteiil power to li(|ni(ls: aii considers iijncous, liow- e\-er, Williams's \iews are, in the main, in a( rd with the other opinions already tciven and with those held by the jiresent writei-. In rejraril to the relations between pejj;matites and icraliites. the.so views are .so clearly and forcibly slated that the\' may be (pioled. ■' The writer's coiu'eiptidii ef tln' relatiim iK'tween tlicKo iiitnisivc |H',:;iniititi's iiml the ;roducts of the residual, and tlierel'ore most aciil. ixn'tioii of a granite magma liigldy charged with water and other miiu'ralizing agents. .Such a sili- ceous material, in a state intermediate between fusion and solution, has lieen iniected into fissures and there crystallized into very coarse-grained aggregates, not necessarily througli any great slowness of this jirocess, but rather in virtue of the aid to crystallization alforded liy the al)undanee of mineralizers present. THE <)|{I(il.\ ol' DIKKICKKXCKS I.N lO.NKOl'S HOCKS. The transition in the I''orlymile ami llircli t'reek districts of ai)lites thr()ii;j;li inlcniicdiato [)Ofj;niatilic rocks to (luartz veins is a case strictly analof^ous to tho casus which have hoeii cited and which have given ri.so to tlie views inferred to, althou}j;h in tiiis cas(> the pejj;matitie rocks are line j^rained and relatively rare. On Fortyinile (.'reek, how- ever, tJjo Iran.sition from (|tiartz veins to a])lite is not more eoiniilelo or remarkable than the transition from aplile to acid .ufranite, from ncid Ki'ii'iilc lo basic granite and diorite, and from these to succes- sively moni basic i-ixdcs, until tinally rocks consist ing essentially of the ferroniagnesian and the metallic minerals result. All the ditl'orent • Oil. lit., i>. im »Oii. i-it., p. list. ' Op. elt., p. flW. "^ Sl'IKII.I liKNESis OK Ariiii r.Kiiis (.;rAi;iz \kins. 301 Viiriclics oi'cui' ill llic same iiri'ii us dikrs wl.icli li,i\c Imch ini iikIciI sucrcssivi'ly iiii'l wliicli cut (nic aiinilicr. In view of this rciiiiifkjilili) ti'aiisitidii and ol' the I'luisaiiiriiiiiity hftwccn tlic ilill'ffciit \ ai-iii jcs, wliicli lias Ihm'Ii pointed oiil more fully in tlie detailed eoiisideral ioii of tlu'se dikes, the liypot liesis siif,'t;ests itself iiniiiediately tliat all tlie rocks liave in some way a eoininoii ori.Lrin. and thai I he cliiVei-eiit pliases liave sepjiratcMJ out under jfradually clianiiin;; eondiiioiis. Ill liic lifjlit of tlie most modem peti'oi;ra|)liy it lias eome to lie rtH'ojjjiiizeil thai there are no sliar|) lines of division hetwei'ii thedilTer- oiit ii^neoiis rocks, for one variety passes into another so ;:radiially that the limits niiist lie drawn arbitrarily, and in some cases the best classification whicdi can be made seems artilicial aiii iiici Mini |ii'r- I'ci'l iTysliil> ;i pi I'ss which rciiiiii'c^ m ri)ii--iilriul)ii' iii(i\ cniciii of thi' niiih'CMJi's; miiiI the crysliils l 111' I'liriiirii ill iliis \\;iy. In llif iMlinraliiTy the prniTss of srirri'L;.-!! ion rrri|ii('iil ly jh'Is so llml Ihc in.-ili'iiiiis .-irc scpiiriili'il not (inh mil) siiiixli' crNslnls, hiil into lni Mi'lii's iii.'iiic III) of iiiiinv liki' I' Ifils; ami the iiiii>--i's of the ililViTiMit miin'i-als arc more or less per- fect ly scparatcil. in ilic sMiiie way it occurs in ininoral \ciiis that cerlaiii minerals .-ire sei;ic^atcil in iariie liuiiclics in parts of I he \eins, while other minerals are colleelcil into other parts. In iiincinis rocks lliere are ollcn small patches where certain const iliicnts an nceii- Iralcil ill such a way as Id place it hcyoml iloiilit that they lia\ e sc^re- jralcil ill the s.imc iii.-iiincr as a siliL;'le crystal sc|ia rales out from solu- tion: .■iml from these small patches there is a urailat ion to lari;'cr I'oisk masses, which have markeil ililVcreiices in si riict lire ami eompusition froiii the rest i.f the iiriieiiiis holly of which they, Hex eri heless, I'lirin an essciit ial porlion. It is thus louml that in a laritc igneous mass ililfereiit port ions have slight ly ililVei'ciit characters, ami theiiica nal- iirally follows t hat t licsc lariic ililfcrciices ai'e iliic to t he same i;encral causes w hich has c pioiliii'cd the scL;rc,uat ions of minerals on a small scale; or, on a still smaller scale, the scerc,'.;;it ion of imlixiiliial cr\s- lals. !• ollowiiiii' this lint )f thoiiirhl still further, it is pen •ei\eil that ililfercnti iii'iicoiis rocks in a ;;i\en district, while showini;' throiiulioul certain constant |ieculiaril ics, all ,u;railuall\' jiass into one aunt her; and the expla iiat ion iiat 11 rally siiu'i^ests itself that t hesc dilferiiii;- rocks havi oriuinatcil hy t he same process of sejiiciiat ion t'rom some iiioi'c uniforiii iiiauiiia. I''inally, modern iielro.nraphic research and comparison have shown that, altlioiii,di the classes of rocks are essciit iall\ t he same in all |)aits()f the world, all tlie rocks of a jiiveii district, taken collcct- ixcly, often present cerlain constant dilferences from those of iieii;li- boriiii,^ districts; and hence t he t lieory of se.urei;al ion or dilfereiiliat ion of the oriuinal coiniiion niaunias of these dLstricts from an ori!j;iiial universal mai^ma has been coiicci\eil.' Till: rlii;.MIr Al. VAtMAIIitNS I H' lirKKS. Ill seek ili,ii proofs for these liy[)i)t lieses, we should iirocccd from the W(dl-estal)lished pheiioiiiena of sejiicnat ion on a very small scale to eases iii\ olviiiii; siiccessi\'ely lar,L:;er and larirer masses, 'riierefore the eliaractcrist ics of dikes and other masses of intriisivo orii;in whose boundaries can be traced oll'cr a very att fact i\e field for study. In these rocks it is often found that there is a marked dilferciice, both cliemi<-al and structural, in ililfereiit portions of the same boily. 'i'he slrncliiral dilferences are shown chiclly by dilfei'ciif dciirees of crys- lalli/.alioii; and usually these ditl'ereiices e\i(b'iitly depend directly upon the rclati\e proximity of the wall i k, those |)ortioiis which are .1, 1'. llUiillK'^, Tllf i.l-inill ol ii;ri,'.JU,, l-,»k^: iillll. i-ili..!^. S,.,', W'il.-llillKtoll, Vol. Xll, p, 1S.V V (ii;NK«-is or .\it;iii;i;()rs <,.ia1!I/. vkins. 3i i;? iicMi-"'-.! 111.' Willis liiiMiii;- ill ^'rii.Tal ;i liiirr I. •Mini. ,-iii,| iii,,v,. more ll'lllulr llcillL; iM.IIMT. Il is I'll-iir llllll lllcs.. i|i|V,.|,.||i-r^ mT ^IiiicMlllc. \vliiclicli.|MMii| MPiJiicTi'v II I Mill till' iinsltiiin .if I lie \\;ill r.i.k, .iiiiiiiMl.-.l sllliM'i|l|.Mll t.i 111., illlrllsiiili 1.1' till' .like. ( 1.11. ■.•111111- 111.. .■Ii.iiii.'.il .li^V^l•ll<•.•^^ ill .liKr>ill|i| ..lliiTilili||>i\(. im;i-.-.'s. il 111,1 \ liki'W i>.- l... •..liil llial. if ill iiiiv iliki' ..r .iilicr ini riisi\ .. mass ..I' ii;iii..ius in.'k .■liciiii.-al \ aiialiiiiis sliiiw (liii.ci and (•.iii^lanl i.'lalioli l.i |ir.i\iiiiil y t.i llii> si.j.'s or ct'iiliT. il is sliiiii;; cviilfiiiT. aiii.iiiiil iiiy- aliimsl (.. |iiniir. ijial tliis clii'iiiical vai'lalliiii caiiicalMiiil siili>.'.|iiciii i.. ih.. im iiisi.in mi' i li.. r, ..^k ; riirlliiTiii.ir.', |)r.>\ idcil it .•an li.' |ir..\..i| thai lli.'>.' \ aiial i..ii- an^ in.l.-- p.'ii.l.'iil ..r 111.' .'Ii.'iiii.'al variali.iiis in lli.' wall in.'k--. ii is \.'i\ slr.ni^' <'\ ill. 'life thai tlii'V lia\.' aris.'ii by a iinicfss .iC s.^u'i.'iral imi. tin the (illi.'r lian.l. la.'k .if siidi rciatinn is im |ir.nit' airainsi I lie iiii>siliiliiy .if si'U'r.^ual i.in. l)r. (I. II. Williams' lias .Icsci'ilicd llir ciiiilai'l |ili.'ii.iiii.'iia ..I' .lik.s llitriisiv.' iiil.i iiiii'M s.diisls anil liiiii'sluni's in Ni'U \nyk. in mhh.' nf llu! narr.iwi'si dik.'s I ln' iial in.' ..f I lie ('iii|il i\ .• r.i.'k (.li.irii.^) i-. .•.in- .sidt'ralily all.'M'. I ii.'ar I lie .'.in lad. < >ii.' .if I li.'sc .lik.'s was .mly .iii.-- fljjlilli .if an ini'li w i.lc, s.i ilial I li.' fill ir.' w i.li li was .•niiiain.'.l w iiliin llu'lliiii si'cliiin sludic.l. 'I'lic iiil iiisivi' inat.'iial cunsisli'd ..f Innii- lilcnd.', lli. Mil.', apalili-, an. I |ii'.ilialil\ s.'aji.ilil.'. ami tlic liiiriilil.'ii.|«> was .•nil. •.•Ill I a I. 'I I a 1.1 111;' III.' .'dii.'s iil' I lie dik.', .il'l.'ii slamliiii; |M'r|p.'ii- .liciilar I.I ils walls. In lliis cast' llic w..ll i.ick was liiiicsi.in.'. I'luf. A.V. I.awsun '•' ili'si'iilics ciTtain dikes in tlic ISainy Lake it'^ri.'ii wlii.-li sliiiw in a iiiai'kc.l dcuri'i' variali.nis nut only stnii'tiiral lint also iiiiii- cralii.^i.'al ami .•licinical. ami llicsc \arial inns a|i|i.'ar \ cry .•.nisianl ly in dilTcr.^nl dikes In lia\ .• I li.' saim' I'.'lali.ui l.i lli.'wall r.i.'ks. i''iii' examiile, in a dike I." i feet wi.le there is a ura.lal i.m in leMiire from an a phalli I ie rock ai the eon tact to a eoarse Lraliliro or diorite in ihe eeiiler. Ill 111.' same dike there is a miii.'ialoiii.'al \ariali.iii fr.nii a (|iiarl/,les> rock ai the dike wall to a iinartos.' one in the eeiiler, ami also a yra.liial change from aii^riti' to hornlilemle as the mi. Idle of the dik.' is approached, tou-cthcr with other w.'ll-niarke.l dilVcreiu'cs. ('h.'iiiical analyses show that the rock in the mi. I. II.' .if the .like e.iii- tainsalionl Inpcrceiii more silica than Ihat at I he >i.lcs, a .lill'.'ri'iico w liich is siitli.'i.'iil to SI 'pa rale the parts iiit.i I wn .list in.'l r. ick sp.'cics. I'r.if. ,1. T. I.l.liiiiis ' olis.'r\ .'.1 in a certain .like that lli.' iVrromaiiiiesiaii elenicnts had liecii part ially I'onceiii rai.'.l aloiii: I he siiles. aii.l ref.'i-s t.i I.aji'orio as having iiiaile the saiiii' oliser\ at ions. Sir .Vrchilial.l (ieikie' has lirietly descrilied certain iiitriisi\e sheets of dialiase in the liasiii of thi' Firth of I'"iirlli. Near 111.' coiita.'t with sandstones or shales Ihese diabases ha\e an abiiiidaiicc of oliviuu, 'Am. .T.nir. Sri., (i.^t., Iws, M siTi.^s. V..1, .X.X.XVl.p :;.V.i. ■Pi^tr.vmpliii-al ilill'iTi^iitiuti'iii nf .-.•i-tiiiii ilikrs ..f tli" Hniny I.:ikr n'lti.Mi: Am. (l.-.plnttist, Miirfh, IMil. V.il. VII. IP. 1.-hI. »Tl.onriirj,i,,f jir,„.,„i.,;|.,„.l(s: HuU. Pliil''.^. S.I,- . Wa~liiii>,'t..n.V,.l. XIl. j,. l.W. < •r...\tH.«ik nf (i..|iloKy. :!,l ..clitiiill. l.-'.l.l. p <>'■'■ I 1; m\ 304 (ii;(iI.u(;Y (iK Till'. VI'KON (iOI.H DISTNK'T, ALASKA. wliicli iliiiiinislics ill |)ru|Miiti<)ii as tin' ilislii riciiii llii' I'oniaci is increased, until in lliecenterdrilie slieels il clisappears. 'I'lic inlerior purls are also Con nil to lie mure aeid than the exterioi'. Sii in tliis ease the wall I'oek is ol'teii samlstolie. it lines iKil seem pfolialile that, it ean lia\e hail an.\' inlliienee in iiiai;ncsian minerals. The dill'erenee in amount of silica, liowever, is slijrht, the extremes falling i)rol)al>l\ within I jier cent of each ollici\ Kouqili'' ' has also deserilied certain dikes the wallsof which are more Soiceous than the ci'iitral part. From the fon'fjoiii}; oliservalions it apjiears that there is often a systematic \arialion in II hemical composition of dikes, which has a constant relation to the proximity to the wall rocks, and that, as a nilo, where there is such \'ariation the outside of dikes is more liasii; tlian the center, altlioujih sometimes the reverse is tlieca.se. .More- over, ill many cases this variation can not lie ascribed to assimilation of the wall i'ii(d<, and must be explained by sonic process of chemical seirrenation ; and from tlieielalion Just iiointed out it seems jirob- able that the causes of these scirreuat ions are ditl'ereiices in 1eiii|iera- tiire, since, as a rule, those jiort ions of the dike nearest the wall rocks would become cooled most i|uickly, althoujih in certain coiicei\ able cases the reverse would happen. utiiKU tn.' srcri:ssi()\ ok i.avas. Where lavas liavt> been erupted at ilitTereiit jieriods from a sin;rlo volcanic center, pet rouraphers have thoujrht to have discovered ileti- iiite laws of succession, sliowinji; thai in the reservoirs beneath the venl the molten rock was underfioiiii; a jirogressive chaiifie in chemi- cal composition, and this <*han^i;e has been asci'ibed to sef;rei;atioii or (lilTcrentiation. 'I'lie usual law of sllcccssion, as interpreted by IddiiiKs,' is that the series bcirins with a rock of avera^re composition and passes tliroiii^h less siliceous and more siliceous ones to rocks extremely liij^h in silica and others extremely low in silica; that is, ' Tlif ijranitc at MnniitK Atliun aiul Eve. Wiii-wick. Oraiij^c ('(tunty. Xf-w Yurl^. an|..u'y „{ the ICureka District, ii. :.".'.'<. ^ Sautorin ct si's (.''ru])tiuiiH. Paris. l.sTl'. \t. ;tii4, <()p. tit., p. U"). h i! (il'.NKSIS (ll- VURII'KKiilS i.HMT/. VI.INS. ;5o:i tlic scries (•oiiiiiiciici's u ii li a iiii'iiii iiinl nuls \\ il li iai rciins. I'lmn si 111 ill's ill llic ri ii|il ixi' iiirUs 1)1' Niirwiiy. l!riiLr;;i'i' aU" 1 liniijrlii ii> lia\ i' ili'li'i'iiiiiii'ii a ilcliiiili' law 111' sni'iM'ssiuii, hy \\ hirh llic iipcks |M-(iL;ri'>M'il rroiii tlic iiinsi liasii' tollir II livt ai'iil \ afii't !(•■«; ami tiriUir.' I'miii a sillily (il llii' i;riifi'iis I ks in Srollaiul ami iii'i;;lilMiiiin.' ifi,'iiiiis, lias mini' ((I I 111' saiiii' u'i'iii'ial I'lPiii'liisiuiis as In I hi' siu'ci'ssimi. Allliiiii(,'li till' iilii'iniiiiriia ili'sri'ilii'd ami llii' laws licilui'i'il h\ ijicsi' ami uIIht i)hs('r\ CIS ilillVr in ili'tail, yd lln'\ all si'i'iii In iiniiii in a ili'liiiili' nnliT III' siH'i'cssioii ill la\as piniicil (iiit al ilillVii'iiI liiiirs in llic >aiMc vnl- I'anii' ri'j;iiiii; ami il' lliis is I'slalilislu'il, it pniniN liihi'i' in I'lii'iniral si'i;ri'iral inn nr In a sysli'inalii' ni'i;:inal ililViTf'iii'f: ami nl' llii'si' Iwn alllTlial i\ I'S llli' rnl'liMT nll'iTS liv far lIlc TcWiT (lillicllll ics. ('uni'iTiiinf: llii' ilill'i'ii'iii'cs in llic natilii'iii' -.iiicosinii whii-h lia\i' lici'ii nlisi'i'Vcil al ilill'iTi'iil \nlcanii' ri'iiii'is. il may lie nniarki'il llial, cvi'ii willi a lixi'il ili'liniii' law nl' si'U'ic^ialinn. Ilii' ni'ilci' nt' iTuiilinn wniilil III' ililVi'ii'iil in liilTi'i'i'iil rasi's. hi'ini^ ilriii'iidi'iil 'i|inn a j^rral nil 111 Iiit nf ilisi iiiliiiiL;- ami alii'i'in^' iiilliii'iici's, many nf w liii'li ii'ailily sii;r;;i'sl llii'iiischi's. Imli'i'il. il wniiM lir nnnaluial if any iinil'nrni I'lui'i- sliiiiilil nlilaiii i'\ I'l'.vw lii'ir; inil liy liri nl ami rarcfill si inly llic general law slimilil lie fniiml wliieli wmilil in a laiiic iiumlier nf cases jircvail n\ cr all nlliers, ami wniilil lie |ieil'eil ly illiisl rated w Inn enin- plieal inir liilliieiiccs were ahsciil. while in nilier cases it wmild 1 me cliaii;j:cil iinlil nflcii the succcssinii i>\' lavas in a ,i;i\cn distriei wmild he iliiilc witliniit a I'ccnuiii/.alplc plan. The laws already ilcdin-ed li.\' Iddiiijis, l>ri'i>;^'er, <;eilile cmidil inns lends In sc|)ai'atc lull I a iimrc hash- and a innrc acid |ini't inn: and in view nf Ihc cniisidci'iltiolis which have liceii poiiilcd mil, this may he aceeplcd as {111 jiypiithcsis which, alllimiKli m'l yel alisnliitely prnved, isslrnimly Sll|)pnl'lcd liy facts. The aceeplaiiee ii\' this cnnilll--inn as tn the cnicacy nf se.Hrcu'.'ll inn In priiilllce dilVcrclll inek t.\pes lines lint cniii- pcl lielief that all rnck types ha\i' thus nriiiiiiated, ni- that the types which have lliiis lieeii Inn 1 ha\e sprung- finiii unifnini iiiaLrinas. s.Miin: cK riiK sKinii;i;Mio\ I'liei »>sns. ('oiieci'iiiiifr the prncesscs hy which the separatinli nr seLrrc^atinll nf the imire basic fiinii llic iiinre acid ruck eniisl iliieiits takes |ilace \ei'y little can he said, lirtiirircf, N'niit. and Iddiiius' apjical in fniin> nf innleciilar flow t he applical inn nf \\ liich is nnccrlaiii. The law rejrard- iiiU' (his is kiinwii as Snret's principle, and is llial innleciilar cniiceii- Iratioii iKiiy he caused liy dill'crenccs in teinperaliirc. limirtrer ' alsn siii;ficsls that ill the same time a partial cryslalli/.atinii iiii.i,dit set in, and ])rndiici' sofjrcKalinns i<( the ninre basic iiiiiicrals. 'IilditiKH. oji. fit.. V ViS. ^Iddinns, lip. ■■!!.. ii. 14H. 'Op. rh , p. t.V.i * Miliums, oji. I'il . ji. 1:^1. IS GEOl., VT 3 -(» 'I '^^ II ' V ,'(ll(i (iKiil.iKn iiK IIIK YIKON lliM,l) DISIIMC T, ALAMKA. Till- rlVici iicy ■it' iiiiilc'ciihir' ll l>"cii miuM'cI in llir laliurjilitiy, aiiil is a<'i'i'|)l('il a- Ih' lll(■arl^ liv wliii'li llic ;jiihm1i nf crystals takes plai-c ill siiiiil idiis ami also in rucks. Mr. (i. I". I'cckcr.' Imwcvcr, ai'^'iio that iIiIn pfii- ^s^ is sn >l(i\v iliai the scpaialiun of aii\ cuiisiil- craltlc liiiily III' ruck into iiiorc aciil ami iiiurc liasic |i and mure nr less completely, accord ill!.' to tic r !elati\ c specific ;,na\ it \ . liy sinli ciir- rciils t he liirhter parts wniilii lie carried farther than Ih- ilea-, id, and j( ciiiiceiil rat ion would lie elVecteil. depeinlenl upon the Clint jniiity of tile ciinreiits .iiid oil the perfect ion of t he t>rii;ii;,il chemical separa- lioii. 'I'lius Usually near tlie cooliii;; walls of a limlx oi iiiiieniis rock lliose |Mirtiiins which solidify lirst, that is. the more basic constltii- I'lits, will lie precipitated, and the c|iiTcnts will coniiiiiiiilly ••nvv^ a\va.\ the r'-.idiial liH:htci' materiai and mini: new supplies of Miii|i!1ei- fiitiated tliiiil. In this way the eil;>cs nf a ruck mass ■hoiild lie. as a rule, more !• .sic than the cemer, which is the cnnc'usi n at wliidi we lia\ t' art'' > cd from the lecnrd • fac's;fiveii aliove. .Mo:e \ ioh nt cur- n'li'.i, liowevcr. Would carry liolli liutilerand I avicr matcriiils aloiiu: tii^ctlii'i'. and miLTliI cause a complete minuliny. In this wa\ lluiils which hail separated inin dilVcreiit port ioiis iiii>:hi lica^iain united 'I'iie ditfereiit prnccsses irniN hi iiiparcd In tliiactiiiM of water on nick del I it lis at the surface. .\ cnmparat i\ el> uciitle stream tlowiiiL; over lii'tero;;eiieiiu^ rock fra^m ills liriiiirs alioiit t he sciiaralioii ami ' s.iihi i|iiii'h- 1.11 1." k iliili iit!ii;i .\ .\iu I"! r s.'i.. nil ■„-n. .,. v.'i 111. ivi;. |.|. ■;) in. t ) . (;p:m:si8 nr aiuifkhih s (.haimv. \kins. 3n7 assort iiH'iit (if 1 'ir tVii^iiiU'iils .-ic'CDriliiii,' III si/r ,iii'l >|ii'ril'ir Lrr;i\il\, foniiiiiir at oiu' I'lint ,i li.'d nf ciiaisi' iffavi/l. ami at aii'itln'f a layci' (if tine sand, and also In lii,u:iii,i;' alimit I'liiicciilraliniis ul' tlii' litav icr constitilciits I'lMin tlic liiilitcr, wli'ilc a luffiMit taffies almii,' all ilii'sc liiatcrials ami luiiijilcs tliciii in cinit'llsioii, li'ariiijr np dc|)iisits alfi'ady .sc|iarali'd and niixinj;- tlicin to.u;<'tin'i' in their niiLrimil dism-di'i'. Tlir. l'Ul)('KSSl:s n|- sYNTlir.sls I. It MIXl.Ni.. \\'liili'. tlii'i-('roi<'. ditli rriilial ion of scirrcnat ion laki"~ plarc on a snial! scale, and, as Inoad i;eolii.i,'i<'al laeis imiieate. [nolialily on a laiir< scale, on tlie other hand, synthesis of mi\iiit; is also known 1o oecitf in a small \\a\ . and imdotibtedly must someliims allVet lartre li'.asses. Mf. lieckei' sniiiresls tliat molten mairmasnn!si lie minified to some e.lltliesis. Of these, perhaps \\\f simplest and commonest Is silicitii'al ion. alt hoii^ih in many more ev i I'eme I'ases simple sedimentary rocks jire altci'cd into sidiists. or even , lassivo cf.stalline rocks whose characters are indist in'.iiiishal>le 'fom those of similar r.i(dl at r;iiidom. ujll he siillicieiit. yii„lil'tr,iliuti.s ill' inill ;'/r/,-.s. -.\t tile conla<'l of the .Vlliany ;rrairite wilil the scii'ls. - fonniHl into a lij^lil-trray, ;;raniilar rock iiiaiic up mostly of <|iiait/. and nuicli white aixi hi'ow n mica; in this iiirlit-frray rock arc Idack palclics. Moth i^ranitcs am! sciliincntarics arc \-cinc(l liy aplilc. witli while mica, ^Mi'iicls, anil t'lui'TnaliiK', the last arrantred iriapiiically. In the t;rits the altei'alioii is ^'reatcr. Two Inimlred yards IVoni the yranile the re mains lirilliant while mica Hakes with bi'own mica and some tonrmalinc, ami the (|nai-t/ is in lar'jjfc |»ai-t recryslaili/.eil. At pin yards the rock is coarser and rcsemhles a jrindss; there is mndi white mica, nesis of l)laek mii-a, and interveiiiiii; palches of qnart/ with fiarncls ami sillimanite. At the jniu-tion with the <;i'aniie the rock loses all sii:n of clastic (n-ii:in. Miidiiiciiliuiis lit' iiilnisin riii'ks. — (>n the other hand, iuiu'inis rocks themsehes are sometimes modilied liy t he assimilat ion of m.iterials from the u.ill rocks. (J. II. Williams' notes that the most interest inu' point in reirard to the .u'al)ln'os of I li<' Cortlainll district is that they alwavs. so far as oliser\at ion was maile. oc( nr immediate cr\stalline rocks ma\' be formed directiv Irom t liem. I'rof. W. S. r.avlcv ' 1 las described typical ipiartz-kera- tophyres on I'itrcon Toint. Lake Superior, which are probably the result of the fusion of slates and qiiai'l/.ites by intriisi\e jfabbro. Such rocks as these certainlv can not be aceoiinled I'or b\- chemical scirrci^al loll, and we a re i'xtH..nk ..ft liin.v, iili . .lili.iii. |i. :i:.'.V *TIi4' i>ni|)livi' titii'. H«>(liiiM-ntury r<>ii I'niiit. MinnoMitii. iiiitl thi>ir ronta.'t jihi* iiomiiia; Hull. V S. (Ii'dI. Siirvry Nc lim. Isitt I ''^ J GENK.SIS iiK AC.ill KUdl'S i.HIAIilV. \ KINS. 3(1'. I in llli' I'"MI'tyillilt' dikes \M' lia\i' r\ idclii'c imiiilili;: in Midi ;ill iiii:;i|i. Tlii'sf liiU'cs ciiiisisl of I'cick l\ |H's wliii'li all i'li:iii;:i' irriiilually ininiiiu' Hiiiiltici', ami wliicli liavc lifcii iiilriMliici'd al siiccosix c iici'lods. So far iis (IcIfi'iuiiK'il, Ilic carlirst iiilru.^iuiis wcrt' nicks of iidffiiii'tlial*' ciiinixisit inn, wliili' I 111' last wcii' cvl rcnn'ly liasii- and fxti'rincly acid, tlic acid iiilrusiiins liciim' thcxciy laicsi. .Ml ilicse mcks. \arvini,' fl'iini I lie must acid ajilitc to l lie ninst basic inirnlilcndiie or iiyioxcnile, are, liiiwever, esseiit ially coni|io.scd of the same minerals in dill'erent ]iro|iort ions, and these minerals ari'llioseof i;r;inite oi' tri'anudiorite. 'riie observed snccession ot' these inl riisions ajirees with Iddiiiirs's law : wiiiie if the si'histose dikes weie o\erliioked, as they miullt lie in too linrried oliser\ alion, the order would seem to correspond nnircwitli that established in \or\\a.\' and (ireat liritain by UroirL'er and (ieikie, since on l''ortyiiiile ( reek the more acid of the nnsheared dikes always (•III the more basic, and are therefore yoiniirer. The essential result of this is evidence that an original granitic inaf,'ina seems to have .separated into more acid ,-ind more basic portions. co.Nii:Mi'oii.\Ni;oi - i.si m ASK of -ii.n a .wn uatku. In the cr.vslalli/atioii of ijineoiis rocks there is a delinite order in the formal ion of the dill'erent minerals. .Vccordin^r to Iddin^'s,' ordi- naril.N' the oldest mineials are the iron ores, with zircon and ajiatite, wliicli are followed in turn by one or moit> of the ferromau'iiesiaii silicates and the fehlspars, w itii a feldspar and (piartz as the last min- eral to crystalli/.c. in dilVerciil rocks the order varies sli;:lilly, but asarnlethe more basic mineral cr\slalli/.cs out lirst. The order of succession is shown b> the rock st met lire, since the lirst-tormed min- erals lia\(' perfect crystalline form and are often inclosed tiy the later minerals, which are without delinite crystallo,i.'raphic bon:idaiies, but lill interstices left ii\ those alreailv formed. Therefore, in a mau'ina whidi is in the process of consolidation the nioic basic ele- ments crystalli/.c out lirst, and the residual li<|uid porlioii becomes more and more acid w illi the pinnressive .soliditicalioii of the luisic coii- stitiieiits. If, moreover, the partial solidilication is attended by sej;- retratioii. as seems hi;;lily probable, the oriuinal iiiai:nia becomes separated into a solidilied basic portion and a llniil acid |)ortioii. That basic rocks cr\stalli/.e at hi,t;lier temperal mes than acid ones is shown by their contact phenomena. Cases of the altei^ation of the country rock of a dike or otiier iiilriisivc body by actual heat, pro- (iiicin;; bakintr. meltiiijr, cokini;, and I'alcinat ion, are chielly conlined to basic rocks; thechaiiy;e is shown to a less extent by intermediate rocks, and iiexcr b,\ acid ones, such as e;raiiite.' .Ml rocks contain water, partly in chemical combination and partly as inclusions, asshoun b\ microscopic study ami by eh ical anal,\- sis. The niolteii materials, howi'ver, contain much more water than 'III, |li.'.T.vslulli/.«li..uof iuii 1-r ..li- '-ill t'l.ib,-.. S..,- WiHiiii^t v..: .\1. \< M. ■'Oi'lklo. Ti'Xt-B.>ikiif t)i'Ol.,«v.:M .■.llli. mi. pp .ViT.iUii. ^ ( ,'{10 (;i:()I.i)(lV OK THE YUKON fiOl.I) DISTKICT, ALASKA. Ilic icsiili iiiu idik: iJKisl uf iliis Wilier is ('.\|»'I1(m1 al tlif iikhih'iii df siilidilic-alinii, In^rctlicf witli ci'i'laiii prases ami a jricat \ arifl v of iitlicr iiiatcr'ials lii'ld in sohiiiiiii.' In the siirraci' lava this escaping' wattT t'lnins Ilic clomis of sicani. Iiiirlilv <'harfjr<'Mts. and I'ninardlcs; lint wlicn rocks solidily livlow ilic snrl'aci' Ilic c\|n'ilcd waters arc forced into tlic iiiclosinfr roi'k and liml llicir way aloiij,' \vlialc\ cr elianncis olTcr pass- a;;c.- 'I'licsc iindciii:roiiiid waters, licinj; nndcr ^neat |iressnre and intensely licalcont in the rocks into which tlicst' waters find their way, and it is to tlicm that most of the cll'eclsof contact mctamorphisni arc due. Thcaltera- tion of wall rocks liy li<'at alone is. as stat(>d. conlineil to the liasic lntrnsi\cs, and e\eii then docs not cMcikI lii'yond a /.one \aryinj; in width from a few inches to a few feel. INTACT I'nKNoMKN \ A< ll> Uoi Ks i On the other hand, contact metamorphism evidently due to jicrim'- atinii solutions is xcry common and widespread. It is often the ease that rock in conia<'i with intrusive liodies is altered in broad zones, which in c\l reme I'ascs arc several miles in width. The alteral ion is show II lpy I he rcairan^emenl and reerystalli/al ion of materials alrcaily in the rock, ami liy I he int rod net ion of new (dements and I he a I tst lac- t ion of old ones, so t hat the mincraloi^ical and <'hemical nat tire ol' the ro(dv is often ciil irely cliaiiycd - limestoni's Ihm'oimc altered to clicrl. and saiidstoiM's and shales ma\' he I ransformed into perfect ly crystal- line schists. That this iiietamorphisin is ,iciM)mplishc^i<>Krapliy i.f thf lI'M-k-niakiiik' Miri.ral'-, Miliit^'.,'.. I i-ali^^lution. ■M .■iUti..n. .Ni'W York, l.^-ll. p. IM. si'iHn.] i.r.NK.sis u|- Ari;irKi;ors (,if\i;r/. vki\s. 311 This I'dnii 111' cdiiliM'! iiic>l,-iiiiiir|ilii>iM, iliir in |iitiiii;ii ini;- walrrs cdn- lainilii;' wise-. Mini iiiiiicr.'ils in sdliuiuii. In I'liicHv i-cpnlliifil In llii' jifiii I'ucks, lii'iiii:' csiicciiilly riMiuirkalilc iii'diiinl iiii niNi\ c> iii:i>m'> nt' yi-anilc. It siM'iiis imiliiillitcilly t i-iii'. llii'i-i'l'ipi-f, lli;il till' iiiiihcii inalcii:il fiuiii wliicli irraiiilc s(iliilirn'> c-(iiiiaiiis laiin^ walci' lliaii Ilir ha-ii- inauaia^. . ItV-T \l.l,l/, V II. iN 1. 1 c, ISAM IK. Tliis I'oiiclnsiiin is riiirnlKiiatcil liy ilic pioi'iii-i. in iiraiiiii- nl' imt- liliii niiliiM'iils, siirli as iraili>liliiti', ni-l iiilr. ami allaiiilc uliidi alliT tlicii' pliysical cliaiaclcrs al mk-Ii a >li^lil ilfi:i' il ilry lii'al llial it is fVidcnl lliry can ihiI lia\c lii-cii rmiiH'd liy (■(iiiliiii; rnnii rn^iuii, \\liilc it lias Im'cii |ir(i\ci| thai Ihry imild liavr I'nriiicil in Ilic |i|(-.imii-c nf water. It is only liy sii|i|icisiiiy; that uatiT is pri'si'iit in liic'-r acid iiiairinas, ni<>rcii\ cr. that tin' nriliT ol' ci-ystalii/al imi in ui'anilc ami (illiiT rmdvs can lie c\|ilaili cd. Inr 1 lii^ nidci- is liy iin means dc pi 'mien t upiin relat i\ e I'lisiliiliiy. ' I I!V-I\I.I.I/.aT|iin 111 I'Ki.MATITr. In llie pnieess (if c| i ll'eieiit iai iiiii ( ii' setiici.'al inn. I lieiel'ore. we may liclieve that by the pni^ressixe sepaialimi ami cnnsdlidal inn nf the ninre liasi illslitUellls the lesidli.il pnri inn In lues prn;; li'ssi \ I'lv imire acid and iimre ai|inMiiis. 'i'lie e\ idini-e nl' tins in the ease nf JJfrallilc lias just been desiTilied. I'assjni; Irniii ^ramies In 1 111' next ruid< ill the scale i>( ai'idily, pcyniatite Iwhieli. as deserihed. t're- (lUenily Inrins a perfect Iransiiinii lieiweeii ^rraniie and ipiart/ \eiiis) hears si rikili;;' e\ ideii f llie presence nf aliiimlani water. Tlic'se pc^iiialites are nftcii fniiiid ill iiarrnw diUcdcts w liiidi arc pcrsisicnl fur Iniii;- clistaiiccs, and e\ fii in isnlalcd ii'iises in the schists nf cniilaci /.niies, thisc lenses h.i\ iiii;- iin enmmiinicat inn with t lie iri'aiiitic Imdy which has prndiiced the melamniphisiii, allliniiuh they neciir in the vicinity of that Imdv. In these ci-es, eNpeciall.\ in the latter case, the material frnin which the pe;:niaiitcs wen- fnrmed iiiiist lia\e liecii L;rcath alteiinatcd in nlcier In lra\ersc the scjiists in the aliseiiec nf well-deli I lisslires and liiiall> In depnsit the pe-iiiatile ill favnralilc (ipi'llinns. ,\tlelinal inn nf the llllid which has prndlWeil pe;;inatitc is also slinwii by Iheeslrcine frcednm nf eirciilat inn wliich must have prc\ ailed In permit it\ sialli/al inn nn s,, la r.^e a scale as we liml it, fnr ber\ls a sard in diameter and spndiiimMies and feldspars nver :iii feet ill leli;;tll lia\ e ill e\liel ases I n prndiiced. Man\ n{' the peculiar minerals charai'terist ic »( the /niies nf emit act melamnrpliisiii ill the vicinity nf manite are also fniiiid abiindanl l.\ in peumai ites. such as tniirmaline. lev> fre.pn>iil ly c,is>iierile. ,iiid niaii.x mlierrare minerals. 'liclkl.-. Test RiKil( of ( hvv M .•.llli.ni. r- ■»" ■'li II Wiiiiuni-, i'iit..'iitii .\Mii i(.|.t. r s diM,' siii-\.A i-ii."i p ii;i>. = Croslj} uii.l Fiillii- .\iii i|.'nl..Ki-.t .Miirih. IMiI. p i-il ? o II ■i ' 1 -'* J i .; I'^^j W ' . 't «n ;Ul' (ii;ui,oiiv OK Tin: vikon cki.d disi'kh t. alaska. iiniN 111' 1 i:ui.\iN sHAur/. \ i:ins iiialh . I III' iic'^iiijil II H' I'lM- i\ till' ili>ii|i|ic,ii;iiicr III' I'cliisiiMi- .iliil liiu-a. iriMi into |iurf iiiiailz vriiis wliicli s llllW II liMP St I'licl lire (siller tlicy iiciicl rail' In ilif iiiii>t iiiiiiiitc crcx ices and ('.\hil)it I'rc- iiuclit hainliii;,' anil cniiili sti'iii'l lire) llial tlu'V lia\i' 1 n (1c|)(isilcil from soliiliiiiis mi attciiiialril llial llicy may Im'nI Im' (icscrilit'd as waters liiylily liealed and heavily eliai-;red willi mineral mailer in soiiiliitn. '{"iierefiii'c a emn|ilele series of nicks lil»(> tlial wiiicii we liave on Kurlyniile ( reek, ranirin;; frniii iillraliasie rucks, eimsisl inj; cssenlially of inelallie and rerroma;;nesian minerals, In pure (|iiarl/ \eins, may !)(' conceived to liave formed li\' a iirocess of dill'erent 'al ion or seiirp- a ifat ion, tlie cr\stallizali'. llie basic |ioi'lliins lca\in;;' tile residne snccessi\el\ iiioiH siliceous and more ai|iieons, mil 11 al I lii' liiial stai^c lliis residiK' is lil'le moretliaii hot siliceous waler, wliicii contains, liesides silica, small c|iianlilies of many other rock elemeiils wiiich haxe iioi lieeii lake i u|i liy the rock-forniinii: minerals. s(iiH( :■. i)V (idi.j) IN i.nAin/. \i:iNs. liiii.n IN loM-.ois liocKs. This boinjr considcri'd llic orifiin of ([narl/ veins (siicli as tliose of the l'"orlymile district) \xliieh have evident connection witli ;;ranitie or otiicr iuneo'is hollies, we may next iminii'e into tlic source of the tfold which l]ie.\ contain. Tlial ;told and other minei'als found in tlie veins are jn'csent very comnioiily, thonirh in small i|nantities, in ij;ne- ons rocks, esiiecially in dark-coloreil silicates, sncli as liioiiie, hom- lilende, and olivine, has lieeii shown liy tlie chemical resear<-h of ."^anillierjicr. ' Mr. S. !•". iMnnions- has directed a seriesof careful lesls of selected iffncons rocks from dilTeieiit localities in Cnster Connty, Colorado, with a \ iew to determining^ their melalli inlcnis. Fixe onl of the nine rocks tested contained a|ipreeiatile ainonnis of sil\(>r, and In one of these liotli siherand lead were fonnd in eomhinalioii wil li ol her liases in the I li silicates. These rocks wei'e ti'achvh ilio-ile rlivolite, and ililTerent \ ariet ies of ''ranile from dilVereiil iocalilie; I'rof. (;. 1'. .Merrill' has deseiihed an occurrence o f fi' ee i;old in jiranile, whicii he jiid;;es to lie orininal. The ,u:old occurs associated with th a or wholly emlieddeil in the crystals of (|iiai'tz or feld spar. I'rofessor .Merrill also notes thai W. Moricke has descrilied free iii)U\. which he repir'ded as an oriy;inal constitnenl, in a niuwi/,- trai'li.vle from ( liile.' ' rntt'r-turlmntffn UImt Er/.j;llii^ft'. IH-s:,*. ■'S.'Vi'iitiviitli Ami Hi'pi r S (Ji'ipI Survey. Pint II. iHim. p. am. ».\Mi, .lour. S,'i . .\pi-il, IHiiii, nil «,.ri,.H. Vol. I. p. ;iiili. < W Miii'i.'lio. Twlifnimks ihjn.'iiil .Mittli.'il . III. \XVL •ii II ■^ MTHir] (iKNESis uK Ari!ii-i;ii(irs (,>i akiz \i;ins. 3i;{ .MlNKKAl.iH.lcM, lli:i.MMN~ ..|' ITi.M \TrnS AMi i,.|.\|ll/ \1;|N, |.. l.jSKulS Itnc Ks l\ OKM-.H \]., Ill |)fi,'iiiiil ili'> .-iri' t'diiiiil iiM iiiiiisiiiil iiiiiiilici- 111' rail' Mini wcll- (•r_\ st.-illi/cil iiiinciaU. In'sidi-s ilii' (•ciiiiiiicnicr ^|)l■(•i(•^. A >iii(l\ df llicsi" iiiiiMTals sIkiws llial llii' lliiiil Irmii wliicli |ifLrinal ili' lias roiisoli- (liilfil iMiiiiainc IpcI'chi' slah'il, iiiiisl lia\i' lircii j;rcall\ allciiiialcil, ami In I liis allciiiial inn llir M-jriciral ion nj' widely (lilVcrcnl iiiiiii'ials in (iill'ii-riil pails nl' llic |iciriiiiilic lioily may In- ascrilird, for ii has |M'iiiiilicd aliiiiidant ciiciilai ion. and llicii'hy pro- motcil llii' conci'iii lal ion of nnUiTials orij;inall,\' dissciiiiiiaicd in iiiiniitt' (piaiitilics I liioii^lioiit. Passing I'roiii |M'i,niial ilcs ioi|iiail/. \«'iiis. \\f liml ihai alllionijli ijio ntiici' iiiiiicrals Im'ciihic i;iTatl.\ siihoiiliiialc in i|uaiilil.\' lo (piarlz, .\<'t of tiiosi- wliicli do occur llicrc is an c\i raordiiiar.\' variety. iU'iii'y Louis'- lias compiled a lisl of no fewer iliaii 77 mineral species, inau.v of tlu'lii rare, occiirriiii;- in auriferous i|iiailz \eiiis. .Mr. (J. K. Meeker ' has made oiil a lisl of lii' iiiiiieials which occur in llie aurifei'- ons (piai't/ \ eiiisof llie soiiihern .Vppalaciiians. 'I'liese spei-ies include loiM'maline, cassiterile, lliiorile. and other minerals which are rare, and which are also ehaiaeterisi ic of pei^inalile and of the eonlaci /.ones around acid ill! i'usi\e 1 ks. it is found also that nuiscovite, liiotile. and ori hoidase occur occasionally as (laii of tiie iraiifriu' of <;ol(l-. ilT.'i. ('ri»ili>- iiiid FuUi'r. Am. (J.M,l,,t;i>t. v.. I. XI.V.N'ii :i, p l.vi. ■'MiiiiTiilnijiial .Mii«., Xiiv.. IKltl. 11 :Jll 'Sixti'i'lilh .Villi Ki'pt. L'. S. liv.il. Siiivi'). Part III. tv.i.-i.ip. r.i. >i ip. lit . p -'Hi •lip I'lt., p. •»!. \% ii- -f r L'tii ;'.14 (jr.Ol.odV OK TlIK YUKON DISTRICT, ALASKA. m III tin- AlilNlviiii veins no opiiort unit ifs ll' ( ONCKNI'liA rio\ (iK <;iiiJ>. In <|iiarl/. veins as a whole, therefore, we appear to have, lioides siliea, most other elements in small c[iiaiilities, ineliidinu ^rohl. It has already lieeii siijijrested that the Alaskan veins, wliieliare so intimately eonneeteil with aeid ilit riisi\e rocks, have lieeii deposited from the residual lliiiil left hy the crystallization of these rocks. We may there- for iieei\e that the water expelled from the <'ryslalli/iii<,' jrranite or a pi it e eontaineij cli icily silica, and also jrold and many othi'r eli'iiieiits, in solution. .Ml those eleiiieiits were prolialily \'ery nnil'oriiily ami miniitcdy disseminated ill t he residual lliiid, as they are in the iniieons ro<'ks. W.iter discharged from coolintc rocks is hi;;hly lieateil.ami in these jiranites ami aplites, which liave soliditied at a consideralde deptli lielow tile surface, the e.\|ielled waters must also ha\e heeil under fjireat. pressure, so thai, the solvent power was vastly increased, allhou^di the circulation was not f,'reatly impeded ihereliy. This residual Iliiid is prob.-ihly of a chemical idiaracter especially Well suited for lioldin;; ;;ol. (iold is soliilile ill many of the ciaiimoncr salts;' and it has hceii [loinled out liy \arioiis writers that silica and ^old may often pass into these solutions and he deposited from them under the same con- ditions.^ In the preoipitalioii of the pdd it is prolialile thai pyrite 'Frc'iiiy. i;niyilojuiliiMliiiii|(|iii', Tiiino III, III'' culiiir. |p i:i ■' Itr. (i. K. Hi'cki T. Si.xti-i'iilli .\iin. Hfpt I'. S. (ir.il Survfj. I'lirt IN. IMri.p :;.•,»< Dr T I". Egli'Hton. Trull". Am Ins. Min. liiiK . Vol. l.\. p liWutsfii. V GENESIS (IF AlKllEliOrS (.if AKT/ \ KINS. 31.-) and olli.'i' siilpliiiics jili'i'iidy funned ;iic iiM|)ciil;ini ImcIuis. < M' all till' iiK'tidiic iiiiiiciiils with wjiicli jrnld is associated in i|iiai'tz veins, iron ii\ rile is most alinndanl, and ils presenee seems td he in a liiiilled way indicat i\ e ol' the lieluiess of liie \ clii. Mie;nse(i]iie exainiiial idiis of tins pyrile j^eiierally show iiielallie jrold, which has been deposited sometimes tiiion th(> pyrites, sometimes simnltaneonsly with it; aiLil in the laboratoi'y it. lias been shown that pyi'ile is ono of the best pre- eipitants of jjold from solution. Often, howevei-, the ityi'ite of ipiai'tz veins is not iissoeiafetl wilji jjold, and. on the other hand, ^old fre- (jnently oemirs isolatecl in the (pnirtz ami is |)ure, except foi' conlain- int; small proportions of sihcr and ot her metals. In this latter case the Jiold must have been precipitatetl l)y other moans, proliably often .simply by elianjre of temperature oi' pressure. ^ ()i'.si;i£\ I'.ii ((i.\NK( I i(is di' (.(ii,ii-(,ir AUt/. \i;iss w i di i\ii;i -^ixk micKs. Tile conneelion of auriferous quart/ \ ejus with intrusive iniieous rocks, especially diorite and frraiiile, has loiifj lieeii known. In Aus- tralia tile ;;old-(piart/. veins, in cerlaiii localities at least, ociMir ;it the contael of diorite ami schists, and in I he I'rals the preseii )!' u:old depends ii[)on llu currence of eru|)tive rocks and tectonic ritisli Columbia, on a jiarl of the ^■ukon jjold belt. Dr. (i. M. D.iusoii ' found evidence to show lliat the developm( is also an iiiereasini; proportion of water over other materials, this water beinj,' ill all eases ill a liifrli state of union witli the other ' K. vim Krmitz, Am. (IiMil.i^lst, Vol. XVIII. Xi>. :.'. p. 1"T •' A\irifc.r..u» (ii-iiv.'U of th.' Si.-i-ni Xi'viiilii, ii ;l.Vl ".Villi, liopt. Uu.il. Milt. Hist Sm-vi'.v I'linuilH. V.il. III. part I. \i ;l"iB Hi'. V ■ if & M' Mid (iKul.OOY OK THE YUKON (iOl.l) DISTIUCT, ALASKA. iiiatfrials.so Imifi as tlicsc mate rials ai'i' iinsolidilii'il ; lli is slate of nil ion may lio I'lthcr clK'niical or iiliysical. In lln' liiial rcsiihn- tin' (liiid bfciniit's su ai|iii'niis anil s(i siliccinis I hat it passes with im sharp (li vi- sion line into lii^rlily heateil, siliceous waters, which contain also small ainuiiiitsor niosi of the other rock-t';hly a(|iieons residue, Iiowover, the fluid hccoiiies so attenuated that circulation liecomcs very free, and concentration of the rarer elements is periiiitlcd; so the jjold is .sej^re^rated, often into pockets of considerable si/e; and in a like manner other materials are concentrated, generally i dependent of the concenlration of the ;;i)ld. It isalso prolialile that i ne residual solution is, owiiijr to jiliysical or chemii-al conditions, or Itotli, especi- ally adapted to the retention of ji'old, and tliprefore is relatively rii'her in this metal than ordinary nietallifc rons solutions, and possi- bly more so than the molten iiiai,'nias out of which the igneous rocks solidilied. This theory is not intended lo apply to the occurreiii'o of gold in any other form than in the typical gokl-qiiarlz veins. liJii iii •1 ,'i*'^ -m M 'Ill b mi /' C- *»V1, INTER NAT 10 NALVjv=t, r boundary' ^^ II' ■^Ji^ BR_ITJI_SH_AM ERICA ALASKA 00 < w « o o o Hi ■I , r II A I' IK I! \l 1M,\< I.I! i>i:i'o>ri>. 'i'liroiiirlKiiil iK'iii'ly tlif wjiolc oi' Ai!t>k,i i^'ulil is fmmii dissonil- llillci ill Itll* (li'tlilllS wllicli li;is lii'i'll ilriiM'il ficilll the il lilM-'ii HM it' llic solid rucks, oi'li'ii it is in siicli miiiiII iiimniiii tliiil it imii ikpI lie Iti'ofitiiltly cxli'ai'tcil, 1ml sinndiiiH's it is ciincciiir.iii'il |p\ umIit Mdinii ill sucli (li'}j;r( iis 111 in\ itc iiiiiiiiii;. 'I'lius Till- till' |iiiiliinlilt' ili'|Hi'-i liiiM' all liccn I'cimiil in or niar llii' linis of the pirsi'iil >lriMiii> 'I'iu'sc iccrMi ;. ;avfls iiia\' lie ili\ idcil into two rliicl' I'li In till' larj^cr streams aciMiinulatioiis of ;rra\i'l are niaili' in |)lari'>. ot' slai'k- riiiiiii I'urri'iil, sncli as tlii' iiiin-r or coiirav i' siili'sul' imum's. 'riii>-r ai'ciiniM latioi IS art' ca lli'il Mill ol'ti'ii I'liiilain niMi'li irolil. ■I'll. oilier oeeiirrei.ee is in tin small siiilelies wliieli I'eeil I lie la rvrer st reams In the holloni of l liese ill IColil, anil as 1 liese ar llie gravels are lrei|iienllv ver> rieh re easil\ worUeil, tlie\ eonstilnteal llie jiresenl li ' time the most importaiil elass ol plaeer ileiiosii GULCH DIGGINGS. hiiUTVMII.K IHVllllt T. The Fortyniile jilaeer minii lisiriet iiielinles sonii ''llll'lles wliieli lllo Sixtviiiile Creek, sueli a- .Mi ler ami run into Fortymile Creek, ami s wliieli run into SiMymile (reek. Throufih lliis (lisiriet the inteiii.itional lioundjiry runs, dividiiiy: it so tlial the fiiilehes uhieh How ii (ilaeier, are in I'.ritisli territory, while the iifeater part of the ilistriet is Anicriean. I'l. \\.\ is .-i ma|) of I'mlymile Creek and vieinilyso far as is known. This map is from skelehes iiuide by the (Jeolo^neal Siirv<'y party iiiider the direetimi of the writer, with the exeepiion of that |iortion i hoiiiidary am if Fortyniile Creek whiell lies helweeli the inleriialioiia I the Yukon, whieh is taken from a survey by the I'liiied veil, is indi- StatesCoast Survey. The topo^n-aphy. so I'aras wasohsei caled on this map hy contours at intervals of ."ii'" feel. The position of this district in relation to the rest of the Viiknii pild hell is iiidi- 1 on tilt' p-neral mapof the 'lull ..r all .'M-i «.--i I r.Mi.iliiLr am i.-liiii'. till' a\iN I.I wliii-li - ill ;.'i'ii.ial |iaiallil 1.. I lit' main I ii'ImI ..I' I-.. it \ 111 lii- ( I'lM'k, iiinl at mil' | la.i' 1 in.- almii,' lln' >li\ iili' Ih-Ivm'i'Ii t Ih' >i \t \ in lie mimI I'liil \ iiiin' watri - M.'i.L' t III- a\i- i- i'\|iiimm| a liasal -rlii^lu-t' Uiaiiiti . airi .>ii III"' 'I.iaU- "I tli.' t'.il.l ai.' i|nali.'lti'--i-liisl- lii'lniiLrinir In tin- lliii'li (ii'i'i. -1 lii'-; ami ah'iM- iIum'. inaiMi'. i| ilarl/iti' -.-lii-l -, itliil III. in- liit;lil.\ iiii'l ■•ni.>i|>li>i-i'il Inn iilili'inli' ami iiiil-. "Iiii '1 ail' .alli-'i till' l''i>rl vinili' >.'i I.-- In iln'-i' inrk- aii- ilik.'- nl' all kiniU, Miini-l iiiir- In •_''ii'at aldin.lan.'.-. .'-lii'iMallN ..n 1 In- >.nii h I'.iiU ..t' I''.i|-1 \ • mill' Ci'ii'U I tii till' ii|i|ii'f pari ..f tl..' Sinilji {''ml,, in tin' \ ii'inilv nf iliii'ki'ii ami Na|»>li'i>ii riirk-. ai >' Lrici'ii tiilYsaml slates lii'luiiLrilif^ l"liel I re il'esellts the ;;eiiliiir\ In the re;;iiill nf .Miller, 'ihieil'l". i'lik.'l . ami ' »a\ is ei-eeks, 1 he l''iil 1. Villi le-Si My 1 ' le lii viile. amlapnl'- I'nn ..I' llie mam r.irlyniile < I'ei k. < Iii llii- inip the y;ii|eli ;ri'avels aiel il,.' I'l I'l- !:ra\ .1- are .list iir_'iiislii'i| 1>\ -eparate eulnrs. The ;;iileh •_ia\i'i- ar.' eniil iiiii..;;-. I'.ir lhe,\ are ilireelly inaile up .il' tain- t'riiiii thesliep sinpes. wliieli the sinali supply nl water ill the j^lllelie- is illsllHieiellt tnreinnxe. They are eVel'N where preselM. Ill the lliaill e'eek. I'liWeMr, ale la I'L,'!' sll ppl i"- nf » a 1 1 r. Ill lliall.\ plaee- -llfticiellt III keep t he I'lianiie' I'lee rrnlii aei'llllll'j.ll lulls, ami niil> ill reiiinlisuf slaek eiirreiit ill. . i\i'l aeeiiniiilai ill's. Ill' liar-, i'min. rherernre mi the map the ri\ei';.'i'a\ el.s aie li:'-|ill\ represeiileil a- lieiii^ intermit telil . Ill this map the ;jraiiitii' avis nf ilie I'nrt \ mile ant ieliiie is stiii«ii. I anki'il nil linl h -Lies ll\ I he Hi nil ( leek >.illi-ls. « hieh are sill 'I'vei led nlhe iinrthaml In the smith l>\ the I ks 111 the l''iirtyniile .series. 'n the i|..rill\\i'stci 11 part <>( the map Ireiplellt dikes are seen ellllin^t l.ie sehisls 'I'liese dik'- ale nf .1 '.^nal Nam t\ nf riiek. as already ■J I Kt^ 47 • r. n 7. — / 1^ < i V. ^'5 ,-H < !< X ■■N2 s t ui < o 4 U 1 ■*■ ' 4 y I z: ' o o tij 'A jiri f! (in (II M(i(;i.Ni,*: riiKMMIII MSIKIil. 3l'.t I'llllv (ll'MTilMMl. lull llli- iJill'iTilll l\|i L:i'ii liiM'ii ihiiiiclii lii'-i I .iii:;>- nil.. ..ii.. .111..1 her ml I>ilii-ii liiili. 'I'll.. ililVi.H'iil ii^c- .if llii' iliki-s. liiiwi'vi':. :iii.| till' nialilD'l' ill \N liirli llii'\ i-iil .1111- ,111. illi.-i. .Ill- iiiilic'.ili.l li\ lii.'ir .'HI liii..N SllCCl J ll'|l|l.S|-|| I- .III aiiM 1\ in:: jii-i vm'^i ..i ili.n -Iniuii .m shfct l.,iiicl iiiiii|iii^i.> I'oi'l \ mill- 1 11... k ,il"\i. (•'Kiicii ( ic. k. till- >ciiii|i h'nrk III' l-'iiil,\ iiiilf, Miiil I'lMiikiiii .'iiiil ,\ii|Mi|iuii .iiik", uiili tl,, lii'iiil III' ( liii-ki.|i t ii-.'k I'll llii» »liiil ilii. L'ulili .iiiil lllil 11 \ IT 'JWiK I lllr illilii'illi'il .1* nil .-I I I !ll I his i-i'iriiiN tin "i-.l|.||\ |iil<'li Ml' l||i. I'lill \ mill' iiMl il'iilli. IliC a|l|).lll'lll 1\ I'Mllll'il I 111. :;l;|llil|. |.\|iii-.|.|| lull Ili'T II' siitr.ii'i.. il> |ih Iii'ili;; »l aliiin: till' axis 111' ihis I'nlil Ih'Mi'miIi iI laki'ii liN llii' lliii'li t ii'i'k >i'lii>l> .'iinl III I III' ii.ii'ili ,iimI 111 til nitli (>( till' liiii'li ( ii'i'k •.I'lii^l-. lie I III. nii'ks .il till' I'liitx :iiili' '.I'lii'N I'll |\l> 111' till' I'lllll ,'lt llli- iMlilll, liiAM'M'i. i- iii'i'U|iii'ii li\ a i;ii'at |ir I'li-imi III' iliki's. Miiiit' 111' iinniriiM' -i/i'. ami llii'-r liavi- •1iiiil iiii'. ainl i'\i'ii Ilit'ii' 11a I nil', i- II. It al«a> N iiilaiii l.iki' I In' .liki'- -Imu ii mi >lii'i't I , IIh'm- ari. Ill' all \ aiii'l ii'>, I'liuii i'\l ri'iiii'l\ .iriil t.. I'Mii'iii •!) Iia-ii'i >i'l lirrt'. alsii. mi I'l.i— ijliral inn lia- Im'cii ,illi.iii|ili'i|. -a'l i' that ;;i\i'M in tin' el la I it I 'I' nil iitiii'iiiis I'm- ks, ami t lirv lia\ i' lii'i'ii iiia|i|ii'il nmli'r mi ilm. IIh' ijid'lTI'l Ill ayi' ln'in.' ■.Iiiiuii li\ lliiii' iiiilliiii". I Ml ( liii'ki'ii Cn-ck, ami mi I'mlymiii' ( ii'i'k .iIimM' i'riinklin li.'ili's nl' tin' Ml'^simi ( ii'ck si'i'ii'N. I'iii;ill\ |iali'lii's 111' Ti'il iar> liasalt .in' I'miiiil mi Na|iiili'nn ami < liii-kfii i-ii'i'k- .iml an' i'i'|in'>i'iiti'il nil I 111' ina|i. .\i'«'iiin|iaiiniii; iIh'-i' Iwn l'i'hIii'-Mi'.iI 111.111- aii' rmiLili ii.is- -iTiimi- I'lUisI nii'Ifd .111 an i'\ai;y:i'i'ali'ii vitIh a! m'.iIi'. .iihI inti'iiiliil in iniivi'V an iilca nl' llii' L'l'in'i'al -t iiii't nn'. alllmiiLili nn |iii.|i.nsimis In ai'i'iliafv 111' ili'lail ail' iiiaili'. In tin' i-ni— -I'll imi ai'i'iiiii|ian\ inu -In-i'l I tin- l''iirt \ mill' aniii'liiii' iv -linvvii. .111 ■aMilll.ll illkl's. .■Ilttiim till' M'lli- loM- I'lirks. Ill till' M'i.|inii acriiliilian.N inj; slii'i't J I hi' -.iiiii' aiil ii'liiK' is sct'ii, lull till- iiii'ks aliiliy: ilN axi-^ an' niili'h ili-lmtril li\ lln'i^rn-at aliuml.iiiii' 111' ii;iii'mi> intin-imis \i tin. Ii'li nl' tin' -.•ciimi lln' ltaiii|iai't M'i'ir- ami iIh' niiinnrnfitialilx .i\ i'il\ iiil; Mi-— mn < icrk si.|ii"> ail' n'|ii'<'M'iili.i| ni -. iiii'i |. .\ . .1 ..I I . ill -. Till' ilitl'i'ii'iit -nlihi's III till' Inilyniili' ijisliiil whiih lia\i' |ini (lili'i'ii plai'iT ynlil ill inilalili' aiiiniinl «ill im" lir iji'si'iilii'il in ili'lail (HI hi'-c i|rsi.|'i|il i.i|i> I III' ii'|iiil I- nil Milli'l- .'llnl ( hii'ki'll rli'i'ks an- li,\ I'liki'i', l>a\ Is. .inil I'f.inklin mi.i'ks li\ II W ,1. K. Spiiir; lliiiM' (niiiiliirli ; ami llinsi .III (ll.ii'ii'i ami N.-iiinlinii in •Scliiaili'i. ■ks liv 1 ( !«" ijj 2i> (ii;(»i.()(iY di' Till-; viisON (;<>i.i) i)|>iui(:t, Alaska. MrM.>:H • iir.r.K .MIIlf|-( I U llils |il'i>l);illly Im'I'II till- llliisl |)lil.I lirl. ;iiii| lie* ill I 111' iiiiiiKMliatc \ iriiiil y iif ni Iht triililio uliicli liii\r lifcii iiiiliilily inipiliH't Im', siicIi as (ilacicr, I'likcr, lliPW illlii !• pail 111' il I);i •ii'i-ks. Till' uali'i's 111' MilliT aini (ilariiT I'liM'k ■M'avalril llii-ir ili'r|i \ allry-. ill lali' Si\l\iiiili' C'ri'i'k. uliili' lliusripf I'likiT ami l)a\ is itim-Us ai llic lirailwali'is 111' i'liityiiiilf ( rcrk. 'I'lu' iliaiiiatri' areas nl' Sj\l \ mili' aiiil i'mlyiiiili' iTi'i'ks an« si'pai'alcd liy a liil^rc of iiunlrralt' JH'ijrlii. wliiiM' tii|i is i-iiiiiparativi'ly llat ami I'liriiis part nl' tin- u'l'Mrral plali'aii ill w liirli I 111' si ii'jiiiis lia li)i.rii'al t iiiii'. M illiT ( ri'i'k was lirsi pmspi'i'li'il inn lialrly aliiT I lir lirsl ilisi'nv - i-\\ nt'y:ip|i| ill Iliis ii';;iiiii, w'lii'li was aliipiil |ss7, mi p'raiikliii (iiilrli. A I'l'W years itisn il was llie liiisicsl spiil nli llie Ippcr ^ iikiili, liiil al piisi'iil I III' rii'lii'sl iii::niii;:s liaxe liccii larjri'ly wiirki'il ipiil.ainl llii' iii'u iliM'ip\ I'lii's ill I III' liiri'li ( ri'ik ilisi rid ami rlsi'W ln'ii- lia\ i' ilraw ii iilV iiiipsl III' ilii' iiiiiiiiiLr popiilal iiiii. Ill llii' .viiiii'r nl' ls;i.".-'.ir, i||,.|'i' will' a 111 III I ."pill I iiiiiiiTs ill I li s \ ii'iiiily. iiinsl ly mi M illm- ( ri'ik, liiil in llic spriiij: iiim-i' than lialT'if llial iiiiiiilicr li'll Inr llir xaiiniisly eslinialeil al s.'Iii.iumi in .s;,! i.iinii ;,s llie resiili nl' llie wiirk ><\' r.Mp w iiili'is ami niie Minimi r. I )iiriiiL;' I liis lime lie eniplnv eil mi an axcraire alimil s men, at limes as many as |s. payiiiu' lliem n|ii a ilay in siiiiimer ami smiiewlial less in wiaier. In this as In nilur cases it InnU smile lime In yi I t lie el aim reaily Inr wnrkillU' lie In re any iriilil was aet iiall.N prmliieed, sn I hat il was ael iially wnrkeil I'miryears ill all. Willi llie |iriilit alin\(' staleil. 'I'liis prnlil Is. linwe\er, exeep- tiiiiial, ami allliniif,'li several nllnr men lia\e left Milli'i- ( reek with "stakes" 111' xo.niiii III' .sl.Miu. yet many iimre have iiiaile mih "ua^cs" — llial is, *|na day and smiie dn mil make lliat. Sjiii/ii (if rtilli I/. 'I'lie leli),;lll nl' Miller { reek I'lom its jmii'linli wit li Sixty .Mile (rei'k isalmul iil miles, and ilsemirse i^^ nearly slrai^ilil. Tlie frradieiil nf ils lied is ei nsidi'ialile. as is the ease with all nlher streams '.■< this rej;inii. .iiid this j,n'adieiil iiiereases sli<{lilly Inward llie head 111' I he e reek. .\l the extreme liead I lie slope lieenmes \ cry slei'|i, iliealiirle iiearl.\ enriispmidin^r w ilh thai nl' the sides "t' tlii'\alle\ t'artlli'i' dip>\ II. Ill Ueneral the Vllllliy l.s V shaped. Iiiil ,il tin head it widens, iinl slldWH a lelldelle\ In assume a linile clirved, or U-'^li"l»''l> 'illllille ill eross-seclinn, thus sliy^jest iiiK H (jlneiill Mllllllllf ||ei|li'r nr einpie. Il is indeed piiilmlil.V lo h'O iietinn that tills lintailclliii;.' and llalteiiiiiu isdile ill the willlci' lee and simw .lei'iiiiiiiiate and lia\e a leiidi lli'\- ■IM'IIII I ilfl,i M I)Ii.cilN(.-: Mil, I, Kit CULIK. 3-2 1 to move rrcim tin- iliviiliii^; iii|;.'i' iImuh tin- sleep slnpes wliieli llu) rii])iill\ ciiltiii;; .stri'iiiri lias left; mi tli;ii iliiriiiu' till' s|iiiii;.' iiiniillis, W lien the ice is surieliilli,' ilil'l lliell ilii,', llii> I lead ul' llic \ alley i> ncell- pied liy a \ eiilalile t liiiiii.'li small and t ran-ieiit irlaeier. Tlie riinndiiii; if the head •>( I le \alle\' and its ;;radnal alleratinii into ihe luriii u| a rin|iie is due ill ]iail 111 the iiiii\iii:: <>( the ire, lull perhaps iiiiiii« lar^'ely In the erDsimi nl' I he ;rlaeial water-, « hieli .ire di-l rilniled ii\er the \\liiile width 111' Ihe \alle\ in-lead nl liiiiiu emiieni laled in its ImMIi nil, as are the stream- lli.il ha\e nn dependenee nprni lei tlie iee iiudls lineal liirniw - and dilelie- are Inrniid nn the udaeier, and Ihe water llnwini: rrinii these and I'alliim' user the iie ifnnt runiis watell'alls w liieh eliiirn up I he i.'ra\el and carry it duw n t he \ alley, so thai Ihe lied rmdv is nrieii laid hare; and a- Ihe I'lunl nl' the ico recedes this \ijfiiriins erusiun is hrnni^lil In hear npnii -iicces-ively lii;;her parts nl' the\alle\, 'I'hi- aeiinii is nl' ecnnnniie inipnrianei', since it |ire vents aceiimillatinn- nl' ami ten in- ;rra'. el- v\ it hin .ina- in which it, ((]>ei'ales -a facl which ha- lieeii prnsed hy pr i-pi d iiiL:. Tl le lieails III' the nt her l; niche- in I his s ici nil \' -Imw I he -ame tend- ency In develnp an anipliiiheal rical rnriii. (Jlacier ( reek inpariicn- r has a cinine w hii iniich mure sNiiiniel rical than that nl' Mil (reek ■\ plana I inn i- th.il mi d lac ier t feck t In acier IS lar;;e anil llliile persislenl nil accniinl 111' many springs u liicli rnrnish an aliiindanl llnwnl' water I'min nnderi;rnnnd sniirci - and help materially in I he acciimiilal imi n\' ii'c, '{'he sleep sides nl' the Miller (reek \ alley .ire indented li> I'uirnws ifullies, iisnalh' small. 'I'liese are c, i\' I lie miners This term appears In I ia\ e nri;rin iiled in Miller ( reek, and since it has spread all n\ er I he ,i;(ild disi ricls. as a cnnseipien I' I he seal lerin^' nf the Milleri'rcel; miners, it ina\- lie nl' intere-i In mile its deri\ ,tl imi as;,d\en liy an nid miner, Smiie yen- ann a miner li\ ilie name nf Milller. whn irjive his n.illic in the creek. ; (ioi.D disiimct, ai.aska. Ml III' I' ( I'l-ck \'alli'\ \v ill I' Hill ill- c II II' III miili'i'staiiil lid I it 1 Ih' nat iiri> anil illsii'iiiiiliiiii (if I III' ^1 i-rjuii i:i'ii\ I'N III w liii'li i;iilil is rniiiiil, Ni'ai- I III' 111 'ail III' till' \alli'\' I 111' re is a \i'i\ tlilii i'ii\ iTiii;: ut' ili'l lilal iiiali'- I'ial. ami in many jilai'i's tin' Iti'il inrk is laiil lian', m' is liiililiii I'liim tl lisi'i\ I'l' I 111 I \ liy I III' I hick LTiiivN I li 111' muss w liii'li I I'll! Is III i'ii\ I'l- i'V I'lyl liiri^r I liiiiii;,'liiiilt tliis I'liiiiiliy. Al alimil -l iiiilt's I'lmn llii' lii'ail llii'i'i' ari' :i iir I IVi'l nf i:ra\i'ls, ainl laillii'i' iIunmi iIh- I liii'kiii'ss iiii'irasi's, iiniil al ilii' .jiiin-iiiiri wiili Sivlymili' ( ri'i'k il is alimii 1 ■> I'l'i'l. 'i'lii'si' ;:ia\i'ls ail' maili' ii|i nC Hal ri'ay:iiii'iil.s nl' schist ami liiiwliji'i's, exactly like llir mck iiiili'rii|i|iiiiL;' mi llic steep siiles of the valley. These rrauiiiciits sliiiw sume slii;lil «aler act inn. in thai they all lie Mat ami aie si lal ilieil, I in I are \ ei\ little wnril. '{'he leelileness 111' the cnrieiit uliich has aiian;;eil the ile|iiisit issliuwn liy the laci thai inixeil with I he lai';;er I'lairnieiils is ciiiisiilei'.ilile tine ileiiilns, which I he sli'eam has nut lieen si lun^.^ emnmh lu si'|iarate. In the thicker liiaxcls the material is \er\ neai'ly the saitie rriiin tup to Itut- tiiiii, except llial al the tup the materials slmw a lemleiicy In lieeume liner, ami un i he \ eiy snifaee I here is ul'ten a luut ur I \mi uf line suit, with l'e\M'irra;;nii'nls lit' schist. riirull;;li the npperour I feet uftlie Lrra\els. ,ls seen in cllls ni.lile in the prueess III' miniiiL'. Ihere are III ten la M 'IS III' rut I en muss ami wuml alternal inir " it li 1 he ,Lrra\ el, i mil- eat Iiil: lempinary peiimls ul' \ i'y:i'tat inn. The ;rulil lull 111 I is always at the I mi turn ul' I he jrra\ els, « liali'\ ii I he thiekiiess may lie. tiiaM'l which cuntains ^ulil in wurkalile i|iiiiiitily IS technically calleil "jiaN ilin." it is usually nut mure than 'I ur I I'l'i'l thick, anil I'lum this runs iluw n tu a lew inelies ur less. 'I 'he lieil ruck i!se|f,ai t he Jnnet iun with the ura\ el, usually euntains j,'uii|. ami suiiieiiniis pa>s I'lir wurkin;; I'ur .is much as l' ui' ;> reel iluwn. (M'teii this nppermusl /.um' ul' scliisi is lehei' Ihan the frravels. 'I'he ri'opieiil illver.aence liclwecn the chailllei ul' pa.\ illl't ill llie ;;raveK .mil the channel ui present ilraiiiai;i' is suinei imes ilne tu the iiatniial wanderiiiti's ul the sircam I'l'iim siili tu siile. ami partly In I'ui'ceil i'h,>ins;es III' piisiiiuii, such, I'ur example, as may he elVecteil liy lamlslides. N'e.ii 1 he uppei'imisl limit ul pa,v .ltl■HVel^s a lanilsliile has pllsheil Ihe creek lu tile Uurlll, pl'ui|nciH« a sIlLillt lieml. In the pri'S- eiil creek liulliiiii there are unl\' :> ID- I feel 111' triaxels, while the laml- slide in.iieii.'il w lien si rippeil a wa.\' rcM-als 7 ur >• feel i>\' uhler t;ra\ els, which ,'ire alsu .inrileruns. ()\vin;; III the fact that the valley is V-shaped and that I he yrinlienl is snllieieiii lu prcNcnt iiii.v eiinsideralile siltin^iip nl the ii|ipi'i' liurtiun, iheyraM'ls are exlreniely liinited as tu wjillli as vvoll us In ihickniss, the averani width lieiiiir |»liilialil\ nut mure lliaii rtll feet. The lirhest },'ra\el. huweM'i', 'Upies eei'laiii iiari'iiwer •/.unes, (iiio III' III!' I'ii'hesi spills which has been I'unml shuwin^'a pa.v streak mil.v 'll feel w iili". allliiiii^^h it is 11 feel in liiiekiiess. 'I'liis pity sti'oiik isa chan- nel uf ^'I'aM'ls rich III uiilil and Imumled un Imlii sides and un tu|i liy ■■■"'. cfl.i II |ili;(iiN(i-: Mii.i,i;i; i UKKK. 3-.»3 111' luinc'ii iii,ilfii:il. It Miiiicli lii'il III' llii- >lic;iiii MIKJ Miiiicliii \\Vl-<'\ \\ l||ll|l-l- llli' |ll>>-.CIlt 1C> til iilir >i(|r .if II . I» L'lil'l li.i-. mil hi'i'ii I'll' «ni kniu' iiinliT rur mIhiIII Jl lulli'^ :ll llll' MTV Ill'JIcl clI' III.' ( fiiiiliil ill Millii'ii'iil l\ larL'!' .'ii'i'iiiimlii! ioii^ ii> ]irc>cnl (•iiiicliliiui-,. Tiii-. !,icl is cNliliiiiii'il liylhc ^iciilir .iMiMiiiil III' crusiiiii ill Ihi- I II llli nil 111' llll' x.ijjcy, ami I his is clue I III II !>■ Ill llll' sli'i'p slii|ii', wliirii iiirri'jiM's llll' {'iiii'viii;,' |iii\\i'i' ul' ilfaiiia;,'!' waliTs, liiit cliicllv III llll' rlVri'ls III' llll' liiral irlai'iiT. » liii'li lias ln'l'iiri' Imi'm ri'lci ii'd t". A nliii^' 111 ll Iisi'i'val inns ul' iiiiiiits, iIh' rnnil nl' llii' MilliT ( ii'i'k ijlacii'i' ciiiiii'iili's \ I'l'v iH'ailv « il li I lii' ii|iiii'r liiiiii uf |ia\' iriavcl, sliiiw iiiy; I lial llll' iMiiii' \ iiili'iil ai'iimi ul' llii' waii'is i|i'ii\i'<| I'mm llic iiicll iiij; ii'i' pri'Vi'iils llii' I'liiii'i'iiiiaii I' llii' u'lilij |iariit'li's. .lust Ih'Iiiw I III' ma vim II Ml I'Xlciisinii ol' l li.' liiiiiiuiaix ;,'lai'ii'i' llii'L;ia\ ^lsal■l• lllill ami llll' ;ri llll is \ i'i-\ I'liaisi' ami |iii'si'iil milv in iiiiii|iaial i\ I'lv small aim III Ills. SI I t liat il y ii'Ms, as a nili', sliirlii iiinlil. I''ai'i lii'i' iluwn llii' cri'ck tli<> L'lilil 1 oiiii's liiii'i', Inil alsu iihhi' almnilaiil, ami tin- rii-tii'st. 11- LTI'aM'ls Mills lai' illsi'ii\ I'li'il. wliirh Is nil Mill rl' s clailll. pail lit' I aliiivc I't'li'i'iril 111, is sii iialril a iiiili' nr sn lii'Inu ilii'liiiiii 111' pay ilirl ami ntlilains p'1'1 ill ^'I'itiiis 111' mi'iliuni si/i Slill raillni- ilnwii llic • •reck till- ;riil;iii;; II' I'irlli's I niiLri.'1'l laki'ii I'nim ill valiii' I" rum •i'"i In "i'l an' I'niniiinii. 'I' tlii'rri'i'k was rniiml alini:l hall' a iiiih- lu'lnu ilii'limil nl' pa> ilirl ami wi'ii;lii'i| ."i niiini'S. Il I'liiilaiiii'il a small pnipnil inn iiri|iiarlz. Il is iiili'i'csl iiiij; In mill' llial, hi'siili's I hi' ;;iilil rniiml in I hi' In 'i I i if I ho main sti-oani, a iiiinilM'rnr llii' small raviiii's nr pups a Is nilaiii ^rnhl. 'I'llis ;j:nlil is I'liaisi', nwinir In lln- sli'i'p slnpi- nil wlliill il lii's, lull ('iiiiii;;li has liri'ii rmiml in I'lii'niirayi' niininir, sniin'iiiin's with lair ri'siills. /■(/')/(/.- ■riiiiiiiirhiiiH ihi' sriiisis whii'h rniisiiinii' iIu'Ih'iI ni: li\ lilr. I.ailii' lilnrks nl' this r>iiiiri( lit 1/ I'di'k an' many \ I'iiis nj' ipiaii/ rairyi ipiait/. air i-iiiiiiiiiin in lln' .u:ia\ils. ami nirasiniial piii-i's slmw rrcc ihl. Tlic laij:i' piins nC nisiy i|iiaii/. mi iiiishii nu' aijil panning, iiricli yichl iiiaiiv liiii' " i-oliiis" nl' ;;iilil. whih' llii> pyrilf wliirli is si'paiali'il I'lnni llii'si' xi'ins ami alsn rinin ihi' srliisls (in wliirli it iii'ciiis s| pnradii'all.N ilissi'iiiinali'il I yifhl nlil alli'i' mast iiii. I'll 111 was also I'niiml In a i|iiarl/, M'iii in plai'r. sitiiali'il in nlli' 111 I III- ia\ iiit's ii|' piijis iii'iir llif lii'ail nl' ilir i-ni'k. Tlnsi' Iliiii;rs slmw that ;iii|il iM cid-s i|ls.s/;|/|jf|i|l<'i| lliniUfiliniii ihi'sihi-i .'iinl Ihl' ipiart/. vi'iiis, ami is appiirciitiy assdclidMl willi pyiih' ami nihi'r snlphiili's: ami h||ii'(1 Illf ^'l■(l\l■l riiiisisis cntiri'ly ul' (jiliilns iiniiu'iliaii'ly ih'iivi'il lliilll llll'Hl' Kirlis, Urn MiMII'ff III' Hie placiT iinU\ is ipiiti- rcilaiii. 'I'lit' ^llll'lllli «lll»'ll fs liiill'il III CraiiiiH'iils 111' all si/i's in tin- v'nivi'ls. is alsn (|('l'|Vlil| I'hMII (||'(|IInI|h In llll' si'hisl. Smh a ih'pnsil nri'lirs alinllt IP .■{•J4 (ll.(»l«J(iY i>|- llli; VI KON (lul.l) DISTKICT, ALASKA. I.IKKI iVcl mIiiiM' till' ll|l|M'lll|il>l rl.-lilll llfillL' WOI'UimI III I^IM,; lli'l'l'tlll' [.'.•ilcii.i cicc'iiis ill iircL:iiliir lildtilics ill i|iiiirlz M'iiis. (Mlicr ilcpnsilM an- rmiiiil in I lie \ ii'iMit \ . I.I. \rn II t 1(1 Ik Till' liisi u^'ilil ilisi'iiN iii'il (111 ( ilacii r ( ii'i'k sitiiis IoIuim' I ii in Is'.iJ. Ill lli.il ycjir, lidwi'V IT. lull lillli- work «a?. Tin' iiisiiny dl' I lie y:iilcli >lin\\s im riTunl of •• liiHiiii>," liiii till' ,\ icid li.i- 1 n Tail' Iri mi I lie si art. In .liilv . I >'.'<;. Ilicii' \M'ic saiil 1(1 lir al I ]'•<' iiii'ii al wmk. 'I'liis was Itiil IIuit rmiillis 111' till' niinilii'i' i'n;^aL.'''l lini'iii;; llir nimi' Inisv part i.l' llic spring si'a.siin, wlicn tin- .siippl.\ nl' wati-r wasanipli' fur sliiiciiiir. Shi 1 1 II of' mill I/. Till' valli',\ <>( ( ilacii t Cii'ck is Vsli.ipiMl. nulalilx in llii' iipjiiT pail, willi siiii's iniiiiiallv stri'p. i'S| ialiyun llii' mhi'Ii. Ill lilt' III WIT part it is less t ii'iiclianl. clialiiiin;,' in ruini riinii a V ^'lad- iially to a U as il upciis mil tnwanl (iuld (i-iM'k. 'rilc l^rlllliT sldpc nil llli' IKillll sidi', as rdlllpaii'il Willi llial nil llli' sinitll, SI'IMIIS 111 111' ijlli' 111 llir niiirr liirrrl t'Xposliri' In tllf ra \ s nl' llli' Sim ilui'iiiu llu> lull;; daxs of suiisliiiii' in tlir siiiiiini'i' imuillis: sn llial I Ills siili' is siiliii'i'li'd 111 a ;rri'iilt'i' lii';.'!!'!' Ill' iliawinir and n-yfclalinn. and ('iiiisi'i|iii'nliy wi'al liiTiii;f and crnsiuii lakr plan' iimn' i-apidl.\' lliali nil llli' sniilli sidi', wIkti' iIh' rni-ks ri'iiiain Inr tin' innst pari snlidly t'in/.i'ii I lirnlly:llnlll llir ;;:ii'al<'|- part nl' I lir slIliillKT. It is alsn pnssilili' I hat a lilt nr iiplil't nl' tlii' i'i';:inn nii tin' iini't li may liavr npiT- tlli'd til sliit'l llii'si' stri'ams siiiil iiwai'd. and I liilsi'aiisi' t lii'iii til inl irncli liii'insch I'S ill till' snlllll sidi' nl' t lirir \ .'illrys. II is also al nni'c nolici'alili' lliat I lie sniilli side nf til.n'icr Cri'i'k N'ailry is ninr inspiciiniisly t'lii'nmi'd liy sidi' irnlclii's, ni-. in miiiiTs' laii,;;iiai;i'. "" pups," I liaii istlir imrllisidi'. Tlii'si' pups, alimil a liail" dn/.i'ii in iiiimliiT. vary t'nim iialf a mile In _ nr ninri' inili's in Icimili, and ari' nl'ti'ii sliai|il,\ t ri'iii'liaiil nr V-siia|»'ii. slmw inu' a ;;ri'at ('iinci'ii- t ral inn nl' (in« ni'iitt iiii: li,\ tin' iitt If st rram wliidi drains tlii'iii. 'i'lii-ir ;;radi('iil is. nf cniirsi'. mncii stcrpci ilian I lial nf I lie \ alley ny main y;iilrli, linl,iiki' tlii' main \ alley, eaeli imp nsiially In-ads in a rnn;rlily amphillii-at rical fnrni nf its own. Nnrnially, t lir pups an iipicd iiy \ cry small si reams; in sprinu't imc. Iin\\c\ cr, w licii melt in;: is rapid, the claims at their mm it lis a re said m he iiincli harder In wnrk, liy reason of the siipcraliiindancc of waii'i' which tlicy iliscliar;j;i'. 'I'lic head of (i lacier (reck \' alley is (|ii it e steep and is of I he amplii- lliealei or cir(|lle type. The fnriii seems In lie due In Ineal ;^laeiers nr masses nf slid w and ice w hieli aceiiiimlale in the heads of the ;;iilclies during- the Imiu cold winters and usually melt dniiiiu' summer. Where the condilimis of precipilation and allilmle of the head of the ;f|ileli ill relation to the sun's rays arc favorable, the aeciimiilal inns ma\ 111 me perennial, as seems to he the case al the head of Sipiaw (iiileh. near w here the l)a\i;- (reek and the Miller (reck I rails m 'pa rale. l''roin the more than ordinarih' liiu:li di\idi' here, the head of the ill 'iii »ll 1111 1 ill'l.i II l>Iii(.!N(. til.A< II l( ( i;i IK. •A-2: lllc'll lIc'si'clllU \iT\ Mlinl|(ll\ 111 IIji' MnrlllHi.^I, ^11 111 liilllMltll'il il- l.lll' iii'rilii; iliiriML' iIh' ii'cii mill iiiiH'i' 111' II" mil iiiiiiii;.' Ill iiii UN llll' Mlillilll' 111' .llll> I l-^'"'') : ll«.ii|il,lll|i> i|i'|liiMt ill' ^liiUN ;|||i| M|l|ial'l'Ml l,\ IIHil'l' lIlMII Vtllllllj III' li'IrliiM'ii hv I I'l'iiiaiiiiliT 111' I III' oiiiiiiiii'i'. I ilacii'l' (li I'U i|i'i'i\i'> il> luiirii I iiiiii llii'-i'ji I riiii>ii'iil !.'l.■||•il'l•^. Nsliii'li 1111111 i'M'i\ wiiilii-, aiiil. (|ii\Mi mil il lali' ill I III' « iiilci- 111' »|ii'iiiL;. iiiali'riall\ iiiiiil'i-ii' in •..uin' Inralil ii'> ^^ il II llll' lllilirl-s' NMH'k. Ill I III' ll|i|ii'l' pall 111' I III' L'llli'll li'lli- iiaiil> iirMiiiic 111' I lii'M' ^lai'ii'i'Mliiiilil li'ss liii;;i'r Iliiiiiitjiiiiiii till' MiiiiiiH'i III' 1 1 Mil' pi'i'i'iiiiiah I'lir I'liiisiiji'ialilv Ih'Ihu i lir ii |i|ii'i' I i unto ni' u Ih'I'i' |iiiispi'i'l in;; lias liri'ii cairirij mi, a-- lali' a^ I Ih' iiiiiMli' nl' .liil\ i In' rn'i'k liaiik-- al rn'i|iirlit iiilrrx als I'm' -.1 iililii's ni' Im' •»■ iiiuit' \ ai Irmii iii'ai' I In' iiiuiil li nl' lln'i'ii'i'k In \\ illiiii a mile nr sii III' iis lirail llll' \alli'\ has liccii siaknl niT. making' smni' sixt.v claiiiis ill all. .\ I'laiiii mi (ilai'iiT Creek is ."iiin ii'i-i in |i'iii;i||. liH'ilsilii'il paialli'l Willi iIh' \ all('\ . ami i-xli'inU laii'iall\ I'lniii rim rock ti> rim imk. nr as I'ar in 1 liis iliri'climi as i lie _-ia\ il ili'pii*it> ma.\ iiiTiir. In llll' iipjicr m V-sliapi'isi'ii\er\ elaiin. it allainsa wiilllinl' rrmii J-"i in I r mnre yariK. 'I'lie ihiekiiev^ nl' I lie LTiaVels is mil\ S feel nr less ill llie upper pari 111 Ihe \aile\, Iim; inereasi's ;rrailiiall.\ 'III" iisi ream, until a I liieUiie-s nl' I'n nr iiiiii'<. Cci'i is leaelleil. /;,'. ami lari;i' leii! ieular ami irri".;iilar masM'>. Near I lie lieail nl' I lie u'nleli. mi i lie upper sinpe 111' llie ili\ iile lielweeli < ilai'ier ami Miller I'leek-., '-i i a liilinla III is llie ijUailz llial ill plaees il I'mnis almnsi lliewlmle i k. Miieli nl it. Iinweser. is in llie rnriii nl' lesiiliial linw I'lers. wliieli lia\ e prnhaiiiy resiilleil rrmii Imii;' peiimls nl' weal lieriiii; wlliell I'nl'llierh inelnseil llieiil. .11 nl' !l uiiil rv nil Tile milv plaee in llie^nilell u lie re Ll'iililliearillir i| iiii: iiiiarl/ lia-- lieeii i\[ II. .1. lieln « |>l>en\el'\ liiwar.l tin- Inuer rl/ \ eill I>^ inelies in I llieklless iselaimeil eovcreil in plaee is on elaiiii N part III' llie ;;illeli. Ill re a liv I lie iiu iii'is In assa > s.-, ||, ■ Inn. ■riiwanl tile heail i. i lie •.•nleli. where Ihe rnek iiiiteniiis near the ereek, the strike nl' ill.' -^i hisliisit.v is N. 'M K. ami the ilip -.'."i SK.. bill larllier ilnw 11 Ihe ilip seems 111 1" mii'lliwanl. In Ihe Inwer pari III' tlie^'llleh the slrike if si'hi--ln,vil \ N. I I W . anil Iheilip is 1.' N. ( )|l the I'iil;,'!' linl'lli nl' (ilaeii (tip S SK r ( ri-'k the strike i- N. IJ K. an Urm'i.l.t. — The I'ra.^iiieiils in the ■;i'a\els are niaile up enti,el\ nl' IMAGE EVALUATION TEST TARGET (MT-3) // 1.0 ■^ I^ 12.2 ! -^ IIIIIM lyub 1.8 I.I L25 iU lil.6 — 6" Photographic Sciences Corporation 33 WEST MAIK STREET WEBSTER, N.Y. 14SS0 (716)872-4503 1 '1' • ;■ m i »' ;i2(( (;i:oi,(i(iv ov tiik yikon goi.d district, ai.aska. scliisis jiml (|iiiicl/, ilcrivcd I'l'diii tlic adjacent licil-rcick. In tlif iijijicr pari (if tlic u'lilfli llioy aro more aii,i;iilar tliaii in llic lower jiarl, and Ilic di'posil SDiriftiiiK's rcscmlilcs laliis; rarllicr di)\\ii tlic valley sand and clay appear and furiii a conspiiiidiis jiart of lln' deposits toward the nioiitii. 'I'lie I'ollowini;- vertical section, rou^tily eslinialecj on <'laiiii -'ti, above the Discovery claim, is a fair averaije of tlie jrravels for Die middle and njiper part of the ])resent di,u^i,dn.us: Sirtiiiii ( fniiii Iti/i iliiiniiri(ril) im rliiiiii .'", idiarc tlic l)isc(>r('ri/ chiiiii. 1. Alhiviiil soil anil moss. Neiiictiiiics nincky IJ V,'. Pflibles iif (]iiiirt/.sc'lnsf as lari,'(! iis the liancl, with bowl- ders iif iinartz often venient while yet near the surfaei>. '^onie of the(|iiart/. bowlders in these ujjper trravels are traversed l)y small veins of pdeiia; also upon and in a fi'a^'nient of scliist was found dissenunateil niala(dnte. In the lower layers or " |)ay irravels"' (No. t) are found frau'menls of botryoidal iron ore. In the .tridd from these uravcls occur nufiiicis up to several ounces in weijrht, often with crystalliMe (puirtz still adhering', showinj;- (dearly tlio oi-if^inal associa- tion of the two. F'liKKii I ur,i;K. I'oKci' (reek or (inhdi ris(»s in the liald Hills. whi(di form the divide betv\e(>n l'"ortyinile and Sixtymile cre(d( the Canadian mounted jiolice. at Fort t'udahy, the one hun- dred and forty-tirst meridian, which constifufos Hie iiiferiiaf ional boundary line, crosses f'okei' <'reek 1 mile below the divi(l(>, yi-t tlicii' lias lii-cii im ciMiiM'ial ion Ici (IctcniiiiM' oihcr iminis un iIh- lim-. A irri^al iiiuiiIm'i- ni' t lie iniiicrs arc iinrrasniiahlx iiu-iim-il i.i ili>|nilf l ln' ai'>iii;n\ nl' i lie siii\ |.\ , mihI many tliiiik even lliat MilliT ami (ilacii'i' c-ii'i'k- air in Alaska. Iml, so far as we an- alilf to jiiiliTf, iIhtc i-~ im ii'a-.iin Im- tlii- liflii'l' IldwcviT. till' l.H-atiiiii lit" tin- lniumlai\ has iin iiM|Hii lami' i>\> I'nkiT Cr'Cfk, I'm- all lln' paying i-laiins an- wi'll uiiliin ilic' Alaska liiiiils. Last spiiiii: ( 1 s'.ic, 1 ihi' tiiM wmk was ilmii' mi Ilii' i^iilcli. anil in lli' iiiidilli' of .liilyuiily tini-i- i-iainis \vilt a"> the <-ri-i-k lia miles Itelow lliis llie fall is iriadual, heinir sea reely over I.lo feot to the point where I'oker Cieek enters Walker I'"ork. 'i'lie valley is rallier wide, willi side slopes axerairiii;^ :.'o near the liouiidary. and Iteeoniin;: less sleep farther down. .\t the inonl h. tiy the eomliiiied erosion of the I )a\ is. I'likef. and Walker l''ork. holt Dili lands half a mile wide ha\e lieeii formed and I he lid^rcs have been ledlleid to si itll.rollinir outlines. These uellt ly ell rved riilires are termed "" houdiaeks." The cause of the sleep irradi' ami aiii|iliitlieat lieal form a I the head- waters is. as upon tilaeier (reek, ilue to the fael thai for a part of the year the valley is oeellpied liy Slli.ll Ldaeiers. .\l the time of visit, ill .Inly, areas of siiow and iee from a hiimlred square yar'ls to an acre in extent still existed at the heads of nianv of the smaller hraiiehes. "I'o a limited i-xleiit. therefoic. the snow is |ieiennial. for alioiil the laller |iari of .\u.i:ust or the lirst of Septeinlier the lirst, snowfall oeeiirs. Sunn- nieltiiiir .i:oes on iiiili! I he last ol Septeinlier, hill after that time tin- aeeumiilatioii exeeeds the inelliii!.' until the month of .May. I'reeipiiai ion is not trieai in i hi-- part ol' i he eon n try, seldom over I feet of snow reinainini: on the level lliroiiLihoiil the vvinler. The eiiiiditioiis are favorahle to the foitiialion of an iee lield. or m-vt'. durini: the eii:ht inonihs of vv inti'r. There is almost, no motion, however, iiiiid the meltiii;: in the middle ol May. then toIll,Mles of iei- are sent down the slopes, the iee eats haek al tile head, the silp<'i}xlacial. and in a less de-rree the siihirlaeial. stieanis lend to widen the valley, and the eiriple form is inteiisilied. 'The irrealest ' elTei't of this Ldaeial aetiiin i> shown ai tin- head of the valley, for that, is the reiri'ill where the iee reliiaills the lollLtest. livlhe middle of ;')-JH (iKoLO'.Y OK THE YUKON GOLD DISTRICT. ALASKA. •luiif llii' Miow lias i)i;i<;ti«!iilly all di.sapitt'Jirfd ft- lie lower valk'V, Icnviiii,' Diily small i)at<-li<'s on the liciu'lits ami a1 llic heads o aviiios. On til e SKles I) is MTV act i\ e ill \ve(v fi r ti IIS cirqUi lusideraltle talus aeeiiiimlates. Frost Itreakiiij; ilowii the elilTs, since there is scarcely a (liiiiiij; the whole ye.ir when the teIlll)el•atnI•(^ docs not fall lieiow t a* least once: the diurii.il raiifre of leniperaturo is ;ilso •ceziliL; polll very irrcat, son ■ limes as mm ther< h as 'iH de^'recs in summer. AVherever the slif^htest holil l<>r ve^'etatioli a thick carpet of moss coV(M's evervlhiny: and serves to protect t lie surface airainst the me- chanical action of rain water. There i-. howi-ver, a How of the vejie- t at ion down tin- slopes, the effects of which are observed upon many of the steeper liloss- overed hillsides all alonj: the l-'ort vmile-Sixt viiiil divi ail' especial Iv noticealile at tin- heails of (iold, (ilacie and Poker creeks. The appi-araiice presented at a distance is that of escalops. These are foriiieil liy little rid^'cs of moss which lie on tliti slope, convex <'iid downward, resemhlinu' in miniature the terniiiial moraines of a ^rlacier. The riilires are din- to a slipjiinfr of the thick moss a id decayed xcuclalile material upon the fi-ozen subsoil or roi'k. The movement, like that of the j^lacii-rs. takes ](lacc only i)art of Wio year. In the winter, when both the moss and tin- untlerlyinsj; soil arc frozen solid, there can be little or no motion, but with the first nielt- iiifl a dowiiwaril slijipiriir beirins. As the meltinu i)roy;resscs more and more o f th iiiick'" iiioM's: but there is .-i limit, fjenerall.v not more than IS inches below the surface, where the ground is frozen tl le vear imi lid and there is no motion. Sometimes there is a sm escalops, the rounded iioinis of whii'li travel faster than dell acceieratioii. ami a slight landslide is the result. Obviously, owiiiir lo the diirereiiees in aiiirh' of diffi-ri'lit parts of the same slope, the dowii-creepinji; will be differential, and the resiilfi is seen in the waves or the sides. lit il-riifl:. — (Ji'iierally after the fii-st sleep descent the valley is covered with moss. Here ami tlicre. where the stream has umlereiit a bank, where a landslide has occurred, or in the bed of the creek itself, outcrops are found. The i-ock is the saiiii' for f ho whole length of the valley — a bluish-black qiiartz-sdiist. often grai)hifi<', coiitain- iiig many (|iiartz \-eiiis which are usually parallel with the schistosity. From the divide to witliin IJ liles of the mouth these ro(dvS dip '.ikI strike a little north of gently to the south, generally not over east, ])arallel, for the most part, with the direction of the valle.v. .Tu.st above its jiinclion with Walker Fork a low aiiticlim les in, strik- ing N. W° K., and th a revei-se dip of lo" to 1.") to the northwest. (imrrJu. — .VliiiosI all of the gohl is extracted from the bottom ])oi'- tion of the gravel resting on the bed-rock. Tli IS pay dirt. ihicli coiii])o.sed of subangular, waterworn pebbles of ipiartz end schist, ^■aries greatlvin fhickncss and width th ith it is ;i feet thick, and from liere toward the hea!) pay din (■(lines ,i layer of barren ^.navel 1 lo i. feel tliick. This is •generally eoniiiosecl (if idnnded or llaliened fiaLrmcnis of vein (|iiarl/ ami (inart/.ilie seliisi . coarser than tile pay irra\ ds and showiii;: h'ss till' elTeels of assort inent liy «alel'. Tiiere is a iKipiilar impression aiiionu- tiie miners that the very often tliiek •rravels in this and other Lrnlches are composed of maleriaK transported irreat dislain'es, and that the aireiit of transportation was a irlaeier, rather vairnely tlidiiirht by them to lia\e o\crriin llie whole eoiliilry. There is nothiiiir, howcxcr, to justify the idea of a continental lihieier. or even a valley udacier of Lrreater per- niaileliee than the t ransicnt ones before (|eseribe(i. The pebbles and lM)\vl(lers coinposin;;- the i;favels ha\ c a dist iiietly local origin fi'oiii the iiiiiiKMliate draiiiau'"' basin of I'okcr Creek. In part the (leposits are stratilie(l, and when thoy are not so there is e\cry other reason to Ixdieve that they were laid down in the \ alley of a stream. .V certain arraiiLTcnieiit observe(| in the iipp(M irravcl at .Mc( 'larty"s claim, thr quart ers of a mile from the month, showed that 1 he deposit, now s or in feel abiiv'e the stream bed, was formeil in rnnnini: water. .\\ this point bowlders of stretched (|uart/ite and vein (piariz. some of them afoot in the loiitrest diameter and -'i to ti inches thick, are aiiaiiy^e(l with their longest a.xes |iarallel and incline(l downst ream, jnst as in tlie present stroain bed. The aii;:le ot' inclination is about l."i from the vertical, sliowinjj: that deposition was made in swiftly riinnintr water. Xot iiuieh ditVereiiee was noted between the upper and lower gravels. If any, there was iiuire saiul in the paydirt than in the bar- ren jrravel. showinjr, perhaps, a slower current dnriiiir the lirsl deposi- tion; lint, as a whole, the deposits are coarse throiii:ii(iiit and \f\\ similar to those now beiiii,' laid down in the bars of tl reek. 'I'lie gravels have been cut into by the present stream, snir.irest injr that the relation of Poker (feck to its base-level has changed. Kither there has been an elevat ion at its head or the level of the main draina;:e of tin? count I'y has chanued. In either case the creek has acipiired ncu aetivily and is eorrading the older (leposits. In this revival the old stream valley does not always correspond with the new, for while in llie lower part the pay streak has been found near tln> north side of the creek, pros|)eels fai't her 11 p have shown it on the op|iosite side. However, owiiiii to tin mparalive nai'rowness of the \alley, the liK-atingof the pay streak is nearlv always easy. OiriiiT' lilt of i/olil. — (iold occurs ill greatest (piai titles within 2 miles of the month of the creek. On the iipjier part of the creek it is absent, or is found in very small (|Uanlit ies. It is bright w-llw. in subangular to angular grains, which are seldom over ii.(>s ouik . in weight. The shape of the grains is suggestive of a near origin. No free gold ill (piart/ Veins is known on I'oker (reek, allhongli a few small niigu'els, in which the gold has adhering to it pieces tif quart/, which have not lieeii worn otV durinir transportation, have been found. h 1 ayO (;);oL<)(;V of TIIK YUKON OOI.D T)I! * HKKK - i.V On Davis ('reck claiins ai'i' si; Tccl ill Icii^rtli, ami aro oocii- IiIimI ii|i Id williin a iiiili' and a liaif of tin' e\eral small laxiiics come in from the iiort li. TJ ■reck llows throuirh a narrow \alley toward the west. Tl fTcntler. iree mile: conies le: I rolll lis source 1 I licmis to llie southwest, Ih ■■Iccp. till' \alley liroadi 111 >l. if 111 Md< The valle\s of I'oker and Davis creeks are markedlv dill'creiil. In the i'oriiier the steej) u'raanion iile\', and ordlnai'\' water corrasioii lias liceii more impor- tant ill the dcirradal ion. Ill il-rmk. — I'ortlie rn>i :; miles Davis (reck Hows iiaralhdand near to the axis geiith of an anticline and on the soiitliern lliiil Thedi Host ne\er o\<'r In . to the south, ami the striki p IS very east and west. T'orlhi' last J miles the st ream crosses t he st met lire, ]{i'versed dl])s are met, and an unsyiiiinetrlcal syncllne, stee[)er on the north than on Ih ■eolith, IS crossei 1. Til followed to the .south bv tl Poker (ri'ck anti<'line, noted abo\e. On the whole, h owever. those re minor plications in the soutln-rn limb of a ^reat anticline st riki a east and west. T le Kei l-idcks here are the sami- as upon I'oker Creidv and Ihe Si.xtv- niile divide — schists derived from i|iiarl/.ltes, in which ((narlz xcinsof vary inj; width niid cxlcnt occur parallel to the schi.stosity. Secondary mica is fre(|iiently developed, sometimes iriviii;; the ai(pearaiie(> of ijrneons rocks, but upon close examination the metaiiiori)hic charaetcr is seen. Often there are ^rraphllic layers correspond I nj; to orlfjflnal hese irraphitic schists were parllenlarly noted on the ■sluiiy portions. 1 he: Discoverv claim, one-half mlh> above the month of Ihe creek. Sl'ini:.) (in,< 11 DHii.INdS: nvNIS CIJI.KK. 3.11 (.■/■(inlN. — 'I'lif ,i:i-a\-.-l lias llif sain.' dia laiMiTisI ii'> a> that mT {'..U.t (reck: ils tliii Uiics>. hcAvcvcr, i- UMiall\ imiI s,, -n-al. \i'ar 1 he inoutli lln' >ci-li(in is as I'dlldus: Stfllnii II, til- till iiiiiiilli ff IhiriiJ Cm I.: Muck (ve<;ctal)li' iiMitor kihI m'iI • C'oarsi- i,'ravi>l i bowlders oftfii s im-li.s in iliaiiu'Ii'i- 1 KiniT -i-iiv.'l, pfil.M.x, au'l litt!r sMiid; .-...ir-iT ai l.ott..in I'icil-rock, Mark siliii'Dus srliist. i; t I Till' lowci- I Ccrl isllic •■ ]ia\ iliiM," and il \arics Im.iIi in lliirkin'ss ami wiillli. Al 111!' |)isr(i\ci'\ claim the lliicUiicss is I iVcl ami ihc width is sair s inches, and in this laxer dl' rutti'ii im-k ciiai'se. well-woiii .i;nld has urtcii 1 n lonnd. The dcci,in|Misil inn iiiusi ha\e iMMne alionl snliscipn'iit tn the dcpnsil inn cil' the ;ri-a\eis, for a stream si i c'd rock. Sdiii-ri III' (/nhl. — The L'lild I'lnind ml l)a\ is (reek is coafse; the Ui'ains are sonietiim's r()nmlenart/. veins occur here. as Creek. e\ crywln're in tlw schist. On l.owry's claim. 1 mile fi'om the month, oi f these vi^ins exandncil lies liorizonlal and is In (H' U' incln's thi(d<. So far as opened np il eMcmls latcr.-dly. parallel to the schistosiiy. I'oi' i'.". feet. Macros,-,, pically the quart/, is cross(>,l liy , 'racks, whi,-li ar<' often occupicl \ iciiiailv!il)l\- "lilVcrciil fniiii tlifil (iii llic iiorlli side of llic ridv'i'. Jiiiil imlci'il I'roiii most nC llio Kortyiiiilo district. Tlit' coiiuliy to the soiiili is iinmd and p'liliy slopiiii,', and is slifflilly and cvt'idy iiKli'iilfii \t\ stri'Miiis wiiicli rise in a low rid^'o with I'onspiciioiis cluiiips of liills line and lliiTf. Tlicsr liills jirohaliiy form tlic divide hclwccn till' Tana na and llic N'uUon walcrs. and arc lcculiar to|)oi,'rapliy .just described, foi-. as shown on the map, its various brandies drain a com- paratively « idc bell, they ha\e cut coinparat ividy slijfhl \ alleys. Jliil-rinhs.- A\ the head of Chicken Crcidc oiilcro|)s the larjjc srraii- te dike which forms I hi' crest of the rid.i;e between Chicken Creek ind I''iaiiklin (Jiilcli, while the ridjfe which lies to the east of the creek ind forms (lie di\ ide bi-tween it ami l''ortyinile Creek is composed of rrccn slates and tiilVs. which are cut b\- dikes of various kinds. In the liottoiii of the el( lasiu several outci'oi)s 'iiid prospci't lioles si low jivtiy or lilack shale, and sometimes impure coal. 'IMiis rock is evi- dently the .same as that foiiinl on Xapolcoii Cr-ek. At otlior places olivine-basalt forms Hie surface, and (his ro(d< is said to outcrop at in(er\als over (he whole creek basin, and on .^'ycrs Fork to form (he walls of a canyon Pm feet in depth. (Irtirils. — In the travels the mosi iiromineiU rocks an; };rccn tuffs and stales, liesidcs basalt, shale, and some coal; thert.' is iiiueh chal- cedony, and \ eins of cinart/. showiiii;' comb si met lire; also some trran- d (luarl/.ite-schisl, and ])leii(ifiil fragmciUs of irbh Chicken Crock has liitherto prodiiceil very little, (he di'Velo]iiiien( hcini; s(ill in tlio prospecdnu' statre. The orij;inal discoverer, liob .Alalhesoii, has prospected here for several years. Inil in general the difijrii'.ys atlraeie cli^iuiii '.i."i miles liy livcr I'lniii llic Vuknu, ami llo"-. iiiln tlic Sdiilh {■'(Ilk lit' l''orl.\ mill' ('rfck In iiiilcs jilmxr I In- Noi!h Fork. It is >^ mill's lonu'. iniil Hows in a itcin-ral f.ist«'rl> iJiiiTi ioii. /;, ,/-,or/,-,s. 'i'lir locks lliri)iiy:li \\lii<'li lli.' ^miIcU is nil aiv .•liidly liiifji- ami li.iiiihlcml.'-sciiists. willi iiili'rhiMl.l.Ml maihli'; llicse arc ciil liy occasiciiial dikes. ' Xiihin nf really behind rock -ales, ihrou-h uliieh ihc-civek lireaks with an increase of ijradi'. In cross-section the valley is unsymmel rical. the steeper sid.' Iieinj: on the south anf burniuL;-. Oiu'dialf mile above F.-hlis s .daini. on the riitlil-hand si.h- of the rwvk. the pay streak was reaehe.l under 1-' feet of "ravel and a prospect of loc'ids toihe pan oblam.Ml. Mill farther abov... on theopposite side, asmall prospect was alsool.tame.l, and •! miles from the mouth a cabin was built in the early days, but it has not be,-n oecnpie.l for !h.- last ih.ve .vars. nor has th." ^rround in that vicinity lH...n worked. So active min.n- ..perath.ns stop at I miles from the mouth. Th." "ravel is uen.'rallv from s to |n feet thi.dc on the lowr c'reek, an.l is" comi.os'ed thron-hont of -rranite, marbl,-, .,uart/.it... vein (ii:()i.oiiv ov Tin; vikon (ioi.d distiuct, Alaska. c|ii.iil/, aii'l Miicii-scliisi, I lie ri-iiu'iMciib iiviiiiT ill si/i' from liowiilcrs 1 Iniil ill liicir liiimc^l (liiiiiicliT Id sin.ill pchlilcs ainl smihI. 'I'licso riaLrnii'iils ail' siiliaii;;iiiar In aii;;'iilar, \t'iy Ni'ldnin sliowiiii; cllVcIs of ■rri'al lians|iiirlalioii, ami all' ill-a^sorlcd in rc),Mr(l losi/c 'I'licrc is no cN i'li'iicc of si ral ideal ion cxci'iil in llic iip|)<'i- valley, wjicre in sonic slieaiii-cMits tlicri' is a sliulili inilicalioii of lianijin;; of linci' and coai'scr iiialciial. Almost all of tlie rocks coniposiiii;' I lie ^'ia\ cl arc dci'ivcd from llio drainaL'c area of ilic creek. Tlic .i,nanilc is from a at dike which crosses llie cvlrcnie liead of llie xallcy and runs aloiij,- bclweell Franklin y the co\ criiij,^ of moss, but its oiitcrojis lia\e not, heou fdiiiid. ()i! Cliickeii Creek, just across the niouiitaiii from Kraiikliii (Jiileh, till' same rock has liccii found in place. The rock is compo.sed ■iiainly of minerals of lii;;li s|ic('ilic ura\ity (olivine .')..'!.'!, a uj^ite ■'! -f, hoi'iildcndc I'.'.i), and is of much iri'cater spceilic ^rravily (over •'!) than any of the quart /.-schists or iiiarhles '• liicli make up the rest of tlic this account it is more closely associated with the },^)ld. •avel : The pay streak is ifcncrally thin, sc ireci\' ever over feel, thick, and in maii\ cases the uravel itself is entirely barren. In many of I'd-roek the claims tin' lid is taken out from irrci^ulurities in tl surface, very little beinu: derixed from the irravel. Such is the case on I'c^ar.son's claim. I mile above the mouth, where the ovcrlyint; bar- ren f^ravcl is III feet thick. .Much coarse pild has also been taken out. ill the bed of the stream, lia\in{; been washed out of the eravels and deposited under a natural rillle. On Feddis"s 111 there is in the bed of llie creek a which \aries in a short dislance fi quartz vein iiiclii ■J feet in tliickne^ This vein is in mica-.schist and is parallel to the schistosity, strikiiij; acre iss the creek and diiipiiiu; u]isti .Aluch coarse ijold has be(>n taken out of the ril11(> just below this \'ein, and .some crvslallized ■iilver. The miner was if^noraiit of the value of 11 often thrown away pieces found in his s lui( alter, and had hich but one specimen which had iircscrved was not at all worn ami had evidentlv not beei lie carried tar. ilso been lo .V few inches abo\'e tin quart/, vein mentioned {{old lias und in les.ser quantities Th lose connection of I he ^old and native silver with 1he(|iiart/ M-iii siiirjrcsts that the vein itself has yiehled these metals, althouirh no free yold was seen in the present oulcroppiii};. The ;;old is coarse and ani,'ulai', and often has iiartielos of (juartz adherinjr tti it, showinj; its orij^in. Small nufiucts are common, and (in. Ill nii.i.iM.s: nai'OI.i ^N <■|;^•.^K. :;3: 11ici-c i^ xiTvlilllc li I- lliiiir L'liiil. I'l'iiii l-'fiiiiU,liri «;ul<-li h!iv«« hcc'ii liilsi' ii ilic \\\i> liiiirc-.! iMi,i;;r('ls iliscii\iTi'ii •li->- tricl. 'I'lii' lioi \\.i> IihiihI Ii\ t'iiin-;iil l»alil. in !■<''*. :.') iiiili-* alMivt- tlic iiHPinli ill llii' mavi'l. Il «;is lliil-ii\a! sli;i|"->l. it^ l..ii;:i>M tliaiiK-I^T ■11 liiclu's, iiMil IriHii scvi'ii-i'i^litli> iiii'li 111 I iinli tliiik. Il» \\.-ii:li> «a> lid Diiiii'i's. .Hill il WHS Willi 11 .iliiiiil "."iiiii u lien taki'ii out xf th>- ;rrl iiuuiii'l "a^ laki'ii mil frmii tin- iiiuiltli ..f a ■•mall tiully oil llii' SDiltli siiji' nl' llii' \alli>. Tlii- UM- woitIi *l*:!'' at the val<' I'l' i^l" l>i'i' iiiiiici'. \ \|M| 1 liN I ttlJ.K Napnlcoii Civck lliiws into tlic Sniilli I'mk of I'oitymil.- I r»-.-k on till' ritiiit side, aliipiit •"( mill's iilmvi' l^'ialikliii (iulrli ami i' iiiil«-> 1»'!<'\v Walker l^'mk. Il drains a cKiisidcialiU' ]iarl nf ili'- i'"^i'>n U-tw.-.-n Walker I'nrk on llie soiitlieast and tiie Soutli Fork of Fortyiiiile Creek nil llle West. ,S'/('//;< III' mill i/.—'Vhv links of NapDleoll (reek flow ill vharply V-,sliai)i'il or treneliaiil milrlies. hut from f li.'ir i-oiillnfiief i|.i« ii toilic luoutli llie valley is more U-slia|ii'd. Ilin- it i- a wi.liii .if only alioiit '."I yards, and is liotindeil on Imili sides hy a MiilT i.f r.ni- glonierale: fartlier up, liowever, llie valley liioadens and s«miii attains a width of I'liii or iiiori' yards. JJiil-rnrL-.—M the iiiiiiilliof the creek the l)<'d-ro.-k is.-.>ni:l"mer:ito. often coarse; lint about :!iiii yards aliove the month it ;:ii.\vs rnii-r and is iiiterliedded with occasional layers of irse sandstom- or j-'ri'- -^' about ;iSii \arils the coniilonicialc is confoi'iiiably overlain l>y Iiik- jrrit and .i.'ray sandsioiie. with thin layers of eoal-lat.- eoiitaiiiiii;: iiidis- linct plant remains. Sandstone and dark elayslate now ln-i-.iiii<- the dominant rocks, conuloiiierate oceurriiiy; only oeeasioiially in iliiii beds. A little more than Ihree-qnartPi's of a mile alxive thi- ii<..ntli th«- sedimelilaries are succeeded by a speckled iilivc-i.'r.-.-n dial>;i>«-. which is eontiiiuously exposed in the creek bed for a distanc- ..f iii..r.- than aiinar1i'rofaiiiili'.aiid,,iiid,i;iimfrom11ii'topoL'raphy, prol>al.ly.-\t.-ii.ls on up to within half a mile of the forks, where ••<«ni.'li»im.T5U<-. wit li some arenaeeiius limestone, au'ain appears. A litth- nion- than a (piarterof a mile below the forks on the north side th.- an-iia.-.i.us limestone aiiaiii appears. Il is here soniewliat nianiniri;'.-.! and apparently dolomi/.ed. |>robalily owinir to cniitaet nietani.irpliisiu. f«.r close by basalt crops out in a small elilT. Ill tlie lower iiart of the valley the sedimentarics strik.- N. -•"• K. and dip eastward at an anjile of •■.•-.. but farther up the .•r.-.-k the strike veers a liMle to the iiorlli and is almost at riirht an$:l«:-s to the trend of the valley. 'I'lic iiriuciiial set of .joint plan.->. whi.-h an' (juite promiiiem, strike X. HI W. ami dip westward at an auuK-..f >'• . aao (ii'.oLiiin ()|- rill. ^iK'iN cniA) hisriMcr. alaska. ■I ;!' A >«ciiiiiil ^I'l, wllicll scenic 111 III' llir lii'>l (|c\ i'li)|icil Ileal' llic I'dplo, trciiils at alioiit riirlil aii;,'li's to llii' liisl. Ncai- till' iiiiiiMli 111' the Nalli'.v lln' iMuiijliiiiiiMali'. a> imifil. is cuaiM', its iiniciil rra;:iiit'iits laiiiriii;^' in si/c rniiii hutc u'r'aiiis iiilmwl- ck ronlaiiis iin siMMinilary I'l' luartz in llic form nf \fins m- lenses. '\'\t: |M'l»l>lcs are riiiindcil or siiliaii;riilar, rarely flat ; tlie,\- cuiisist cliielly iir<|uarlz-|»>rplivry, a|ilili', ami utlier ijjiieous i-oeks; lilaek aiul jrn-en slale: i^reeii ami iTi :i,\' iniail/.ile, ami vein i|iiaft/. (,rnri Is. — ( iiiiill iim .< somevvlial imire 1 lian orilinary aeeiiiiiiilaiinii .jllst lieluw llie I'dlks. I lie a \ eia^e I IlieU liess lit' t lie L-'raX el. Illllck. ailll /miss I . \ erii.L; tile lieil-iiieU ill I lie llpper pari iif tlie \ illev is alimit S feet. In I lie lower pait the lliiekiiess is ahoiil I -J feel. lieiiii.Miiiieli {.'realer aliinir tile mirth side lliail or t feet of K''i'vel, which in turn rests on ciiiit'lomeralc, and farther uii 'he creek, on other sedinieii- taries and diabase. The irravcls show little assoi'tmeiit. thoiiuh the material ranu'es from coarse saiul to bowlders. The fraijments are soiiietiiiK's siibaiifiular, soiiietiines well rounded and waterworn. Of the diirerenl varieties of rock reiireseiite(l in the ,ii:ravcl, the foUowinj; were Moled: (Juarl/.ite-schists, micaceous or sonietinies hornblcmlic; vein itiiart/.: liornblciule-iiranitc; basic ij^'iieoiis rocks (pyro.xeiiite'/); ajilite: cla.v-slate. often coaly; diabase; j;rits derived chiefly from diabasii' mater'.il: and frairnieiits nf eoiitrlomcrale like the niiderlyini;; lied-iuek. Nearly all the ttold occurs uiiiler the gravels, after whose removal it is found lody;ed in irreirular lissures, cracks, and cavities in the conirlomerate. No irold in aiiyaiiiount has thus far been found on Napoleon (reek alxive the lirst two claims, beginiiing at the mouth of the creek, thoiiitli the jiravels have been well prospected up as far as the forks. These two claims areowiied and worked by Mr. Aylward, who, as early as 1>'.'.'I, foiiml irold here in [layiuj; t[Uaiitity. The two claims toirether have an e.Ment of :.',.'i:.'ti feet from the mouth upstream, and are said to have yielded thus far about *1 1,(100; >;l,u(i(l is reported to be about the aggreyale amount taken out by all other miners who have pros- .c A 48 t 1 p n 9t- 'A 1 1^; ^q m M t ; ti' 111' Li . Hi! ""•'■"" 1 Gll.CfJ DIGGIVf;-: MI-SIi.N ( liKKK. .'J.'iT poctcil (III till- 1-ii-i-k. making a total iiio.liici ion oT «]:.', nmi f,,|- ii,,' erci'k. 'I'lif ^'olil i> liri^rlit vfllmv in c.il.ir .nul j^ said i.i 1 ( lin,' quality. Ml»l">.\ ( KEKK KIMlili [. Alission (riM'k i^a iiiliiiiaiy nf tin- Yiiknii KiviTmi tlic Id't. jnio wliii'li it lliiwsat a iiuini alnnit "ih iiiilfs liclnw I-'uilyniilc t'ri'.'k ami ahuiit .s miles west of tin- iiit«Tiialioiial iMiiiiMJar.v . 'I'lic ti'cnd of till' i-r«-fk i> a littii- suiitli of fast. Inn \]u- hratii-lio llow north. Thi' ilfaiiiau''- is most r Tlii-x- ilirct- M-i-ics iia\r I ii luidcd tiij^cliiiT. ami ii|.iiii llicir iipt miii->| (•(lir<-> liii' 'l"\vcl\<'iriilc beds liave hci'ii laiil ilciwii. 'i'lic t'lilliiwini; it'|)iiil (III .Mi»iiiii «'i liv I'". ('. SciiradiT, and dial nil Aiiicricaii (.'it-ck liy .1. K. Spiirr. HKm ItllTI'iN •>*' i.ll.l HKS. \n — lii\ I IIKKK. \rar its muutli Mission (reck is a very rapid stn-ain of cloar wator alioiil - Iccl deep and Jii fffi wide. .Ind^riiiLr from ilii' trravoi bars liiiilt iiji in till' lower part of ilic \;dl<-y. it iiiu^t be a real river at liiiili ualei'. It can be ascended with a canoe or small boat some in or 1- miles. Siip|ilies have 1 n taken up by tlic miners on rafls as far as the mouth of jjouldcr Cicek. tiioiij:li tlii> «a> |iidbai)ly when (lie stream was above low- water mark. Xiiliiri (if riilli I/. — < Kvini; to tlic di]i of the rocks and tiie one-.sidcd- ness of tlie draina.ure, the cioseil valley or ;_mi1c]i type of topoi.ii'aphy is not met with till (|nite near the head of the creek. The lower jiart of the valley is o|ten to the Miiitli. tlie shtpe from the distant hills down to the eri ■ i^ beiiij;' very ireiitle. 'I'lie north side, however, presents a neai'lv 1 .intiniioiis bliitV or sti-ep slope, aloim the liase of which the creek has iiilrenclied itself. This peculiar form of valley continues in a nearly ilirect line from .Mission (reek aloiii: Twclveniile Creek as far as observations were made. /)V(/-ro<7,-.v. — The bed-rocks on .^^lssion (reek between the N'likon and Twelvemile (reek beloiiir to the .Mission (reek series, and are exposed aloiiii' till.' sleep north side of the valley. They consist essen- lially of blai'k, jjfreeii, redilish. or brownish limestone, somelimes arenaceous; black liirnilic coaly slates, and some brown i^ril. They are lai'cly faulted, but are hiirhly l"ol vciniiiu'. The coal is usually pyriliferoiis. and sometimes contains a irood deal of sulphur. It is eominon to liiid pyrite in small i|uaiitities ihriMiudiont Ihe scries, ami at times the rock contains seams of hematite or earlhy linionile. .V li-fool layci' of this iron ore was observed by .Mr. (iood- ricli in Ihe black schist and limeslom- .'! miles abo\c the mouth of the creek. The rocks of this series strike a little north of east and dip in !,a'H- eral u:entl.\' north. They are well e\|Mised a little below Twelvemile Creek; but aliout ilnii yards al. e tlie month of this creek there out- crops siliceous schistose limestone, strikinjia little iiorlh of west and dippinii' I't') N. There seems to be an iiucomformity between this series and the .Mission Creek rocks, and Jiid^^inv' from the topojirajihy, the line of contact lies in a ravine just north of the niuulh of Twelv(>"'ile Creek. ::*! (a'LCH liKJdlNGS: AMKUIi AN CUKI.K. ;i;{'.t A lilll"' iiMTf lliaii liMir ,1 mill' Miiiili 111' tlic iiiuiitlidr 'ruch I'liiilc t ri-fk. al'iiiir till- left ur wi'sl hank nt' .Mis>icin ( ri'ik. i>iciir> a I liini iiii'l iiHicli ymiiiircr I'oniial icni, iicciiiiyiiiir tlic ]iniiiiiTi i>\' tlir \allr\ 1k'1\vci-ii I'wi-h iMiiilc and Mission iM-cck-. Tin' fdi-k* ul' i lii-> lurnia- Ti"in an- all (inly iiartiall.\ cdiisiiliclali'il. and iaMi.'r Ir litn- ^amlslnnr ilii<>ii::li marl an ai-<- - l rat ilii'd --I'ain^ .if liruwn li^inlic inalfrial. 'I'll nudonicralc i> niadf u|i o|' ^i'\ cral vari«'tic> ul' |iclililcs. ainniiLr « liicli tliii>c nl' L:raniiiiid diarai-irr. u liiif ijiiai-lz. and linn'sldMr arc cdnspiiMidUs. TIh' white i|narl/ i^ ladri' r]iii-iidns in tlic line than in the i-narsc ciiiiLi'liiMifraii'. Thc-i' ImmK ar rlainly nnccinrnrinalilc with tlir iindfilvinu nnU- alreadx ilocrilicd. Olili r •jfiirils. — On the riyht liaiik nl' .Mi-.>i(in (frck. at >c\cral |Kiiiits lii-twri'n Twch ciuiU' ami WnH cri'i-ks. iinti-rii|i> nl' ihi- Mack (•(laly >lal(' 'if llic .Missiiiii (feck >rric^. risiiiL;' In a lr\cl nl' n nr '.' I'.'ci abfivc ill'' |iri'>cnl Imd nl' tin- c-iTck. ari- cajiiii'd li\ a thifkni---. nl' alxiiil ill t'iM-t of river ^'ravel. Tlii' material nf llie iira\c'l ranges frnm verv small iii-hhles ii|> In small Imuldeis. and lliede|)nsil seems evi- dently t(i ha\e lieeii laid dnwii uheii the ereek llnued at a higher level tliaii lin\\ . Whether tliesi' nider ^laveN are ;iinil'einiis was linl learned, .i iidirin^'. liowcx er. frnm theamininl nf i|iiait/,--eliisl wliieli lliev <'iintain. seemingly derixi'd fmiii the liirehCreek nr |-'nrt,\ mile scries, lliev pnilialily earr.\ at least snine ;^(ild. Yiiiiiuii r (/i-'iri Is.- -'\'\\v ynnnii'er irra\els. niw dis]i iseil in ii-rei:ular liars and riiiarian de|iiisits Ifnni 1 In ."i ni' i'. feet in tlpekness almiir llie presi-nt lied of the creek, are made np in varyiiiir prnpnri inns nf liiaterials derived frnm all the aliii\ e-nnled lied-rn(dre not found in place and which prnlialily occur farther up in the heads of the ■rnlehcs Inward the divide>. 'I'hese iiravel deposits aic t liird;er and liner in the lower part of the valley, while ill the middle and upper jiart they are rather i-oai-se. and in the ^mUc-Iics consist larLrelx' of liowlders. .Ml alonir Mission (feck and its liranches the travels have lieeii found liy prospect i Hi.' to carry .i:'!!!!!. At the time n''\isit (.Vuirust, is'.ic.) some work was lieiiii;' done on 'rwehemile (feck and son n r.oulder (reek, hut the only diirj^dnirs known to yield yold in payinir ijuantitv were on .Vmericaii I'reek. ahout 1 l' miles ahove its mouth. \\n,UM AN I HKt;U. /,'. ,/.rv,r/,-.v.— Ameriean Creek is a hranch of Mission treek and (lows into the latter stream a short distance ahove its mouth. .\hnu( :i miles ahnxe the pnint of .junction }.'ray shales, wlneli carry seams of coal and which helon;; lo the .Mission (feck series, chauL'e to uni- form i:rav-hlue sandy limestone or impure line--iaiiied i|uartzile. whieli hecomo iicai-ly iila wcailicriiifi, l)r()\vn. At llic Ippci Caiiyoii on Aiiu'rieiiu {'reck tliere (iciMir, licsidt'S tlic riuai'tzitt", iaiyf masses of rock consisliuj,' chit'dy of Sfrpciitinc and chlorite, in which an; rrajjnioiils of residual olivine. This rock is prohably of tnfTaceous orij,'in, and both it and the asso- ciated iiii|uire qiiartzitcs and limestones have been described nndor tlie head of the Ham])art series. All these rocks are jjenerally mnch jointed, and often they ac(|iiiie locally a schistose strneture, althoufih without any remarkable devel- opment of new minerals. Along the shear zones tliere is a fjreat deal of silicilication, so that the rock is altered to a .jasin-roid, and alonj.? the crevices (jiiartz veins ])arallel to the shearing planes Inne been formed. Tliese shear /.ones aiH^ also often rusty from iron oxide derived from the decomposition of i)vrites; and often both c or I.t feet wide. In the bottom of the gulch are fragments derived from the dills above, nearly angular or slightly rounded in shape. These fragments are almost exclusively of the iripure quurtzites and ser- pen! inous tuffs which have been descrioeo, and also of the (luartz veins which these rocks cinitain. This deposit was, wIkm'c observed, 3 or 4 feet thick, and was nearly barren, all the gold being found on top of the bed-rock beneath. At the time of examination only one claim liad been opened on this creek, although considerable active i)rospecting was being done. This claim was that of ^Fessrs. Stiles, Roberts, and JUishnell in what is called the Upper Canyon, on account of the contraction of the valley at this point. Here the gold was found beneath the gravel on to]) of a zone of schistose impure (juartzite 3 or 4 feet wide. In the ujiper part of this loo.se decomposed rock fragments of gold (jccur abundantly, often of larg<» size. In shape tliey are generally irregu- lar, sometimes rounded, and lie in thecrevice.s of the schist, so tlmt the coarser pieces are picked out by hand. (Some of these have (quartz clinging to them. In the separation of the gravels in the sluice boxes many i)eb!)les of magnet it«^ and Itarite are found. These are well rouiuled, but are often of considerable size. Tliere seems to b,-* little doubt that these minerals as well as the gold are derived from the schistose zones iu the bed-rock. At the tinu' of the examinati(m of this creek the first clean-ui) (i. e., the draining of the water from the sUiic^es and the collection of the h USGtOLOGICAl SURVEY EIGHTEENTH ANNUAL REPORT PART Hi PL XLIX MAP OF A PORTION' OF BiRcii ckki:k ALASKA F'rom Truck Surveys by t'. S. Survey Party in charRe of J. K. Spurr S, al.' 11 -. Ill r. ^1 Mil l:^ '■• CirclfCilv Contour Interval 500 feet Datura : Yukon River ivt Circle City Approximate elevation 575 feet above Sea Level Tbc ri*cl«Hgjiivr Br--a lin ioifA iu tiiwtiol liiira Iniilrati-a X,^ tbe mluln,! diutrirt alu'Wii on ft lar^«-r if ftle on l>Ute I. ^.--^ Housi' ,• -' ^ -' An, 1^ ' JPi 'r'|i4"W'ff"i's>' " ^MnimiiodiHniLsf ' it:':,. ^ ^,>-'- ) / ■ J 1 ' ;/1WU -^^uio .N ..^:>*J^ ^ .~^, H •™"^T m III i ■ ■^'S f ' !* 1 ':4. ■ r li'i' 1 ; i ■ flS ( is i' Lr •' 'I SI' f 11 II.] OUl.cii ii|(ii,iN(.s: iiiiKli I i;i I'.K. ;!11 He]iiir(il("l pilill liMil ,iu>l hciMi iMiicIc, and iln' ii'--iilis wire kJ7 jiiM-ilay to cacli man workinjr, cir. as is (■oiniiKinly saiil in I In' ininiiiLT Yukon alicut^ 170 miles below Fortyniile I'ost. Tlie actual niininj,' Yukon. The (list rict includes a luimlier of ^'nhdies, all of which How into Birch Creek, and extends over an area of Ion of I."iOs(|Uare iniles. Tlu' aci'omiiauyini; iiiap (I'l. XM\) shows the i,'eiieral course of the streams so far as is known, and the jreneral topo;.n'apli\- is iiicjieati'd by cont miles wide in jilaces, runs across the district in an 'cast-west direction, iipi)earini; on llotr'i'in and I'loulder creeks. It is clearly intrusive and has not been sheared. In some places are small aplite dikes, and often r. and i'orinipine li\ 11. I!. (Joodrich. iiik;i.\i ott hi:Ariv\ ihiii (;r[.i ji. Rl-' I ilou'cm (iiilch received its name from the fact that the discoverer trie(l to hold a larire part of the richest dij;j;in,iis, lakinj,^ up separate claims for the whole of his iiiimcroiis family, and, it is said liy some, for lictitions peisonap's. When other miiiiMS came into the j;uk'h ami a mectin.i,^ was held, anioni; other tliinj,'slhe iiuestion of iiaminjj; the di^^riiiirs came up, and one miner siijiirested that. " Ilog'eni '' would lie appropriate. This su,u-,u'est ion was not ollieially ailopted, and tho iiami' head wood was i;i\en tlie;;ulcli as lieiiiu; nuire di^nifKMl, liut tho oriL'inal nicknaine has persisted and aiiKiny; most tif the miners is usek and has a total li'iiirth of aliotit i'. \ el V >liM'|ily, wliili' I Iw ntluT >|(i|ics .nnri' uiMit ly iiml li:i> ,1 ucU-tiijirki-il .--lii'ir 111- liM raci>, wliii'h il|l|il•all•^ llu' \alli'\' li'Vcl at an caiTiri- Nlatrc Alxnil liallway ii|i tlii> ltiiIi'Ii, on llic rasl side, till' ;ri'anilc licil-i k lia^ ]u-,-\\ iTiidrd xi a- m lra\ r l«n liiu'li piiinai'li's, wliii'h >lani| iini' uii each sidi' <>( a liil>nlai\ l.mi11.\. riii-x' liiniiacdcs liirni a ciiiisiiiiMKiiis ami ^iriUiiii: iVatnrc in iIh' liiiiiii;ia|ili\-. and pi l)\ llic naiiK' of llir |)rad\v I |lnlli'>; and I licir (•\i>Ifnri' is of itself snllicirnl ex idi'in-o lu ciinlniN rrl llic idea liial lid- di-lfici lias I'Nci- iinilcrjjiunc any cxiciisivc fxlacial ion. /,r(/,- niailr I'.p of -ulianiinlar dl' slijrldy Worn fraunnciil-.. roiisislinu' mostly of schi'-t-and ;:n('isscs, witli some iiranilc and vein unarl/; and tin- material show- sotni' slinlil arfanu'i'iiKMil in lioi'i/ontal layri's. as if fi-oin tlif tIVitIs of watiT acliiin. 'I'lic naliiri- of this material shows that it has Ween lnoiiirht down fi'Kin the nciiihliorini;- nionntuiiis. and since ije'ie is i.\ iilmee of nil extensive jilaeiation tiie ai;entsof t ranspoitai ion niusi have lieeii tin' small streams wliieli llow in the j^nlelies. Tiie ei,nalile arrange- ment and distrilintioM of this stream jrravel or torrent ial detiilusiii the broad valley of ('l'ove the limit of walerlaid torren- tial nuiterial are of <|uarl/.itic schist carryini; quart/, veins. ,\bove this is a belt of .^i-anite :.' or :> miles wide, 'i'his .iri-anite is massive, and shows no sliearini; m- other alteration, ami so far as observed oontains no ([uart/, veins. .Miove the u'ranitc Hie rock consists of (|iiarl/.:tic and inii'aceou..i sidiists, whiidi ai'c appan^nily in laru'e part metaimirphosed sediments. In one place a darker, s(diist ell:. ;{44 (il",()|.()(iV nV TllK VI'KOX .ioLD DISCKICT, ALASKA. 1 m "if i ■ y ..- If; }i )' if 31 ;;iii m llciiri' till' ^riiiiiitc is Idokcil iipciii willi (li.slavur l)y tlio iniii. tliiuiu'li tlic liclicNl (lijijrinjrs arc s.iiil In (tvcrlic the contact of granite and scliisl. Al tills conta<'l. liic j,'()lil is coarse, as it is in tiiL' ili;,'gings farther up. 'i'lic most i)rolilalilc u'ravcls arc fonnd witliin a distance of t or .■> miles from the irranile licit up tlie lmiIcIi, hut in the \ipj)er jiarl of tliis(listan<'e tiiere arc often plai'cs in wliieli llie i;oi(l is scarce, although in neighboring claims it may In- ])rcscnt in eonsideraltle (juanlity. \\'hen the gold is thus unc(iually distril)Utcd 1 he gravels arc known as "siiollcd." T'or a distance of .! or 1 miles at the \-ery head of the gulch the grasels arc not worked. 'riiroughout this gulch the barren gi'avels wliich lie on top of the pay gravels are coini)arativcly thin, being from :j to 7 feet thick on the average, so that all claims which show good prospects can be worked in the summer lime, and there is little winter drifting. On .soiiii' of those claiiris, in the sumiricr of Is'.m;, the ilail.v products were often as much as -2 or :! ounces of gold to each man working, or, as is locally said, - or-'! ounces to tli(» shovel — that is, liie ipiantity of gravel which can be shoveled by one man into the sluice bo.xes in one work- ing <1;!y of ten hours containccl on the average 2 or :{ ounces of gold. Where the gra\'els overlie the granite there is much of this rock associated with the other fragments, bnt above the contact of granite and schist tlici'c ari' only schist and fragiiieiils of \ein materia'. Th's shows that the gravel is derived from very local sources, and that its rotite of travel is constantly down the gulch. .Vmong the fragments of veins ar(! many which are rusty from the de«'omposition of sul- l)hidcs, and .some still show pyrite, and occasionally gali'Ua. Otln-rs are remarkable for <'ontaiiMng feldspar nd.\cd with thc<[uartz gangue, anil these veins contain pyrite in tlie same way as those consisting ent irely of (piart/. Ill the richesti diggings the gold is geiKM'ally coarse and greenish yellow in color, and the shape of the grains is generally broad and Hat, which prevents their traveling very ra[)idly. Pieces containing gold to the value of «."> or sKI are common, and the largest nugget yet found is said to be worth *Sl'. It is i)robable that here, as in other gulches, the gold is chiefly associated with the i>yrite which oe especially abundant in thi' schist near the Contact with granite, and this locality is considered by the miners the richest 111 the guleli. The comparative barrenness of the gravels over- lying the granite, and the fact that tiiis rock contains, so far as observed, no ([iiartz veins or thickly disseminated sulphides, also point strongly to til is origin. At Hill's Koad I louse a specimen from IIog"cm (tiilch was seen which was about fmir-liflhs (piartz, the rest being gold wliicli formed little reticulated veins, so that when broken out it liad a leaf-like or x)laut-like form. This form is roughly like tiiat of n (U i.( II i)i(!(iiNi;s: i\iPi:i'KM>KN"CK ('i;i;kk. ;ur) all llii' ciijir-i- Licild I'diiiiil ill llii> iXiili-li, as «fll ,i> in iii..>l ul In-i-- of tills ii'u:iiiii. (iali'iiais I'liiiinl in sr.iall hnu lili-i> in tin' u'l'axfU ami in snialli'V grains in tin' coin-rnliahMl dn-I uilli llii' l'i'I'I. 'Hi Malim's claim, which is one uf the mosl inmlncl ivi" cm tlic ,i;ulcli. a laiircxcin nf galena, which Innl part ially allcn-il ti> IcaM carlMinalc, wa- I'lum! in the hcil-i-iick beneath 1 In- i:ia\ els. 'I'hi-. vein is said tn lie cunt iiimins. ami an assay id' a small samiili' made in the lalMir-atuiy c)t' the SnrM'V showed 1 I (Minces (iT sil\ cr. Small liaL meiits uf native lead lia\ i- also l>een found in the ^navels. «,lu;i.Ml«»uN line M. (ireenliorii (iiileh is se|iaiated ffoni lloirum by a low n.otintaiii s|inr. It is vefy short, and soon unites with otiiers to fuiin I'.oiihier t iiilch. At the lime .t. was workiii;,', altiioii^di till- ^n-avels have been sliown to be comiiarati\ely i-ich in plai't's. 'i'lie .hief liillii-ulty e\|ieiieiic.'cl here wa- the lacli liuces ami separate the ..'old from tlie irraxeU. On thisi^iilch the chaiacterof the rock is preeis(dy similar to that of the rock on Hou'i'iii (iulcii. The ^riaiiite belt ses liowlder ( reek below the junction of (ireeiihorii. The ;_'ravel- on (>rei-nhoin an- thin, and the dii;-,i;in,iis ciuild easily be worked if there were a snilicieni -u|(- plv of water. The hiru'est nnu-el I'oiind on tiie irnlch so far contains s.M worth of ;.'l|o"> M.me dis- tin<-t variation;, from the valleys of I'.oiilderaiid lIou'"eni. farthereasl. From the head of Imlepeiulence the sloI)e up the divide is very steep. and the Tiumeroiis small foeders which llow down this slope have carve(l valleys milch less eo!isi>icuous than the corr<'sponiliiiu' f leis of iIm' ct ks.jnsi meiilioueil. In this way the hea^l of Inde|,endeuce Creek, as lonipared with that of Ilo-'em Creek, shows a markd tend- ency to assume th.' form of a .-if-. tie. In cross-section Independ.'iic-e Creek N'alley also shows some sliLrhl variations from the type repre- sented bv the valley of ll<.:,''em Creek, for althoii-h it i-. like the ahov-mentiom'd valley, ron-hly V-sha|)ed in -eneral ..ut lin-. the bot- tom .if the V is more rounded. This wideiiini.' of the valley. ,ine of no ineonsidorablo ini|iorlanee. When we come fo consider the cause of the comi>arativoly slijjlit did'ereiice between IIo','"eni and Independence creeks, we not<> that the,- run neai'ly jiaiallel ancl are at no j;reat distance a[)art, l)ut tii.:t Independence heads in a considerably hi;:h(>r ])oi'tion of the divid''. Wlien these creeks were exaniineil, in the month of Auiiusi, liiere wertMMUisiderable masses of ice on the ste(>|) slopes at the heail of Independence Ci'eek, but uoni'at the head of Iloii'em. 'i'his residual ice was presenf not. only on Imlepemlence, but at the head of all tlie ('re(>ks which rise in this hiirher portion of the ridire suri'ouudinf^ Mas- todon Dome. At several points in the valley of Imlependeiu-e Creek, i)articularly on the west .side, tli(>re are disliiict teri'aces at considerable elevations alioveihe present stream beil. 'riiesc terraces evidiMitly niaik an aiM'ient !o\el of the valley. (tnrils. — The nrav<'ls are identi( in nature with tliose in other frold-bearin.u: u'ulches, beinn' made uj) of little-worn, slii^htly assoi'ted, an};iilar or subauiriilar frauiiients of schist and of vein <|nai't/. inter- in initled with liner material derived from the decomposit ion ami al»ra- sioii of these I'ocks. .\t the I imi' of \isit t he yulch w;is not WiU'ked for several miles below the head, the chief claim workini; beinjr mdy a sill Ml distance abo\(' the juncl ion with Mastodon (rei'k. M I his point the aciu.il width of stream elo\\ I he mouth of Independence (reek lli{> bed of Mammoth Creek widens \('ry rapidly. .V short distance bidow this point a pay streak lias iiecii worked on the left siib' of the \alley, some Jim feet or more friuii the present channel of the sticam and on the oi her side of the \alley. Farther down llie width of the ,m'a\els ^rous so yreat tiiat local iuu: the pay streak bi'cimics very dillicult and little miniiii; has liecn doiie. The nearly Hat bottom ijraxels become wider and wider, iner.uiim into the bi-oail plain Ihrouuh which (rooked (reek Hows, I^I'IIIK,] (ai.CH I>IGGI.VGS: MA>ToIl('N i Kl KK. ;;r ami tins iiitolli.- >till lin.a-lff tlai-<>r Hiicli Ci.'i'k. 'I'Ih' iiialiTial wliicli loi-iiis till- t...tt..iii .»t" all tlii-><' will"- valleys i- ( >simiI iaily ili<- same, iM-iiii: siil»aiii."i'.ar frai:iiu-iits i.f schist. rti..ii~ i.f tlii> iiialerial are siillieieiilly am i'.enms 1(1 ie|)ay working: iiii-ier favmalile eoinlitiniis. ami on a the jiioiieer in the liirrli (reek ilis,.iet. as Franklin (iiili-li is on Fortymile. It was ilisi' ivered in IS'.ii, and sinci' thai time ha^ l«-en w..rke si;rii of exhaustion. The i;Mleh is lin miles distant from Cirole City, and is reached l..> a trail whieh crosses the swa-upy v:illey of Bin-h and ( rooked .-reeks in a smnhwot direction. The moiiniains in ^.'eneial have nearly level lops, sloping' aloiiL' tlie di]) irently toward tli- -oiith. Kv.-n the hi-host points are fioneially cov(-i-ed with nio». and the L'ai's or holh.ws an- l.oir-y and lii.ed wiih little ponds. I'.nt aln.ve thi^ lal.le divide are oc<-asioiial lieaks which have received, from their rounded and prominent summits, the name ". which are namd res] lively Mastodon Dome and Porcupine Dome. Tin- lormer has an ele- vation of 1. iL'i' feet alHive itie>ea. a- 'Id ermiiied 1 .y aneroid harome- ter. while the latter ri>e> s.,m..- J<-" feet hi-her. Ind.-r Maslod,.n Domehe.i.l the watei>of (;ohl Dust and Ka-le. tluwin- .lireeily into Kirch to the west: al-o the North Fork of Ilarrismi, which tak,-^ a lonirer course and, with the South Fork, enters IJircli (reek i-'n mil.-> to l"iie southeast. Mast.Klon Creek aKo has its s..urce here in three heads, an.l. llowinu' east of north for IJ miles, drains into Mammoth Creek. The topoirraphv of the IJahl Mountains dei„-nds to a ,ii:reat extent upon the -eoloiric stnict.ire. As remarked above, the slope ot the mesas is determined l.y the dip of the rocks. In addition there an- lines of weaknev, atVopled by joint planes «lli.-h illteise.t the sehis- tosiiv at hi'di anirles. Ahm- the^e lines frost a<-tioii l.ivaks down t he ro.-ks and the divide is rendered unsymn.etrical. <>n the side oppo- site to the dip .■litis are pr.«lu.-ed. so that, viewed aim,- t he St rd.e. t lie dom.'S present a sharp, steep sloi.e toward the noiih and a lathei frradual incline toward the ~oiilli. \11 alon" th.- .livi.le. ind.-t-l. tin- sl-.p.-s to tin- Cr<...k.Ml Cre.-k .Iraiii- a.r',. svstem are mu.-h steeper than towanl liiivh Creek proper. The th,,...'f l.-rs..fthe main MaM-Hh-n (;.ek head in ampint heat rnal .•}48 OKOLOnV OK THE YIKOX C.OIA) DI.STKICT. ALASKA. 'i w ! Ir; ■ W' „i. i ••a ijlil •H liiisiiis, and arc supplied 1)y many small stn-ains ^vliicli ilow from areas of snow, small patches of which still remained in the middle of Au^'usl. These streams pliini^e in small cataracts over jwrpendicular dill's and talus slo])es witii a fall of S>»> feet in the lirst mih'. At this point the valley assumes a U-shape in cro»->cction. Three miles from the summit another branch ciitei-s from ihexnith, its valley hein},' comparatively broaam direction. The moutli of this bramh marks the farthest extension of mininj; o[)eralions. From this jioint onward only the waters from small ;;ullies increase the volume, and the creek (lows with considerable itrade in a broadeniii^r valley from which the hills rise with slojK'sof about lMi . The ••hov'liacks." or dividing s])r.rs, are unlimbercd except ni'ar the mouth: their toi»s arc irem'rally smooth, but arc interrupted by ledf^es. Util-i-dcls. — The rocks are mainly micaceous quartzit<'-schists, some- times t;iapiiitic. There aro two sets of jointing, one especially well- imirked, forming an angle of .SD ' with the i)lancs of schistosily and striking north-soutii; the other, less well marked, intersi-cts the .schis- tose planes at the .same angle, but also forms with the noi'th-south set an angle of 70°. Ity these joint plane.- the rock is split up into rough rhombohedral blocks. The strike of the ro<-ks foi' tli<' whole length of Masloed-rock, ^l to the pan. The gravel is geiu'rally lliickiu'ss makfs sliovi'liiii; inln lln' imxi'i'. cspi'iially lianl wiirk. ami on smiu' flaiiiis tlic slmvcliiiu i^ iliim^ liy slairi'S. t 'iii' «<'t nearly donbli' tln' iiiimiImm' ii\' men llial an- •■niiiloyi'il in shallow iliiryinirs. Imt ilic rcsiilis liavi- paid. TIk' mail-rial in tin- liarfcn and pay i,'ravcl licri- has thi' same ihaiac- terastliat in other parts of this district. The bowlders arc ill a-soried, of hical origin, and sliow little evidence of traiisportal ion. .\ mile and a half above the month the :J feet of jiay dirt is overlain b\ t feet of se into the valley of Miller (reek. The dip of the rcM-ks all alon^' this dividinir si)ur is sliirht and toward the southwest. Its summit is almost flat, but is broken by north-facinir clill's iiito a series of soutliward-slo|iiii,i:- steps or benches. .Vt the vi-ry end of the i-idL'c the actii(ni of the three streams. ;Millcr, .Mastodon, and .Mammoth, has izone so far that a svminetrieal cone of erosion has resulted. The valley slopes of Miller (.'reek near its mouth and for :i miles alKJve are ditl'crent on either side. On the northwest they are com- paratively steep, with an,i;les of about :iii , and sometimes, imne emphatically nearer the mouth, the creek undercuts its banks, form- iu:: bluffs of liari- rock :.' • l'."> feci lii!.di. I'lMin the southeast side, .'),"ill (ii;i)l.()r.Y OK THK VUKuy (H)LIJ DISTUIC'T, ALASKA. :'p' (Ill il ilicr ,i:iriil. ilicic :s a >]i;:lii iciiari- hikI m LTcntli' nsi' (ov t'loiii (»iic-((iiiii-t<'i' 111 iiiicciirlilli of a mill- i<> a pipiiil when' tlic hill rises steeply. The Icrraee is rciiiiied in iri'avels. which iiave since lieeii cu), hyihe creek neai' its iiiiiIMIi, fofniiniT a irol'ire I .") feel deip. AlollLT llie hiwer |H(iliiiii <<( Ihe stream the valley is narrow ami V-shaped in cross-section. Init iri'adnallv . iri asi'endinir. the sides heconie of mkhi" e\en slope fr'orn the tops of the rid;;es to Ihe erode lied. 'l"he iriax'el also thins out aradiially. until, at a ]ioinl -J miles from the divide, if is almost entiiely alisent. I'mii- miles from the month a branch enters from the southwest, whose source is in a Hat, lioi;;,'y iiiip in Ihe l>onan/.a !>i\ide. Tiiis liraiich lias a very steep urade and Mows lhidn;rii a V-sliap<'' miles fro.:' tiie mouth. Here the pay .streak was \ feet thick, ninler s feci of barren ,i;ravel, and yiidded IJO t'cnts to the pan. \\ the time nf our visit :i men were siiovidintc into the lioxes on tliis claim, and above Discovery :2.-| men were work inu; up lo within I'.l miles of tin- di\iile. The area miw lieiiii; worked is eompriseil in the middle f miles of the valley, above which is the tor- rential portion of the stream, from which the irold-bearinn j;ravels have been washed away. 'I"he j{old here is much liketnai found on .Mj'.slodon, occurrini;' in sinail grains. Tliere is very little tine iruld and no larjfe nuf;j;e's. Tito sliaiie is tiiat of Hat scales, little worn or roumled, sliowini; an orijiin evidently not far distant. I'MIMri'lM; iUKKK. Porcupine ("reek is tin' true liead of ('rook(>d ("reek. One branch rises at Porcupine Dome, whence it Hows north of east thronuh a liroad vallev, with an average fall of loo feet per mile for !•". miles. Oncll l>Ii.(;iNOS: I'OUrll'INK ClIKKK. h:a It is llicii JdiiH'il liy Maiiiiiiiiili Creek. an(i|iall/.;i Creek. «liieli is ■■ miles loiitr and llnws iiar.illel uitli Millei- Creek, from w liieli it is :l miles ilislaiit. heiiiu: separateii '>.v •! tial. leil^v riilL.'e. Tlie valleys ol' l'i.reii|piiie Creek ami its liraiieli. rioiiaii/.a. are wide, espeiMallv Hear t lie heads, jilid the (•re(dt fur the last ei;:htli or si \teeiil h of a mile t'rcnii the(l■e(d^. ulieii their allude is iiiere.-ised. sometimes to r.i i . The heads of i| reeks them- selves ai-e sleo|), ami there are lre(|Ueiit clilfs, liiit the t rue eirijiii' is ilhsonl. Tlic mesa is |ierha|is hetler marked ii|ioii t he ili\ ide alom; tliese lieadwalers than aii.v where else in the I'.ald Moiiulains, 'I'lie (li|)nf the roidis is sli;;lit heie. and iTieai table tops, one of them nearly fireiilar and a mile in diameti^r, are seen. To I he soiithwesi, alonu; tlie dip. they slope very trradually into tiie vallex nf Hindi « yi'^'k. w liile OH t tie other side the descent is Vel'V steep. l'"olir of I liese tallies, u il h Hat traps l"li to I'on feet (rolled between, are crossed in u'ollli;' from Miller (reek to roicupine Dome. ,ill reaidiliitr to a nearlv nnil'oini altilude of aliollt l.tilin f.M'l. Two years au'o a few men pmspected both i'oreiipine anil I'.oiiaii/.a, hilt obtained niisatlsl'actory results, .'i cents to the pan beiiiir aboiil the laru'esl prospect, itii a nut of the width of the valley il was very dllVicnlt to locate the iia\- st leak, and the thickness of the ura\e|, from 11' to lA feet, was also a hliidranec to workinu: u:rav(ds « hich did not promise excoptioiially well. So it was soon abaniloiied and has not been invest iuated until last summer, when one man visiteil it and was at work at the time of oiir visit. \\ the mouth of I'.oiian/.a » 'nek tlie section was as follows: Sii-liiiii lit llii' iiiiiiilli iif Hiiiiiiimi Cnil: K.'.-t Veget!iblo iiinlil ami moss Siinil. scniistratiticd. L'oiitaiuiii,i,' a tow iiclilil.s from t to :1 iiH-lics ill iliiimctiT (Travel. ooiitaiiiiii,\' heavy suban.nular liowlilcrs of (iiiart/.iti sehist . to llAlimsON IHKKK IFarrisoii Cn'ek is one of the lar.iiest st I'cains of the IJircli Creek dis- trict. It is most easily reached by trail — up Deadwood (iuldi and thence southwest over the divide. The iipiier part of the deck divides into two forks, of which the North Kork is the h.imer, headini: np under Mastodon Dome, and at about 7 miles below the forks the main stn'am (lows into or iiiiiles with Kindi ( n^ek. At the iunctioii of these two stn'anis is I'itkas I'.ar, when', in 1m':S, uold in the HinOi Cl-eek distfiet was tiisi discoven'd. The lirst irold discovered on ilarrison Creek was near the head of Konh Fork, alxnit a mile below Mastodon Dome, in ls'.i"i ( .')• 'I'll- [I'll m'. itirf ■ i ;! )- ; f .'5'iJ (ii;i»l.i)(iV OK Till', Vl'KON fioM) DISIUK'T, ALASKA. Civck is, llic'icluiv, niic> (.r the lic'wcsl n{ tlic Ui rcll ( 'reck plil • ilit;- Him;s. I'.cl'.iic lliv initlillc >>( Aui,'iis|. is;ii;. Iiowi-vcr, llic wliolo of the Norlli Fork was sl.ikcil nil' in i-l;iiiiis cxtciidiiij: roiil iiiiioiisly t'nmi near the foot of the small liiiiicrinj: ••>,da<'i('r" wliicli (Ijiiikstlic Dome down to near I'laniiai.';ui (Jiili'li, inoic than a mil'' liclnw tlic forks. riacor (li the southwest, but near the Dome, aiip, while the north slofie is more ;;entle. This feature lias already been noted in the east and west ti'endin;; ;rulclies of l''orly .Mile dis- 1ri<'t, where the dilTereiice of slo])e was attributed to insolation and tiltiii;;. In this case, however, the attitude of the sehistosity is fax'or- able to the development of a steep face on tli(> south, and is probalily an iiiiportani factor. In looking eastward it is seen that the steei) right siile of the upper portion of the valley does not conlinue along the stream where tliis turns lu'arly at I'iglit angles and runs toward the south, but is in direct aligiinuMit with an e.seai'i)ment or ridge formeil by the u|)turne(l edges of schist, which climbs the divide between Harrison and Deadwood gulches. (7/-(nv?.v. — The gravel, so far as ol)served,consistsof material dcrive(l solely from the (|uartz-scliist series, and the fragments are generally coarse or subaiigiilar. This isesfiecially tru<> of the middle and ujiper parts of the North Fork. The width of the gravel varies fi'om less than 101) to over IJOb yards, the maximu •cui'ring usually at the inoutlLsof the pups. Sometimes also, at the mouths of tlie jMips, usu- ally on the lower side, e. g.,in the great lieiid of North Fork, sheets of soliil blue ice, covering the gravels for some extent, linger throughout the sumiuur and prevent or interfere with mining operations. The J 'i KriKH.) GULCH DIOGINGS: HARRISON CRKF.K. ;;;j:{ deposits of gmvol bfupiith tliis ice are Buid to l)o tliiii, l>ut sjrciii>rally to yield good imy. The vortical section of the gravels varies in dilTereiit loealilies. Four or 5 feet of gravel, overlying several feet of clay, which in turn restson bed-rock, is probably u fail' average. iSelow tiie great, iM'nd of \oilh l''ork no excavation has yet extended deep enough to expose a complete section. About liiree-(iuarters of ii mile aboxc the forks, liowcver, "> feet of gravel iiad been passed through, and the iiiineis expected to [pass through ."> uy (1 feet more before reaching bcd-roeU. About a mile above tiie l)eiid. wluM'c the fall of the creek is rapid. 1 he section consists of only :i feet of gravel, resting on rotten lied-rock. 'I'his rock is a deeoin posed micaceous (|iiartz-schist, traversed by ((iiarl/, veins, (iood eolors of gold were seen (piili^ near the surface of liie gravel, as well as lower down; anil the yield on claim .">:! is rejiorled to be betler than was exiiected in these thin gravels, one nugget founil being worth •'how ihe gi;i\el to be underlain by several feel of yellowish-brown clay, 'i'lie clay is tough and 1cnaci(Uis, and its stickiness is said tobeciiiitea hindrance in the separation of the gold, which here occurs almost entirely in it. It shows some leiidency to stratilieatiiui and often there is some (piartz gravtd. The fact that it somewhat r<'seml>les in places line Ixiwlder- clay, and its occurrence at oik; jpoint ;!(• feet al)o\e the level of the stream, snggesti the i)ossibility of its being of local glacial origin, though at present there are no glaciers in this section i>( the \alley to which it could l)e attributed. If of sedimentary origin, this jiortion of th^ valley must have been temporarily occupii'd by a body of standing water in whicli the clay was laid down. The most i)lausible \ lew for the conlineiriciit of the water is that of a landslide dam thrown across the gulch at some nar- row i)oin( below, though no remains of such dam were obseiveil. After the lakelet was draineil of its water the gold-bearing gravels were deposited above, and the gold worked its way fnuii the gravels down into the clay. A third view is that of residuary .soil. This seems plaiisilile encuigh forthe clay found on the sh>pesal)ove the creek, but no such residuary deposits have been observed elsewhere in the ISirch Creek di.strict, and it is ditliciilt to .see how, in a gulch of its own cutting, a stream should be able, for a stretch of -' or more miles, to deiiosit its gravcds on residuary soil. As other claims on the gulch are opened up, fur- ther excavations will doubtless tlirow more light on the origin of the clay. Source af phwt r (j<>hl—\s in the gravels of the Fortymile district, so in those of Harrison t'reek some of the placer gold is found in direct contact with (luartz aiul (luartz-schist, showing the country rock of the region to be the source whence the gold has been derived. The 18 GEOL, rx 3 li3 ■ f| U' •ti i: >, I 1 1 3fA GEOLOGY OF THE YIKON 0OM> DISTRICT, ALASKA. iK'st fxaiiipli' 1)1" Kold-lM'iiriiijr qtinit/. fduinl in tlio {jravols is ii rlidin- ])(>i«lai l>li)ci< (if i|iiiirt/.-scliist,al)<)iit 1} liy^ l.y.'inrlics, fdiiiid on claim !M, iin Nortli Vnvk, aboiil liircc-iiiiarli-is ol' a mile above tlisulte(l in the jiayment of hljilicr wa^res on Kaj;lc (reek, tlic rates here beini;' >*\-2 \n'V day, while in most of the other irulches they are ^Id. Tiic points at which claims have been best opened up arc on ,AIas- todon l''ork, on claim No. J, .just above the forks, and on claim \o. 7, about a mile below the forks. M the former locality some of the ground is reported to have yieldeil xCl fo the shovid. The normal Vertical .seclioii of the placers as shown here consists of i) to S feet of frravcl, coar.se and tine, overlyiuf; Ii to 4 feet of clay, which is in other places seen to be distinctly stratilicd, and therefore of sedimentary orliriii. The clay in turn rests ld occurs chlelly near the top of the clay, some nuifn'cts liehiif found on its \ery top, lieiwcen the cla\' and the ji'ravcl; and with descent into the I>iwer Rniu|>ai'ts, .")ii miles licl'W \-\iv\ Ilaiidiii. Tiiis creok is rar;.i| mi tin- (.'oast Survey eiiart tlic ljiily known in Alaska l)y tli(> naino );iven above. .\lthoii;;h this n*^oii is a lon^j distaiiee fi'oin tlie liireh Creek district, yet it lies in th*- n<>rth- wcst-soiitiieast-treiidinfi j;old l)elt. which includes all th»- 'listricts tiiat liav(> been descrilx'd. F(jui' niiles alioNc its mouth Mynook (reek divides niin t»vo branches — M\ nook jjroperand Hunter Creek. A >Iiort di'>t;ini-i- alxtw tliis ]ioint I. itlle Mynook Creek enters. Tlie ^.'ravels ali>ii:r lh>- main creek are undoubtedly auriferous, liiit ouat.'couni of the width Mf the \)ille.\' over wlioso bottom they are distriliuted the pay str»-jik isdiflitnilt to locate. It tints happens here, as lui Kortyniile Creek and liireh Creek, tluit little luiniui; is done alouir the main stream. and nearly all in the V-shajied t,nilches of small tributaries. In these thebotlmii is so narrow that the pay streak, if |)resent, c.;:) oi'dinarily l>«'ea.«.ilv loi-at>-ilt~«-.in- taininj,'' fossils of liviu^r siH'cies. Above the silts, coverin;: ilie whole l)lateau, are iiravels of varied orijfin, which roll down tin- sHi-p hill- sides into the valleys. On most of Mynook Creek pn.i».-raM'l of the tributaries which have been e.Kamined the chief !>»-il nx-k- an- the diabases, lull's, and shales of the Hanipart series. It is prolMbie that on the upper waters of the creek rocks of the Bireh Cr\H-k »r Forty- luilo, or both, occur, but these portions were not seen. ii ..;< •? 3'i6 OEOLOOY UK THK YUKON (iOI-D HISTRH'T, ALASKA. KKSCHIITIONS OK lll'LCHES. I.ITTI K MVMMiK I'HKKK. VtiJlti/. — At itsjiiiiction wiili tlu' main sironiii Little MyiuMik (reek f«rnivfls narrow to .lO or In I'li't or less. AlHtvf tliis li'vrl ImiIIoiii on out' side is ;,'cin'r«lly a sleep rock wall, while oil the other a ;.'enller tains slope for 10(i feel or more, and then a >te<-ii wall ei)rn'spiiinliiiir with that on the r)tlier side. In general .shape this and ilie iici^'lilMirinj;;;iilehesaie likethoseof I'nrly- milc Creek and otliir sinaiiis in the gold distriet, luiviiif,' steep, liigh, and oficii ]ireeipitoiis walls iiielosiiii: a V-shaped valley which heads abruptly with a sifcp wall up to the divides. In the smaller jrulchea tlio streams How in xcritalde notches with no flood-plain whatever, while in the larjier ones tin- valley is naliiially soiiiewhat widi-r at the Iwttoni. The liea oes, and. to a less degree, the jijints and the Ixilding jdanes, atl'ird an ea.sy aeces.s to mineralizing waters, wlioso Work is shown by the formation of ])yrito and copper pyrite, and by the alteration of the neighboring rock to jas]ieroid by deposition of silica. These zones of mineralization are very common through the lower part of Little .Mynook Creek and on the main 3Iynook Creek alx»ve the inontli of Little ^[ynook Creek. There are also occasion- ally veins of white, crystalline (piartz, often with comb structure. (irnvtls. — In the bottom of Little 3Iynook Creek there lies at the surface a deixisit of muck and vegetable material, very black and full of i-oots. In one claim this material is S feet thick, but ordinarily it is oidy ii foot or two. Hdow this comes loo.se, dctrital material, con- sisting mostly of angular fragments which have slid down from the ■Pl'IIB] oui.cH hhjoixos: i.itti.k mvnuok ( ukkk. ;{57 hillside nliovo, many of tiu'iii Wcin;; vimv liiri;<', olii'ii ,i i'imiI nr mi in (liaiiiclci-. 'I'licsc fnifjjmfiitsart' unassiirlcil, the liiKMliii ami tin- lal•^;^< lidwldors occiirrim; to;,'«'liii'r. Mixed wiiii ilic-.- aiiu'ular HaLrmiMils, wliicli aro all derived fnim llie nicks of tlie l{aiu|iait >eiie.s tliat iiiMed smaller pebbles represenlin;; a variety of roeks, anion;: «liieli tlie ^niy inicaeeoiis(|iiait/.ile-seliistsol" the iSireli Creek I'oiinalion are con^iiieu- ous. Tliese rolled (Travels are most abiiiidant in I lie bed of the (ireseut Htroain, abovo th« angular doposit. At u iioiiit about a mile above the mouth of Little Myiiook Creektlm total tlii('kiie>N of Iho detrital deposit is about •! feet. Tlie bed-roek below it is so imieh disinte;;rated that it breaks into very small fra;;- ments, and so eaii be ter part of this bench is composed of ^Travel, which avera!,'cs 15 feet in thickness. The creek flows alony; the north side of the valley the whole distance traversed, anil on this side the bank {generally rises insliar[>. i)erpen- dicnlar rock clilVs directly from the stream. When, however, the chann •! bends towa.d the south, awa.v from tlic north side of the val- ley, lie l)anks are often of ;rravel. sometimes as mindi as 1.") feci in thickness. Hiil-n>:ks. — Tlie bed-rock of Hunter Creek near the mouth is a coarse, ioostdy consolidated conirlomei'atc, containing: pcjibles oT the older formations. Tliis rock is the same as that seen alonjr the Yukon at the mouth of .Mynook (reek. A sliort distance up Hunter (leek the contrlonierate is succeeded by shales, lutTs. ami diabase of the Rampart series, 'fiiese rocks are much jointed, and alonir shear- zones are silicilicd and imprcffuated witii sulphiiles. Tln-y also i-on- laii' oci-asional veins of ((Uartz and caleite. (Inirds. — Tin' best-])ayiu,u: parts of the claim now lieiii;r woT-ked liave ficnerally been founil at the southernmost parts of thi- meanders; that is, whei'e the present stream approaches more nearly it.s old cliannel. This is not. however, to be ict;ardcd as a strict rule, for jjtood prospects liave been found at dilfei'cnt localities upon the nortli niile. The i,freatesl thickness of the jji'avel is I.") fc<'t. Its |>ebblesare not (jeiierally larije, and it bears the same <'vidences of liaviny; l)een laid down in comparatively swift-runniiifr water as the }.'rav(ds of tlio of her districts: and tlie sann- slight stratification and illy as.soi'led I'har- aeler ol>fain. The jx-bbles, however, unlike tlio.se of tiie smaller gidehes visitetl in the Fortymile and Kirch Creek ilistrict, are of dif- ferent varieties of rocks. There is, of course, debris from the hill.s ininn'diately adjoining the lower part of the creek, such as pebbles of diabasic tuiVs, shale, and linn'stone, and th(>se are generally large and snbangular; but there are also wcll-ro'.i'-i'.i d sniallei- pebbles and bt)wlders of the typical IMrcli Creek fornmtion. i.uartzite-.schists. and schistose granites, with vein (|uart;:. The Mireh (Jreek series does not outcroi> in the distance travcrseil on Hunter Creek: and tlie fact that the material derived from this fornmtion has suffered greater abrasion than the other bowhlei-s is, in rrr : I fprRH.] Gl'LCH DIii(;l\i;s: KIuXDIKK DISTUICT. ;{5!t a iiicasurc, an iTuli'X i>( I'lirtlii'r 1 1'liiispcii'tatinii. Ai-cniiliii;,' in |irci;.|MM-t- iirs, the l)('il-i()ck Inr many miles ui) llic xnilli liraiicli i<( IIiinliT ( tfck is tlif sanif as that just tloscribiMl on tin' luwcr cn-fk. Imt tin- I'l'i'iiia- tion clianjjcs iieai' tlif lifaiis<-il of scliistiisc rucks. I'mspcctiiii: lias alrcaily r\ti'inli-, anil a <'crtaiii aiiioiint ut" pild lias ikm'Ii I'lmiid tin- wlmlc ilistam-''. Tin- ijold for cacli creek lias certain I'hafacteristics ul" it^ own as to ^liape, I'olor. ami size uliicli (listin^fuisli it l"roiii tliat ol' anoilwi- eieek so well that an experienceil miner I'an tell at once the |>arlieiilar ;_'nleli troni wliieii a )xiven strain lias been i'ecovcre have yielde.l .-oarso "old in a small way for some time, but only a few men weic employed there until the latter jiart of Auixusl. ls'.»i. w hen ' lie .(iscovery of cs[>c- cially rich ^'ravels or. .iio {.'iilches of the Klou'liki- h-d to a rush and the transference of most of the population of Fortymile to the new- district. No examination of this district was ma le liy the I'niled States <;eoloi,'ical Survi y party, but, ai-cordin;r to reports, it is likely to be a rich pro'liicei. The rocks appear to belonfflothe schisioxj JJirch (reek and Kortymile series, and contain abundant ipiart/. veins, in some specimens of which free ^'old has been found. ri'l'KlI VIKiiN. (»n the Selwyn River, wliii-h enters the Yukon below Fort Selkirk, coarse uold occurs, and a number of men were .•ni:a;.'ed in prospectinj; here in the summer of IS'.nl. This river, in its lower part at least, Hows throiifrh t!ie ancient schistose rocks, whi<-h liere. as elsewheif, <-arry abundant fpnirtz veins. On the east side of Lake l.ebarp', .just b.'low the head, is a small creek which is report eYrKUK. According to prospectors, tlie Koyukuk yields }i;old along its whole length, and is said to have ])roduccd about ^.'iOjOOO. In places coarse gold is found, which, according to 111 testimony of several observant miners, is derived fioni congloinerales wiiieh are made up largely of (juartz pel)l)les. I'hese conglomerates are associated with sandston.'S, grits, and shales, and usually have a steep dip. Tliey generally form the bed-rock along that pait of the Koyukuk which has b "n prospeel<'d. ami, judging froui the note of Lieutenant Allen, they a ■• to be referred to the Kenai series. BAR DIGGINGS. i a: .•UA.NVKI! - I' FOK.MATIOX. Owing to the considerable grade of the gulches in the auriferous area and to the conseiiuent swiftness of the streams which flow thi-ougli them, it is only the coarser particles of gold which escape being carried away. The liner particles, unless they are sheltered in .some cspeciall\' favorable position, find theii- way fro.-i the gulches into the larger streams. The limit as to the size of the grain wliich is tlnis transported is variab'.e, depending upon a variety of condi- tions, such as the strength of the current, its direction, and the nature of the bottom over wliich the water (lows. V.iriations in these con- ditions are constantly hapiiening in the same place. Thus heavy rains or the mi.'itingof snows produce a largely augmented amount of watei', and under these conditions grains of larger size will be transjjoi'ted than in times of drought. It is a geiu^ral rul(>, however, that the \(M'v coiirs(> materials remain behind, n comparatively tine particles e.scai)e and are carried to an indetinite disiance — a distance which may be \ery roughly consid- ered as in inv(M'se I'atio to the size (tf the jtarticle. In tile larger streams, when the current which transports gold along with other detrital material sutlers a decrea.se of velocity, and lience of carrying power, some nmterial niaj' be dropped to the bottom, while the wate- (lows on more slowly and comparatively clear. It thus happens that in long rivers which (low through auriferous rocks or whose feeders (low through auriferous rocks there are at in*^ .-vu'r deposits of tine gold in gravelly accumulations. Such accumu' ■■ of detrital mat<>rial are known among th(> miners as bars, and when surticiently rich in gold to repay woiking these are called "bar dig- gings." Bars are formed wherever the curves of the channel are ^■1 ''1^ sriiiK.] BAB DIGGIXG8. 861 such that the currpnt flows off at a tanf:«*nt to the shore, thus in-odiu-- iiij^eiaek water ami ofteu backwater <>reUo l)auk. Thus tli ■ nmst i- iioints imme- diately below where a pronounced curve changes sudileiily for aiiot her. Fifi. it— DiaKTam •■? iii>-al r;v.-r. -ti'.winir a'-'MiinuluD'Hi nf Imi-M Sliglit concave irregularities in an otherwise straiglit channel also pro- duct' tin- conditions neccs.s;iry for tlit-sc dc|)osi1s. sinci- such iMincax-- itie.«will not ordinarily inlluenc the course of a niodi'ratcly swift current. Therefore experienc<-re.sent stream and llu'ir evident relation to the pivs«^nt currents. .Moreover, the gold-bearing gravel is nearly always coufined to the actual surface 8n.l ' 'lies in thickness from '20 inches to half an inch. When the.se bars i. ' I ])ractically worked out, and have Im-cii left untouched for a IV. li years, it is found that they have Im-cii eiirichcil bj' new accu.i. .'ions of gold, thus showing that th<- process is going on, even at the jn-csent time. Such baw can Im- workr.l only in the drier i)art of the sea.son, when the water is .so low as to expose tliciii; ami in some cases tliey can liewdrkears ar vcrcroi'css of con- centration of tile gold pai'ticies brouglit by tin- stream is carried on. It is evident that, ill tiie flood-i>lains of the streams there must lie many such aceuinulations of gold, whicli liavc been left dry by c1 aiiges in the clianne'. In tlie richest diggings, such as the Cassiar bar Itclow tlic mouth of the Teslin. buried bar-s have b<'eii jn-ospected and worked to a certain I'Xteiit, Init in other places they are not usually very [jroduclive, since tliey are by no means so easy to locate as the actually lorming bai-s, wliich liave so evident a relation to the present stream. In contrasting the formation of gulch dig- gings with lliat of bar diggings tlie former may be considei'ed as essentially residual, the <-oarse gold l-eing usually derived from neigh- boring sources anil the fine material having iM-eii washed away, while the bar diggings are essentially deposital. emisisting of the material thus washed away and carried in siis|MMision by the ciirrein ni'.iii a favorable o[iport unity for deposition is iires«-Hteil. After such depo- sition has taken ])lace an iiicrca.se in the rapidity of the current may extract the liner gold from these bar iliggings ami carry it on iiiilil it can find suitable conditions for again depo>iiing it. Such a bar, from which the finer gold lias been extracle«l, is partly residual in its nature, although inimarily deposital, and may contain gold consider- ably coiirser on tlie average than that from a neighlMiring bar whoi? the current is not so rapid. The fac; Uiat the velocity of the water is incessantly changing in any given Im-alily makes clear the com [ile.xity of the concentration of the gold particles in these bars and also explains tlio continual changes. In this way a given particle travels continually, resting here and there for greater or less jieriods, and finally lodging in a coiuiianitively permanent alxxle. The very fine particles wliich constitute the so-called " flour golil "' are so small and *rr««J BAH DIGGINGS. 363 light that they arc carried fur a frrcat distance, and sonic are loiiiid along the entire course of the streams and of oilu-r streams into ■which these flow, and it even seems hijihly probably tliat the moro minute particles readi tlic sea, where they may be taken into solu- tion by the sjiline \vat<'rs. It is a wcdl-known fact tliat. sea water invariably contains a certain amount of gold and tliat such watere have the n-rjuisite i>ower of solution. As an exiiiuiile of the distances which fine fiold may hi' carried in c«>n>iension by the wateis of the Yukon, anrs. 'rhu.- the dis- eoven' and ar mining that the latter is soon abandoned. In the suiiiiiier of 1*00 the few men workingwith cradles and sluices on Ihcbarsof T'orty- mile ('re<-k Comprised nearly all those engaged in bar mining in the Yukon di.strict. '■«7 n OriTKREXCES OK (iOI.l) IN HAKS. Fine gvild is found widely distributcil in Alaska. All the smaller streara.s w^iose bninches have been described as alTording gulch flen th(>v are strewn o^ er the whole surfaei- of broad elev.ited plateaus. From the extensive dis- tribution of tlle^•■;,'ravels and from the positions in which tlicy ari often found, it is clear that they can n«jt be ascribed entirely to river action; and this, joined witli the evidence of recent 8ul)nierj;enee, supixn-ts the ide.i that they are lar,.,'ely marine, or have been redistributed by marine action, alt hon<.di those which luiike up the lovicr terraces aloiiy:the river are probably due directly to river action, })ein{j; portions of older beds which have be.-n left as terraces by the down-cutting of tlie stream. In many i)la(jes these gravels are found to be auriferous, as is to be e.viteeted, since they are made largtdy of the gold-bearing rocks of the Hirch Creek and Forty mile series, from whicli, under favorable cir- cumstances, the precious tnetal must be concentrated. From these elevated auriferous gravels, as has been suggested, some of the gold found in the younger deposits in the l)ed.s of the present streain.s may be derived; and, sinc<> these gravels are very widespread, they may account in part for th(> occurrence of gold in small qinmtities in nearly all Alaskan streams. Up to the present tiiiu- tlie.se elevated aurif- erous gravels have not been e.Kploited for gold in any considerable ■way, but it is possible that in the future, under favorable conditions, it may become profitable to work them. ' C'ruiav of tlio U. S. reveuiif steamer dirwiii, lX' tliis compaia- tively narrow zoiu' they arc entirely liarrcn. and below it they are very poor. It is probable, therefore, that the gold isderiveij from the basal conglomerate; and from tiie fact thai this euiigloineraie is cinii- posed of fragments of the older aiiriferotis rocks it seems ]nobalile that the gold from these rotdvs has been concei.lraied mccliaiii' ally. In other words, we have he:-e an ancient gra\ei liccj in wiiich gold, derived from the erosion of auriferous rocks, was I'onccntrated. Tliis gravel has li(<'n consolidaled into a hard conglomerate and has been biirie(l for an iTiimense ])eriod of time biMiealh a gr(>at thickness of later deposits. It may therefore be called a fossil ]ilacer, the term "placer" being nnderst 1 to include both ri\er and bea<'h ilei)osits; indeed, in this case it seems probable that, the material may have been a beach deposit. THE KOYtKIK. According to ])rospectors, gold occurs all along the Koyiikiik. The chief producing localil.v is said to have been about .'ioo miles above the mouth, where; the rocks are conglomerates, sandstones, grits, and shales, dipping steeply; tliis is also in accord with the brief note matlo by Lieutenant Allen; and from tlie.se descriptions it aiipears probable that this conglomeratic series is jiart of the Iveiiai series. The gold is sai DISTKICT, AL\SkA. flu* Fortyiiiili- iiii'l ISiivIi ( iv.-k scries, were expo(MJ«l to iifnosplieric (M-osi.in since the l)e;;imiiiit,' «( the <>sili()ii "f the Miswioii Creek series, and jn-ohiihly l.et'ore; and this erosion must have yone on ivt intervals ever since. l)iirinf,'ali tiiis period tin- jinx'esses of -•onren- Iration went on in rivers, on l>eacln's, and in other phice.s, ])rccisel}- a.sat the present (hiy. so tiiat portions ricli in jjoiii, or jilaeers, must (.'ontinually have l)een forming'. At limes of extremely rapid erosi(ni and do|)osition, moreover, such as tlial under whicli tlie Kenai con- ;;h)nieratit' series was deiiosiled, coarse jrravels suital)le for the acen- nuilation of -.'old were rai)iilly laid down. It is reasonable to suppos<', therefore, thai these auriferous conirlomerates or fossil jjlacers will in future Ite found to have a wide dislrlhulion and may become of con- siderable imporlani'e from a commercial slandi)oinl. METALS OTHKR THAN GOLD IN PLACERS. All the i^old produced in Alaska is alloyol with a certain small amount of silver. I'.esidcs this. i)ure native silver is freiiiiently found, alouf; with f;old, in the materials concentrated in the placer workiu<;s, ^'onerally in small rounded or irre^'idar nuggets, although occasion- ally, as at one i)lace in Franklin Gulch, well erystallizeil. Native lead occurs in small nnggcis on llog'cm or Deadwood t'reek. and nuggets of gold which come from this gnlch sometimes contain native lead in small bits. Native copi>er, in small rounded nuggets, has been found .on Little .Mxiiook and Hunter creeks. Platinum has frequently l)cen found in the 'tiikou ilistrict, chiefly in the iliggings in the ujjper ])art of the Yukon drainage system. On Twelvemile bar, which is li' miles below the liig Salmon Uiver, on the Yukon, the yield in platinum is said to lia\c been .' or :! ounces to each 1(1 or 1:.' ounces of gold: 'the metal, liowexcr, was not saved, since the miners were ignorant of its value. m ORIGIN OF PLACER GOLD OF YUKON DISTRICT. The tiny Hakes or coIot's of gold which arc found so widely distrib- uted in the sands and gravels of streams are capable of being carried enormous distances wittiont being destroyed, and are many times deposited and again taken into susi)en.sion by changes of current. Thus it hapi)cns that line or flour gold in small ((uantities may be found along the entiri' cour.se of most of the rivers in Alaska. On account of this indestructibility aid facility of f ransi)orfatioii, fine gold atTords no adequate inde.K of the source from which it is derived. As the gold becomes more abundant and coars(>, however, it is clear that the source is being nearcd. Thus on Kortymile t'reek and on IJircli (.'reek the bars on the main streams were richer than the bars on the Yukon, into which these streams flow. Tn this way pros[)ect- ors find continually i-icher accumulations, until, finally, in certaiu 4 OHICilN OK TlIK IM.ACEK (lOl.D. 367 jrul<-lifs wlinso wat.Ms run iiih. th.. river on whidi ihi- Imrs liav.- \h;-u Iircvidiisly wi.rkcd. ^oM is fouiul wliifh is fairly i-..arsc ami in .-cusi,!. orahk" (|uaiitily. In Iho.si' jiulclics nujtKots an- I'.niiiil, and t'ra;riiii'iits of <|uart/, and jfold mixed. It is ovidcnt llial llicsc pla.-cs ar.' m-an-st tlu' Iriic sourc' of the };old, and tliat from Ikmv liavf 1 n .Icrivcd 11h' liner and rarer particles wliich occur in the liars oi llie lar;:er streams, aud also tlie still liner and rarer particles in tlic rivers into whieli tliese streams eini>ty. Therefore, in im|uirinjr as to the source of ])laccr ,!,'old we may jiass over the widcspnsid line or (lourtjold in the -.'rcat rivers and also the bar di,i:f;in{;s in the tributary sln-ams, and contine our study to the i,'ulcli di,irjrin;:s. l>i:iilVATt(>S- ()|- (,(11,1) KltdM ( KliT.MN 1!( M K l-( il!M A I 1( iNS. nisTuim rioN ok um h (iri.iiiKs with |(|-fi;i(i-..\( k to (M:nic .11 M, -Tlili TI'ltK. The Kirch Creek and the l^'ortymilc (list ricts arc. up to this lime tlic lichest, placer dij,'irinjrs in the ^■ukoll rcirioli, allhoui;li llic new tlij-'uniirs on the Klondike aud Indian rivers promise well. Tlicsc all lie in the rocks of JJirch Creek and the l"(irtyiiiilc series, of the smaller ijulch-mininifdistricts, American (reek and .Mynook ( re(d< are the only ones which have been ]>roductive hen-toforc, and these run tliroiiy;!! the rocks of the Uampart series. All the districts lie in a dctinite /.one or b(dt, which has a northwest and southeast trend and c(irres[)(in(ls with the /one .(ccupicd by the exposures of the oldest rocks alonu; I iic eroded Yukon ,ir(>anlicline. Alo-iir this /one we ma\' say that the richest difjtfin^s haxc )i(>en found in areas occupied by the Mireh Creek series, and also some r'cli uulchcs in the I'ortymile rocks, and that g(dd in payiiij,' (plant it ies has been found at times in jiulches lyin;,' in the rocks of the Maiiipart scries, while iriilchcs which cut other formations have almost iinariably proved barren. If, besides the jruUdi di,Hf,'in,u;s, we take into consideration the richest bar difTfj^iufrs tiUmg the Yukon, Stewart, Hij; Salmon, and other rivers, we see that the alii;nment of the rich jjold district in a northwest and a southeast direct ion, "corresiiondinji' with the belt of the older schistose roeks, is still more strikinj;. The .su,u:,!J:<'stions olTcred as to th(> occurrence of },'ol(l, which are derived from the correspondence al)ove noted, are corroborated by detaile(l sliidv in the u:ulches theiiisclves. (ai.( IIKS IN ltlU( II ( HKKK ROCKS. ^Miller, (ilacier, I'oker, and Davis creeks in lh(> Fortymile district, the entire IJirch Creek district, and also jirobably nujst of the Indian and Klondike ,u:ulches, all have cliaractcis so nearly identical that they may be described together. All these How entirely throuffh the (|uart/.- ite-schists of the Hircli Creek series. These schists cv(>rvwlierc con- tain numerous (piart/ veins, and are cut by occasional dikes, chiefly .'568 CEOLOfJY OF THE YUKON GOLD DISTUICT, ALASKA. T I: 1 1 ' .11 It ' •! i ol ^rniiiitf ur (linrito, which aro womcliinea of liirge size. In all liio >:iilchi-s tiic jjriivclHnn'cntirt'iy iiiadi' iiixpf fragrnontsof vovk identical with that found in placo on Iho ncif;hli<)rin« hillsides. These f;nivol.s vary in thickness np to alioiil 2") feet, frenerally, altliouyh not always, incieasii.i; with the distance from the liead of tlie gulch; in them the schist is in iiiiite lai-ge, flat fragments, often witli ragged outline, and llie (i.tartz is in bowlders of varying size. Tho schi.st fragments all lie Hat : but that wator action has been slight is shown bylhe fact that nii.\erulclies. however, there ar(< slight ditl'er micos, wliich are gemially found t<> be local. Thus, un (ilacii'r. I'oker, and Davis creeks, in tlie Fortymile district, the gravels have a tendency to be liner at the liottom than at the top; and on Ilarri.son and Kaglo creeks, in the Mirch Creek district, there is a ir-ch Cr'cck series, containing veins of (iuartz. This schist is disintegi'ated, ( thf ;rrikvt>I»itr al tlicsiirl'ai'i' 1)1' t lie uiiili'ilxiii^' iiialcrial. < Micii i lu' ;:iuv»'N tlifiiis<>Iri-!t ar.' ciitiicly Iparicii, lull iiMiall.\- llicy ari' u'lild-lx-ariiiu' (»r s«.iii»- ili*. taiH'i' aliciM' I lie hill loin, tin- anion nt of ^'old ln'comiii;r l.s* inuani f!n» toll, iiiilil il ^'idws so fi\i\ tlial llic ;:ra\cls ari' liol worth wa>hin::. 'I'ho portiim wliidi conlaiiis ;;olil in Milllcii'iil qiianiiiy to v>\my wurk- iiiy: under tin; present condi I ions is railed jiay din. 1 1 iiiiisi }h. lN>rnt> in mind, however, tliat the present conditions of wurkiiiir are vrv expensive, and that eeilMin gravels whieii are eoiisidereil worthU-v»at tlio present time would iindoiihteilly, w ilh cheaper inetiiods. j.n.ve profilable. I'lider the present eoiidilioiis liie a\ era^'e thicktierss, ,,f pay 1,'ravels is jierliaiis iiol morelh.in J feet, tiioiiudi rarely ;i>. imn-li as li' feet, wliile the overlyiiii^ ;,na\els a\eraire S uv pi feet and liavt? il niaxiinuin tliickness of alioui l'."i t'eel. itelou a depih of -Jt'i fw-l praclieally no workiiij,'s have 1 ii uiideiiaUeii. alliioni;ii in eertatn parts of tlie country there are mucli deepei' Lrravels wliiidi may in future lie explored and worked. ( iold is foil ml not only in the iriax els alio\ e the siirfai f tin- -M-hisf. but also in Ihi' schist itself, in some cases for J or ;) I'eet il.iw n. aiiws less as the distance from the ^;llrfaee of the schist increases, and as a fj:eiii'ral rule it i.s only that portion of tin.' rock which has been broken up ljy disinte,i,'rati(m and decoiiiposition whiidi is j,'old-beariri;r at all, till' fresh rock beneatli beinjr barren. The depth to which irold is found ill tlie bed-riKdc therefore de[ieiids upon the depih to uhii-h disintejcration has penetrated. On Harrison and Eaglo creeks, where the gravels are underlain l»y clay, ijold occurs chielly at the very top of the clay. Here tlie miiTirt-ts are generally found, and the coarsest gokl. Above the top of ilu- elaythe gravels are gold-bearing for a varying distance up; and U'I>>w the top the clay itself contaius a g''eat deal of gold, which, however. grows finer and less in (luantity as the distance from the top iui-r»Ms»~i. The same occiirrenco of gold is reported in places on Mastmlon (n-t-k. In these places the bed-rock below the clay is practically barren. It follows from what has been said concerning the locus of the con- centratiiui of gold thatthe particle.s of this metal ai' < -i veason «>f their greater specific gravity. The fact that in places the whole thick- ness of gravels is suthcientlj' auriferous to re[tay working shows that the gold can not have accumulated in any special period in the «le|x»- sition of the gravtds; while other localities, in which the pay gravel.* become thinner and thinner and are always at the very bottom of tlie deposit, show various stages in the concentration, until in manyca.-*-* most of the gold is found at the extreme bottom of the gravels, restinir on the underlying material. The fact that the pay streak when thin is usually so ricli as to make it as well worth working as the thicker 18 GEOL, PT 3 liJ: 370 fiKOLOOY OK THE VIKOV (iOI.U KISTKirT. ALASKA. Iiiit iHxitT irravclr*, also points to this coiKciiiiatiii;.' action. Since iK-arly <-vt a .•'liorl .le^tanee Ik'Iow the surface is liarren. It is thnseviilent that tlie<|eeoiii]H»4-il schist ha> acted n Iiatiically to eati'li tlie particles of ;:old .vhidi li.ne wrrkcd down fi tl \ei'lyili^' Lcravcls and which have full nil a jHTnianent safe lod;:inent in the cracks and Joints of the nx-k. and that the schist in this operat ion has |)layed the saini' I«irt a-» tin' clay al>o\e noted, or as would any other material snlli- ••ieutly jM-ni'lralile to arrest the y:old lint not so niiicli so as to perr its Working; 4-ope fi-airmeiits of <|uart/. clinirinir to them. When the pay {travels are washed by water in tin- sluice l»o.\es or other <-ontrivanees the liea\iesl minerals are se])arated from the liirht- est, which are cari-ied away liy the water. In the concentraie left Ixdiind there is a variety of minerals besides jjold. ami these mitiei-als .•.how e^ ifleiit derivation from and dependeiu'e upon the roeks whi<-li eonstitute the larjre fratrments in the firavel. Thus, in the gulches under considenition, the heavier miiu'i-als are almost entirely those found aliundantiy in the liirch Creek schist — ehielly hornlilende. niajrnetiie, and linmnite. When jraiin-tsare found in the schist these are al.so present in the concentrates, ami in about the same relative abundance. Fn ijueiitly <:alena is found, and in m-arly every irnh-h where this is the ease, as, for e.xamiile, on .Miller, (ilaeier, and llog"em t-rei'k.s, veins of iraleiia have been found in the bed-rock. eri'iiii] OKIGIN or TlIK I'l.ACKli (iu|.|) 371 lill.c 1IK> IN hiiUTVMll.K IMi K*. A iilliiilM'r of ;.Mlli'licM wliicli liiivr yiddnl ir..l<| In p.-iyiii;; iniaiilitii's flow entirely tliroii;,'!! Ilie rueks >.f Ihc Fcilymile series. Aiiicm;: these Franklin (inlcli in the Fortyiiiiie (lifiiiei ha> pn.haldy I n the richest, anil may serve as an example I'nr all. 'I'liis is ni-arly a strike fiiileh. llnwinjr alc.iiy:lhe nptnriieil ed^fesof niica-ainl liiirnldeiiile- sehifsts interbedded with niarhie. 'I'hese schists are iiil by l'rei|uenl, dikes. At the extreme head ot' the i;nlcli, I'Inse to liie divide, is a jrreat dike or intrusive mass of j;raiiile or iria liorite. 'I'h,. u'ravids in the creek bottom are composed of tin- same iii/ttcri.ils as the walls of the valley, and contain besides these materials freipuMit tniLrmciiis, often rouniled and of lar;:e size, of oli vine-basalt, a i k which ll,•l^^ not been found in place here, allliouch it occurs abundantly Just to the south, in the country drained by Chicken (reek, (iold has be(>ii found the whole lenirlh of the ci. „ ,is far as prospected, and occurs in the very bottom of the u'favels oi' In the irrcy:ularit ies of I he under- lyinjr )>ed-roek. The thickness of pay ,i;ravels varies up to aboiii i' I'eet, and above this, as in other jiuh-hes described, lie barren ^i avcls. which, liowever, do not dilTcr in f,'eneral ai)pear,iiice from those which contain ;roled-rocks are of diabase, til lis. imi>u re shales, and (piart/.itcs, and in the bottom of the .'{ulclies tliesc ro(dle tliat these also liave cont rilnitecl soniewlial. On tile upper pari of American (I'ci'k wliere jrold occurs the rocks wore, so far as examined, massive serpentine- and cidorito-t nil's, impure lirie-irrai.'ied (piartzil.-. and sandy limi-sloncs. At the only claim .vl'icli was Ipein;,^ uni'l^ed t lie ;;ra\t'ls in the Itottoni of the ,i,'idcli wore exceedinj^iy liariiiw, often not more than liiorl"i fed wide. 'I'he delrilal aceimuilalion at Ihisiilacc is only about :} or \ feel thick, and is entirely made up of anj^ular fraLcments of the rocks which overhang the St ream jirecipilously, ami of the <|uartz veins which these rocks often contain. This fiati'iiieiital deposit is nearly liarrcn. all the ;,'o;d bein^' found on tup (jf the lpe(l-r ftppaieiilly yielded the jrold, wliicli has been collcctctl alonj; schis- tose /oi:e- (if ilie umicrlv inj,' r.iek, aiicl these i,'ra\cls seem to have a inirely loi'al source. Associated with the ;rold, in the \cry bottom of the {Travels, are freiiueiit rounded or .suiiaiiirular pebbles of ina;r- netite and oarile, wliicli scom to be derive(l from the veins which fol- low the shear voiics in the neiiihboriiiir rocks. I m S(MH( K dl' rill-. IiKTIMTAI. At ( f M 1 I.A 1 li >NS IN <.l|.( IIKS. It has beiled tutrelher with little assert meiit. The male/ials are ;:eneral!ythe same from top to bottom. As a rule, the frai;meiits eoiisist almost entirely of rocks identical with those ii; the walls of the ;:ulch. and often slic^v chaii}re.s in dilTerent parts of the {^ravels eorrespondin^ to chaiure:, in the wjill rocks. Apart from this evident relation, it is clear that those larf,' ', Ilat fraj,nneiils of frajrili- schist can not li,i\e been carried far froi their original source; and (he same is true of the large bowlders of (|uart7. and associated rocks. Any great amount of water ai-tion, moreover, such as would be necessary for liaiisjiuitatioii, would Luvu w •^ 8Pt Rli ORIGIN OF TIIK I'l.ACr.l! liOI.U. roimdod and assort o< I ili,- t'latiiiu'iils. 'I'li.Ti'lur.- tli.> man-rial is.'ss.Mi- tiallya talus \vliic]i li,,s Ih-cu sliuditly arraii^'i-d ;lii.u-Ii iidt ;.'rt'atlv niiMlificd. .Morcovor, those iiortioiis of the jrravcls wltiili ar.- most liitrhlv auriferous sometimes hear a relation tocertain parts. if th.- asMH-iateil bed rock. For example, on Fraiikliu (Juli-Ii ,->oarse ;:ol.l is found .nhundantly just helow a w iile (piaii/. vein in tin- tied of the «uleli, while ahove the vein the irold isliuerand scarcer un n,i;.'"eiii Creek, in the gravels which overlie tin- broad jrranite dike, the ;:..ld i-. tine and comparatively scarce, hut coarse ^rold is found intlieschi>i imme- diately above the f,'ranito contact and from there enuiiuM.iuslv upstream. It is possible, however, that in this cjim- the ^'leater conc'i iitration of the j;old on top of "the schist as e cumrlom- erate, derived chietly from the old .^'old-bearin,' ro.-ks, while the frravels which lio in the rest of the creek are ])raeti<-ally barren. Cross sections of the jrulclies have nearly ;d ways a ^.'eni-ral V-shajie. The smallest streams run in veritable iiolches, while the laru'er ones widen their liood-plain s(( that Hie bottom of the V Iwi-onies broadened .indllattene<1. From the sleep walls of tlie^ridches fra;:mentslo<.-iened h\ frost are continually slidiiiir down by foi-ce of ;rra\ it v or are uru'ed down by freshets or heavy >nows. ^■( i-y fre((iiently a c-i,n-iderable accumulatiou of these fi'ajrnienis comi's clonii sucldenly in the form of landslides. At the bottom of liie u'uicl, tin- ileirini- i-- >mootliei| and sliirhtly arranged by the waters. It is sometimessupixised by minersthat the L,'i-avels may Ite due to a jrencral j:lai'ial action, which has bi-ou;,'hl i he auriferous material fiom some unknown distant souri'c. It i-. ho\\r\i-r. (piiie elear that y:laeial action has been [(rail ically absent in the lii>iiir\ of the eonniry. Not only was there no general ice .sheet <'o\i'i-im: hill and \ alley, but e\en local glaciers, lillinii; t!ie \alleys while lea\inLr ihe ridue-. free, were absent That this is triie is shown by the total laekof all iilacial phe- nomena and by the ])reseni f pinnacles of roek whieh have bii'U left by dilVerentiai erosion ami which nould invariably ha\e l)een broken diwn by a glacier. Kxam|)les of ids are the l>earnlelies which have an almndaid supply of snow, the hea ice- is eiitirelv melted. The saiiiecrosivi' action sometimes tends to widen the valley by more rai)id wearinj: away of the side slopes. Where this viiroroiis erosion talK MKt llAM. Al. •N' FNTI!AT1"N. My previous .^.-i-ri iliiit iln- \sii\i\ -ilil.. iiiili'^s the iTl'avels \vefi> t'fe(|iientl\ s!i'_'iit!y iimveil or iJiM iirlwil, m> a> tci permit iniiveilielll ailliillU' 'lie [lai't iele-.. It i> iliiiliiiiliteilly true that a la lire l)ai'1. (if »lie lii-aina^'e water |H-ri-i>late> tlir( the ;,'ra\el> wliicl. lakes plaee in this letrion in the warmer pail of thi' year. \\ hen the ;, ravels are tiiawed l>y day and frozen liyniiiht. must al-u prinluee, hy all e mate expansicui ami eontrai-lion. mn<-li iiio\iMiii-nt which would I'aeililate the downward pas^ai:"- of the u"'ld |iariieles. Wlieii condi- lions are so favoraltle that nior>t of ilie jiold thus works Ik was to the bottom ot the irravels. its retention :in<] <-oneeiiiration dc|ieiids con- sidcrahly upon the ehai'aeter of the ln- of the creek lioiiom were almost entirely barren, since the rock otTered no irreirulariiieN to arrest tie _'ild par- ticles. The ed'eet of schists and other nx-ks of nneipial hardness in the eoiieenlration of <;o!d ma.v Im- eom|iarei!i 1 with the current, althiiii;;h often at lri<'t> ••vcii tin- iii|;;cs diviclin;,' tlio jj;iilclics Iiavi- I n ^"^ iTiHlf'< feel or iiion^. In tlie sti'cani \alleys there is lh(> same strin'tiire, only the t<-<'th are smaller and more iiumei'oiis; thus nil l'"lieltere feel deep, I'siialiy. Iiowexcr. it is much wider th.i'- det-p, and oftiMi the gravels in the whole bottom of the yiildi pay f<'i wi.irkin|j:. Since the OKinix OF THE ri.ACKK r.or.D. ,'577 und«'r,rr«juncl water, wliich soems to In- larizdy iiisi num-iital in liiiiii:- ing alKiut tlie (•uiulaiil in tin' Ijoltoni of th<' Iwil-rook valley beneath llie irravels, it is liei'e that the rich«.-st i»ay streak slioulil be expeeled. 'riiereldic, when the stream is fviil«-ntly uii^rratiiij: lalei-ally and is eoutinnaily eiittiuLr into the limits of its old valley on one side and leavinir behind it an old flooi»c<-Mally those of the alkalies.' Many of these salts are found almost universally in snrfaci^ waters, having Imm-ii derived from the 8«-«-n shown that organi<' matter alone is sulliciirit.' That these facts which have been obser\ed in the labor-atorv are imiiorlant in eonsideiiny; the ordinary i)i'ocesses of nature is proved liv many well-authenticated observations, in drifts through aurifer- ous gravels jiyrite often forms, and this pyrile almost invariably con- tains metallic ;:old.'' In p.ieces of wood found in thi' Australian jfTiivels pyrite has been deposited, sometimes entiri'ly rcplaeing the orgsinie s'rueture, anAm. ti^-iiii-t. V..1 HI. !■ -MS. ' H. A. Til iij]~.ii iJ.ilil Fi.hl'* aii'l Miin'i-iii Di^irl'i^ ■■f Vi.fi-iii. Mi>ll»mrnf, Isiiii, p. -.i;-. • U«1UT Luul-. Milfnil. Matf-. Nmv , 1M':|. p, Jit. K v.m Knuil/: -Viii, iMnjluiti-t. Auk' . I"'."!. p i-e ■•t-*! neM» »n'i Minvnil I'l-tri.-t-, ..f Vic-i..i-«i. ]>.-K, T. Kgii-ntmi: Truiis. Aui. hi»l .Mm. Eivf - V.i IX. Ji, tlfi •G-W Firkl.amlMluiTal Uistri'-I« .if Vi.t..iiii. p :.'lii. '<'»}». ot . pj. 'S**.y>\. •Tran» Am. liiKt Mm F.iii.'-^ . Vol IX, ji il4.V • Ant . p. lit- :' T. A Ri'-kani. (.Vrtain lUmiimilur i)i'imiiti.'1i<-v3 uf i.'.ilil-lH':iriiiK 'l"i"''2- Pri«-. ('ulnnulo Sci. .'578 CiEOLOfiV OF THE YfKON GOLD DISTRICT, ALASKA. m Ml i; hov.omo eHpocially ricli in tlioso layers m- beds wliicli oontiiiii iiuich orpiiiic iiiatlcr. In placer (•(iiiiitries jtlates of irold are sometimes foiiiid ill the trrass roots, heintj probalily prveipiialed tlieic by tiic or;;anic iiiateriai.' It is iiiipossii)le todoiiht. therefore, that solution anil redeposition of .u'oid take place eontinnally In nalure under the inlluenee of onli- nary draina;rc' waters; and in auriferous {.'I'avels. wliieh are porous and thus opon t<( the circulation of watiM', jiroeesses of this nature must ii<) on continually. Indeed, proofs of this are not wantintr. Aniouir the most con\ incinjr of these is a si)ecimen shown the writer by Mr. II. W. Tui-ner. of the (;eolo;,'ical Sui'vey. This s|)eeMiien ci'U- sisted of placer }rold and black sand from the auriferous ffravels of Providence IIIIl, I'luiiias t'ouiity. California, the black sand consist- ing; mainly of ma^rneiite. with some hematite an to accomplish tlie transference of any jrieat amount of iridd as com])ared with the time re(piired for such ti'ansfer- eiiee by the active processes of nieclianical abrasion and concentra- tion. The actual value of chemical inlluenee, of cour.se, will vary In difTi'fenl count r'ies, belnv' doi)endent upon the nature of the percolat- injt waters, the iiresence of materials capable of brln^inj; about a jire- clpitatlon of irold hehl in solution by such waters, and the lenjrth of time durinj^ which those proces-ses havi' had o[)portunity to ,i;o on. It is, however, probable that, as a rule, mechanical ellocts have been vastly more important.'' It has been asserted by some writei's that the larj^e nujjuets some- times found in jrra\<'ls can not be derived from veins. In Califor- nia, iiccord I njr to J. I). \Vhitney,' the larfrest nuj^iret found weijrhcd about -•") pounds, but I'l-ofessor Wliitin-y points out that hirfje uua- ttets were rare in thes*- ^'rjivels, and that larire masses of j;old were found in some of the i|uarl/ veins. In Australia the lai'jiest nuf;y:et found (the "Welcome" nuj,';ret) weijxlied over 1^4 pounds. From a ([uai't/, vi'in in New South Wales a block of ;,'old encased in <|uartz ' Trans. Am. Inst. Min. Eng., Vol. IX, p. Ui. • F. l'iA..i)n\', Oi^nesix i>f on- ili'|K«it«: Trans. Am. lu.ft. Mln. Ens . IWfl. \>. Vil • AurifLTous Wmvi'Ls ot tlii' Sierra Xovudu. \i. .W. I fi'tnii.] ORIiilX OK THK ri.ACKI! Gdl.D. »i "* t\ was takon from tlic sml'acc fiunipin;! ni' a vein whicli \v.'i^l,f.l 7.". pounds, (Hit of wliicli iin pounds Well- iiuic Lfuld; t'mni aiinlliiT i|uai't/, vein a mass of ;;old \vci!.'liin,i; ovor 4o puuiids was taken, and with it, other smaller jiieces, weiifliinjr in tlie aLri:i'»"-iile ovi'r :!:! i>ounds more. Ill till' I'ral .Mountains a famous nuir^'el was found at Miask. wliieli was free from quart/, and weiirlied over S7 jioinpls.' It will thus tie seen tlial masses of u'ol'l in quartz veins have approached \eiy nearlv tlie si/e of llie hiriresl nuir^'els. .md tli. in .\uslra!ia sueli masses have heeii found weiirliin;,' several time is much as the l,ii;:es.| nug- gets in tlie (alifornian j;iavels. It is evident, thefefiiii'. thai it is nut necessary to appeal to chemieal ael ion in the gravels tciaiiuiini I'm- the forimition of nu^TLrets. In the Alaskan irravels a stud\ of the nature of the ^fold shows that ehemieal processes have had very little to do willi its eoneent ratio:'. 'l"he metal oceuis in irreLTulai'. Hal scales, like those which are founil tillinir the erai'ks in thi' quart/, veins, and a tuammillary form, su^'^cstinu' deposiiidu from sdliilion, has not been notetl. 'I'he Hat forms are best seen in ihi' smalli'st. grains, the larger nuisses having been generally snincwh.ii loundi'd by eontael with liarder bodies. .Moreover, the gohl. fnim the smallest to the largest fragments, is often mixed with vein quart/, in all ]iiiipiii- tions, in such a maniu'r as to leave no doubt as to the det lital origin of both. \o large nuirgels have 1 ii found in the .Maskaii gravels. the largest being the (Uie found on I'lauklin (Julch, which vveighe. Xto. I r i) \ CirAPTK R VTT. COAIj IX TIIK XKIOIIIJOIMIOOW W TIIK GOT.T) HF,Tyr. OCCURRENCES. Tlio thick bods of tho Konai sorios are characforizod pvorywhcn:' by nbuiidant plant ii'inains and by more or less eoaly layers, ami lliere frcqueiitly ocieiir seams .)f pure eoal. Tho underlying :>[ission Creek series is also highly earbonaeeoiis in some parts, and also inelndes beds of coal, but, so far as ol)served, these beds were impure and slaty. On Lowoa River, a few miles above Rink Rapids, thcrv^ is on the right-hand side a blulf where several .seams of eoal are expose(i. The htwest is about :i feel tliiek, of wliieh probably about IS or I'l) Inches is elear coal. Thi.s eoal is rather slaty and lignltie, and probably eon- tains much ash." The seam is underhiin l)yu gritor feldspathie sand- stone carrying plant remains. I'nder the niicrosco[)e the fragments of this rock are seen to eou-sist ])artly of (piartz and jdagioclase, but ehielly of a mierofelsitic material which carries many small needles of plagioela.se, and is evidently, the groundmass of some andcsitie lava. 'rh(> cement is generally a cryptocrystalline paste, although in parts it ccmsisis largely of calcile. Above the coal seam come (; feet of clay, with sandstone and grit layers, and over this lie about 10 inches of coal like that mentioned above, but probably more argilla- ceous. Xe.xtcomc t feet of lava, having line amygdules at the bottom which grow ])rogressively coarser toward the top; it is thei'eforo a surface flow. Tho rock is light-brown, with light feldsjiar plieiio- crysts, aiui under tho jnicroscope soonis to bo probably an andesite. 'J"he phenocrysts are a clear and glassy phigioclase, altering along cracks to calcito. The gnuindnmss is holocrystalline, with a llow- structuro, and consists abnost wholly of small, hith-shaped plagioclaso crystals. Over this lava como about 18 inches of coal as before, and then clay, sandstone, grit, .shale, etc. A tunnel has been run on the principal coal .seam for a short distance." Coal Creek runs into the Yukon from the east side about 8 or 10 miles north of Fortymile Crook. The writer has boon informed by J[r. W. Ogilvio, of the Canadian Survey, that about 12 miles or more up this crook there aro two 4-foot .seams of coal, separated by a bod of clay containing leaf impressions; the country rock is sandstone. ' O. M. Dawson : Ann. Kept. Ouol. Nat Hiat. Survey Canada, Vol. Ill, pt. 1, p. HHB. 3S0 w PlTKIt.] f.'OAI, IN Till" NKIi;ill!i)HIH)OI). ;5si SiK'cinuMis of tills ciial wiiicli witc .sccii liail a ln'iillaiil lii^liT. m ili (■onclioidal rractiiri', ami wcrcDl' not iccalil.N liu'li' wcii;lil, 'I'lu-y I'cm- taiiifil tiny specks of jiyrili' and grains ul' aniliiT nr aiiilH'i--lik<' ri'sin. Tliis coal is said to Inirri w illi at)oul '< per ccnl of asli. t »n llic small creek a lew miles hduw Coal Creek, on Ilie same side of the Yukon, coal of llie same iinalilx oi'cnrs. ( >n American Ci-cek, and on Napoleon ( reek near llie head of T'orty- inilc Creek, iniinin al seams were fo\ind in I lie Mission Creek seiics, bnt no \i(»»\ coal. All tin- localities w liicli lia\ e been mentioned aliove aie In ( anailian territory, yet are in a rej;ion so situated jreoijrapliically llial il-de\el- o])nient anil tlial Yukon, Just below the niouih of \Vliyniper River — or Hess Creek — there are exjjosed free!>.v for exjwrtation. It is |)(issilile, however, that in some of the older rocks coal of bet- tor ipiality m:iy be found. Dr. Dall^ notes that at Cape Ueauforl coal of a \ery ditVcreiil ipiality from the lignites of the southern part of -\laska was found, in probably Carboniferous strata. Fossils col- lected on the Yukon in the nei}rhl)orliood of the gohl belt show that Carboniferous rocksare present in this rei;ion, but, so faras obser\ ed, thev here contain no coal. ' Bull. IJ. S. Gfol. Survey Xo. 84, Correlation Papers, Xeoveue, p. 237. »Oi). cit., p -'41t. Wr ClIAl'TKl! VIII. ST'MMAItV AM> IMtACTK Al. A ri'MCAIH »NS. siMMAKV III- i;i;i'iii;t. 'I'hf iidtcs wliicli liiivc l)ccii inan gold ))('lt iiKlicatc thai tlie i^colujiical ciilimiii in this if^'iini l>«-;:iii- witli a fuiKlaiiKMital granite, wliicli is uvcriaiii by liiick i[iiart2itt->: anil that tliis iniarl/ili' si'rics is nvci-iaiii liy inliTln'(|(lcil s..ilitiifiitar>- rocks wliicli \vcr<; oiij;inally samlstoiu's, liiiifsloiics, ami >iiaU's. All these rocks have Itcen siil).jccli'il to ri'j;ioiial prossurf, ami all \ut\v b(!Oii rcinlcri'il schistose toiicthcr. Tlic ctTccts ot" the >!icaritiir. h'>w- ovor, arc much more niai'kcil in the seilinientaiy locks than in tht- inoi'(> massive ^'I'anilc. A\ aliotil the same time as the ilcvflopiiu-ni of schistosity, probahly near the be^iiniiini; of this pinccss. .lik-"* u«?r»» intruded into (ho sedimentary rocks ami iniail/ veins w.-rc t'>>riiii-iil.— •- (|Ueiit rejriiinal movements, were frraniticor dioritic, while later dik«->. as a I'lile, were more basic and moi'e acid, and the linal in.jc-rions. *«• far as observed, were of extremely acid dikes associated with •|iuir1z veins. Previous to the intrusion of these xcry latest dike>. but at a licriod when the development of schisli)sit> was nearly at an •-ml. theio occnrred vast oiit[)oiirinj;s of basaltic and diaba>ic lava ovi-r larj;e areas, and these if^neons rocks, with lull's and impure >;»nd>tr>ni^ hifijely derived fi i them, consliliite a vei'y thick scries. This •■••!- canic activity seems lo have been very nearly the end of the i>«Ti«>"l of disturbance which had been inaiiifesled by the shearinir. foldin^r. and in.ieclioiis of i^nieoiis material. Sultseinicnl to the ontiH.iiriii-.: •>( the lavas, however, dikes were still intruded, as is provtil by ilif occurrence of these bodies ciiltinu the cIViisiNe rocks. l!ut tl»-s4> dikes seem lo ^' loii;; chielly to the extreme types which chaiact.-ri/«- the close of the .-eries of intrusions. The i|uart/. veins which occur in the district seem to U- t-lux-ly connected with the dikes, and were probably formed at siiot-sstie periods. correspoiidinir with the repeated iii.jcclions of iiineoiis iiiat«- rial. Therefore the oldest veins have been sheared toirdher with the ohlest dikes and the inelosinjr rocks, and have been fault*-.! aud 3K4 r.Kol.MCV or TIIK VIKON OOI.U msTRICT, ALASKA. »lr»-I<-h<-«l »> that llicyan- aiii<-t granitic an-l aplilic intrusions, aii'. liki- tlii>f dikes, iin«li«-ar«-l iiraeiicaliy nnliiiiileij. ami tlii-rcrorf may he in jiljices «i.i>ient. All tlie>e veins seem lo eai'i'y ;,'olil in v;tr>in;; Mlliolints, Jlllil llieV proliallly are llie ellieC soliree of the JTolil now Ih-Iiii.' taken from plainer ili;.'i:in^'s, Followiii;; the ]M-rioil of ),rreat la\a ••niplions, litjiestones ami other s«-al>ly from I >evoniali to Crela us. Altove tlieso ^«^•^liIllellts »a> laid down a very thiek serii's of fresh-water Ix-ds, wLk-h an- largely confrlorucrates. coiitaininf: abundant plant remains fciiid seams of li;:nitic eoal. This sei-ies, on the eviilenee of its flora, ha> iMM-n referred to the Koeene. Siihsecpient to the formation of this ceries, violent movements took jilai-e in the earth's «TUM. tir»-at folds were formed, amonu them thai wliieh has lieen iiaiiieii tin- ••Yukon jjeaiitieline," which lias a northwest and south- «-a."'l in-iid. The Ix-ds were upturned, I'.nd the developmi'iit of the Alaska of tlie present day liej;an. I '.y erosion of the Yukon .ireanti- clinf thi- difTerent formations were c.xposeil in northwest aiul soutli- eaM trcMidinir zones. 'I'his is i-spi-eially llie ea.se in tin' lowor schistose };oM-lM-arin:r formations. I'arallt.d with tho a.\is of the fjeantieline the chief Iilojrieal times, however, the land has l)een suh.jeet<'d lo repeate«• uik' «i|' llic cITi'cts of iiiiiriiic Hclioii ill llils period; oilier llijiii llii>. lio\\e\er, no iiiarliie ile|)o>ils lllive lieeli round, iilld 1 lie siibniefgence iiiilsl liii\elieeii briel. ills prolialile that llie niaxiiiiuin Mitinier^rence may lia\e lieeii more or less closely eonleniporaneous with the maximum evieiisioii ol' the irreat cordllleraii ^'iK'h'r, and this may ex|)iaiii the alisence of ulaeiatioii and also of ilo-ayed ;iek over so laru'e a portion of AhiNka. The eor- (lilleraii ({lacier soon retreated, howexer. ami ihe laml al-o Ixiraii to rise. On the retVeal of the sea. the eoiinlry lieiiiir si ill low , the valleys of tilt," old si reams were ill part occupied hy numerous lakes, ihi' water HC'i'limillatilif; ill coiiseiilleiice of the slii^'yisli draina;;e. or ha^in-. were formed l»y local de[)rcssion or irre;;iilarit ies of tdevalioii. In ilioo lakcH mud or silt rapidly acciimiilaled. Willi inere.isin;: elevation some of the lakes became drained and others were rediieecl in e\ieiit. The slreains became more rapid, and the \alleys bi'^riin to be exca- vated a^'aiii. This is the condition of lliiii;;s at present, and it is probable that the elevation is still jroiiii: on in a general way. Auriferous (|iiartz veins were formed in the ojijcr rocks at dill'ercnl intervals, and tlieir formation was accomitanicd. in a j;ciieral wa.\, by tlic devclo[)inent of schislosity, so lliat the veins may bedivideil into an older sheared and ayoiinjjcr iinsheared .set. These \cinsarc found chiefly ill the lii},dily schisto.sc sedimentaries whii^li have been called the iiircli Creek and the Kortyinile series. They are occasionally found in tlie fuiKlainental finuiito, and tlic yoiintier .set is sometimes found in the i<;tieousand ])yrocIastic rocksof the |{aiiiparl scries. In many places it has been noticed that the yoiin;rcr set of ipiart/. veins, which, on account, of their unaltered condition, can be iiiori' easily studied than fhe older set, grade into acid dike rocks, such as aplitc. From this and other considerations, a theory of the formation of thu auriferous veins has been forinulaled, namely, that they re|)rcseiit, the linal stage of a gradual process of rock consolidation, the rocks representing the other stages being found in the same districts. 'I'lie gold is supposed to bo a nearly universal const it iieni of rocks, and to lia\'e been a ])artr of the general magma; ami its abiindaiice in some I'lniiiiin l'"!'1 .iihI .sil\ (T aliiML wilh iillicf iiiitals. 'I'lii- iiii-l>> 111' III)' Karii|iarl m lir,-. have hi'i'ii i'\|mi^"mI t>> aiiii<>-i|i|i<'Vic crusinii >iiicf till' I iiiic 111' ilic riirnni inn 111' tin- .Mi^^illll <'r<'vk sciics, .-'III! pnilialily lii'l'iirc. a>- sIkiwm liy i-iiiii.'liiini'i'aIcN. 'I"hi> MTii-h, liiiw- fvt'i'. ami I III' iiMi'i' i'iirU> wcri' lirst i'\!icim"I Id arlivi- iTiisimi siiIim*- i|iii'iii In 111!' iMisi-Ki'iiai ii'\ iiliiiiiiii. .\i 1 lii?» |iiTiiiil 1 III- wcariiiir away III" till' ^ iikmi ;;«•»;. lii'liiif rxposcd liivnlil rocks in a ^H'litTai limail Ik'M, wliii-li cxii'mls in a mirili\M-sl ami sinilliwist 'dii linn I'ur at least a lliiiiisaml niili-s. SiiliMMiiicnt crosiiin lias ii|MM'at<-i| unly ti> liiiiaili'li tills /mil', vvliich al picseiil i-inslilnti-s ilii-^olii licit ><( l' .■ \'iikiin ilisti'ici III' Alaska ami llri sli ('iii',::it>ia. Kvcv since ilie liei:iiiniiiLr <>l" llie pcrind nf active irnsiiiii '.lie ^'iiiil-liearintr ijiiaitz \cliis ami iillier metallic acciiiiiiilaliniis lia\e beeii I'nkeii up ami c ir- I'leij away liy watei's with nilier im-k dftriliis. lunl from tliis lieicio- :,'eiieuii> mass the Hold, lieiim lieiivicsl, has always l:ad a lemloiicy to cuni'eiit rate incclianicallv al llie hiittom ul' any deposit. 'I'liiis at the picseiit day it N t'oniid In tin- I'olloiiis of the j^iiiches and on the hats of ri\ers. Tlie olilcr acciiiiiiilatioiis of detritus also ciuiiain coiiceii- tialed ;rolil. ami these |iriilialily riirriish some sU|i;ilies to the luore it'ceut acciiiiiiilat ions. I'UM ri( .\:. AI'IM.Il ATlo.NS OK ( ilCOI.i io!( .\ I. I'ISUVI IIM.ES. 'i'lie i;oli| 111' the \'iikini district is < liiclly derived Iroiii nwn'.z veins whitdi arc I'oiind iiuisl aliiiniianlly in t lie schists of t hi' l''oi'tymile and the jiireli ('reek series, alllmu^di not iiirreijueiitly in t Ik ii:iieiiii> and pyroclastlc rocks of the |{aiii|iarl sories. It is also derived, althouuli to .'t far less ( \."'it, from i-'ipretrnated shear zones, which occur cspcciallv III the Katiii)ai't .scries. Of the ijuart/, veins om >et is sheared ;; ! one iiiishcared. 'I'lie lirst is 4lilVK:iill to follow . i.ir the veins arc liinkell ami liolipersistclit. The \ ciiis of the secoii •set ar<' often persistent ami wide, and in .some cases may lie mined p 'iiitaliiy. 1 mpieyiral.ioiis alonir slic-ir .-.oiics aiay a'sii In Mime cases lie siillieieiitly rich In illelallie iiiliici;ils lo I'orm ores under favoralilc ciiiditioiis; and the rock in the rei;ioii of these shear zones is oft"ii iinlaiilted, so t liat I lievi- (lie liiidies may lie expected to Ik' <'owipavai i ve'y persistent. 'I'lie i|ii.irl;'. veins at !• reeled with i!i!::'^, chiefly- I i;;li: -colored cr\ N!;;lllnc rocks, Mich as granite an ' .iplitc This should 1m' kept in mind in ;irospectin^. and aurli'eroii.-^ \ciiis nuiy lie luoked for in the schi--ts near .lie '''kes. In some ca.scs, a'tlioiii.di not so comiiiouly, I lic\ iii.'iy also lice 111' at some oislaiicc from a dike Thcsi icold liearinii' rocks form ,i detiniic hell, extemlliic tti a p-noral way from the !,oN\er {{amp.nls of the ^■|lk!lll and liclow in |)easc Lake and oilier iiiiniiii: dist rid s In liritish ( oliimliia. .• distance In a straiu'ht line nf aiioiii a ilioiisand iiiiies. of this disiaiicc. Iiio nr .'i hut i1m- li.l,. ..i i.1;i,-.-i> iir.- Imih,.!. Tlii> i> iialiirally llic .ms.. since ih.- u''>l n,.,. in Iliis licit, an.l also the must paying' l.ar ^'ravels. ,iltli..ii(;|i jm.- -..I«l in some cases may 1 arrieil snmcv. hat iiiilsiii«. ,,| )l„. 1h.|i. ami rnav lie siil1i('ieiitl>- <-ciiicciitiatcil in l'a\ maiilc sitiia! ii.ns to |iay I'-.r wasliinir. Till' Hirch ( leek. thf l'oii\ mile, and the K ioudikt- (listriCH are all in this hclt. ami are all in the schistose rucks, an.l in \U,-^.- r,„.k^ new uiim> plac.r .li!.').'iii-s ,,f vuIum nia.v alsu lie found in tln' rocks o| ih.' Itampart series. I.ul as a riil« hijrher horizons at.' |.iiihal)ly liarreii. saM- in e\c.-pii,.nal cas.-s < ..n- jrloin.' rales maili' iipul' the dftrittis rr-..m ilie schistose Uiich ( r.-ekand Furtymili' roi-ks sliuulil in- ])ruspecteil. ho\M'\.-r. since the\ iiia\ prove to lie l'(.ssil plai-ers. .ViHMcnl irraM-ls l\iiit: aUiv.^ ,he pr.-seni -.tL-aiii <'h;»iinels sho.ild also lie kept in iniiirl, i'urthe.\ iiia> in plac- cuniaiu siiHicii'iit ;,'uli| to lie prulilalily iiiin.'d. The ([.lesliuii as to wh.'lhera .■ertain di'posit. .'ither pla.-.-i ..i Iw-d- ioek, contains cnoiiirli i;(.ld or metals to n-niler ii proliintil.- tor work- ing: is one which can 111' solved liy no universal rule. Aile|M.sit whicli under crlain circuii'slalices is < vtrem.'ly valiiahh- may umi.'i ..tliei-s he etitin-ly Worthless. Tile circumstances w hi. -h miisl Iw lak'-n into euiisi.leraiiun are: Cost of mitiiii;:, ease of separatiit<.' iln> m.Mals lidiii th.MMi's. faeilityaii.l cost of i ra;ispuitatioii. ami niiint'roii.soth.-rs. The i|iiesiion as to wh.'ther any ilep.isit ur an.\ in in my: district in ;.'i'ii- eral will ll III.' prolilalile .-an lie only partly suIm' '. liv iieulu;;v. fur the l-cst .Icpemis ll[iuli other scienci-s. .1 the pri-si-nt . i'lie ( Is'."'.) lalior in Alaska is worth «1 an I r, ofiKi a da.\ , and this irjves a fair hlea of the a verairi ""I of pi-oiliiet iuii of placer irolil, which is two or three times that in more ac.'issihle countries. In this rei.'iuii. ih.-refure. a ]ilacer di'posit in onler to repa.v workiiifr iiiiisl at pies.-ni I..- ilii..' ur four times as pruliiahlc as a deposit in must other places. |n iH-d-roi-k mines the c.\ pen s.'s would he prop.irti.mat.dy iiiiich ^r.'a'er. sin.-.- mure e\)iclisi\(' i'iiui|)meiits. iiiacliiiiciy. .-tc.. iiiiisl lie pnn i.led fm the piu- .li'ctioii. an.l pr.ilialily facililii's for t ranspoitat ion of iln' ur.' fur lony ilistances. ruder exist in;,' c.iii.litiuns. iherei. r<-. lli.' pi. ilialiilitv uf lie.l-fuik iiiin.'s siillii'ii'iit ly I 'I'h to iepa\ work iiu' is no! i;r.'at. Were these coiiiliti'itis y^rcatly iinpr d. however. p,i\ iiiy mines in the Im-i1- i.i.'k iiiiyht lie foiitnl, ami .'oul.l hi- wuike.l in spiti. uf tli.- s.-vere .-li- tiiatic .'onditioiis. The^iro foiiiilry itself pniduccw hfirtlly cnonfjli food to support life, all pr(«\ isioii> arc now brousrlit from San Kranciseo or Scaftlf, tli>' usual rouh- licinj: hy sea to llic mouth of tlio Yukon, ami tlicncc up tlio river to the iriiiiin;,' ilistrict, a ilistanee of over l.ooii niiifs. This nuikcs supplies so c.vpcn.sivc that unless l)elter- transportation is pm- vicleil tl ountry will prolialily lie aliaiuloniil as soon as the rii-hest plaeer WDikinu's have oeen exhausted. l'"iii' opi-niu},' up more rapiil 4'iiiiimunieation, some route from the <'oiisl in llie \ieinity of .luneau seems most feasilile 'I'he waters of the^ukonare na\ivMlile for river steamers of li;,'ht draft up to the head of Lake Umleman, exeept for twoortliree jilaees where short rapids exist. Two or three steamers built withdu nsideration as to the ehaiaeter of that part of the river on whieh they were to ply wouhl I'orm a complete eonneet ion helweeu the head of Lake IJnde- man ami tliei,'oJd reirion dui'iuf,' the lo;irorlive months that the river i> util' I'll/en. 'I'he head of Lake Mnilenmii is only about -j'l miles from the lutvi^able watei' of the sea. Another measuie whieh wiiuhl 1m' of ,u;reat value would be the building of a waj,'on road from the eoast in the vicinity of .luneau to the .junction of the Lewes and the I'elly rivers, whi<'li point is below all obstructions to navifratioii. This road should be built a<'ross some of the mountain passes other than iheChilkoot. whieh is nnw used, for the Chilkoot, aIlliou)j;h short, is hij;lier than its neighbors. f < I! A I'T K H IX. MK'III«H» Of MINING. ii.vi: li|>.i>lXfiS. In baiMlisrsin^s fho inatorial wliidi da-, to \>f \va«l)olilcri: ami l»y whait-vcr pnK-i'>> ilii-i:(il(| i-.i'\i laiMfil, these ](ehl)les ar-e separatfil fip^t: tlii-r<- tlit-ii rciiiains tin- liiiei- male- rial, wliicli is iiiaije up iif tin- hi-avier •••.ii>iitiieni>. nf the same iipek^. I5laek saiul, wliicli ei>iisist» <>f iiiairtH-til*-. hematile. ami sdinctimes (rali'iia. is nearly always almii'lant. aii' imiHirlant part of tlie residue. All iliese. Iii)\\e\er, arc still lij^hter than ;;i>id. and an- event nallv separatid trom ii liy menus iif their inferior s|(«H*iti«- ^nivity. through the a;;eii(\ n( walei- apiiiied in various ways, or linally l»y air applied l>y a liellows. I K.tbLIMi. The u'olil |ian. whieli is worke<| liy hand, i- Ilie simplest i-ontrivanee for separalinir th4' ;rold from the ;rnivel.s. The next eoiitrivaliee ;;i'ii- prally made use id" is the i-nidl«-. whieli is eonstrneted on essentially the same patterns as eradles .vhii-li «er«- us«h1 in Califitrnia and .\us- tralia in the earl.\' days of plaeer mining;. The eradle eonsists essen- tially of a lonjx. narrow \n>\. witli an np|MTand a lower eomparinienl. The (liKU- of the u|>per eompartinent i« pn-ferjibly made of metal, and is riddled with holes of convenient size. Intotliis upper compartment the i;ra\ els arc sliovided, and the whole <-ontrivanr-e is mo\ ed hai-k and forth upon the rockers on whicli it stands, and from uhi<'li it , into the lower coiii|tiirt meiit, while the coarser material, whii'h contains little or nopild. pas-ses out of the box as use- less ruhltish, or ■" tailinj;." as it i« technically called. The floor of the lower comifartmeiit is, in its sinipl«.*>t form. an inclined plane, tic sur- face of which is ronghentMl or corriisfiit*^! in various ways, such as liy the use of cleats or wo«Klen " riffl***." ••orninatol metal sheet. iii;,. other devices. A favorite methoestrv. r|>oii thi;* rou;:hened surface the line ;;old lodges, while the lijrhter material is <-arri ,".:i(t (iKOI.OOV OV THE YfKON OOI.O DISTIMCT. ALASKA. slifiiin <>( water. In llic I'dlcction of tlif fun- tf<>lais Ihi'ii- is ruiiNiilciaMf iMiin-fiiiratioii ..f irold. ami wlicii tiic ii\fr is sutVicii'lillv low tiicsi- ai-i-iiiiiiilalinii- ai<- workol liy llic iiiiiicis: hut ilic (•(iiiiparativfly small siz»'->f tlif Uie liar ^'ravi-ls are slniceil in tlic same way as the ;rnieli ;rrj»vels. the water Iteinjr raiseij to the licail of the sluice ill llie liiK kcts of an iimlerslioi water wliecl. (ifl.l II DK.iilXl.S. In till' irnl<'lies the conditions are .-ntin-ly "lifTereni. since the anionnt of water in I he si ream lied is usually small and can !m- .-asilx di\ cited if iiecis.sury, and the tiold oecui-s in a small cJiannel in the narrow gravels. These ^nhdi irravels vary in thickness from alHiut :i or I iVct to L'li or :;o feet. Their upper parts, however, an- invariably liarreii; the ■:old is all :' mml I'onccntratcd at the Inittoni. wliatexcr the thick- ness of the upper ^.navels ma\ 1«". The ;:nivcl w liich contains jjold ill wdi l^alllc■ '|U""li'.v is tci'hnieally ealle«l •* pay ;e and little-worn fra^'iiients of .st-liisl and (piarlz. SI III INll. W'lieii the oxerlyiiiLr harreii ;.'r,ivels an- not t<><> thick they aro stripped olV liy shoveliii;; and the pay dirl is laid luire. Then a loiitf, sli;:lilly inclined lioiiy:h, c.illed a sluice, which is liuilt in si'ciioiis of eipial len;rth, so as to lie easily taken d«iwn and tnin^pone-l irom one plai'e to another, is <'onst riicted of Iwiards. The lM.ard» for this pur- pose aie cut liy the miners from lo;:s with the aid of the whipsaw. Tlic ilitTeretif seetiotiH of this troiijrli or -luiei- are <'.illed lM>\es, and when these sluice ho.ves are ;irraiu.'ed con-ecutividx aiic) in |iositioii coinenieiit to the deposit of pa> dirt I he water Mow inj; in the bed of the ^tilch is partly diverted into them. ■»<■ that a <-<>ntinuous stream Hows Ihroiiirh the sluice and cmptii-H at ii^ lower end. The jiav V'taNel i>. then sl|o\e!ed into the lMi\es. mostly into the Up|M>r ones, so that the ;:ra\el will lie carried a^ f.ir a-> |»issihle U-forc Wciiit: ihiown out. The current is so rc;rnlatc<| that the liner ami li;:hter material and the sinallor uravelsare itnmeiliately c.irrn-«l out of the trough and deposited at its end. while tlie larye |Mdil>lcH and the heavier small imrticlcs sink to the hottoni and advance inoii- slowlj. The lar^iest METHODS OK MININO. 391 Jrtou*^ an- i<-iniiv('(l by a iniiicr wlio sianils n-ady witli a slmvi'l i-i ••lear lh<' )m<\.-> lit' siH'h inriiinlifainM's. Tlif lii'a\ii'.si nf all tlic niatr- riab» i» tIi«- ::o1<1, wliirli rniil> iis way tn the Ipniidin nf ilif ^liiici' To |in-v<-iit lliis fniiii i->caiiinir a scvii'> of slal> an- iiiMMlcil in tin- but loiii "f <.i' slaU*. or •'riffles," as ihcv arc calh'il. alTonla l(i. The fifllcs art' usually plapod jiaralli-li" ilic >i(ic?. ni' ilu- box ami fv»iinwl<' tuiiied uiT fmiii the sluice, the slats or lilllcs are taken up. ami the lieaviei- malTi;*! which has aiMMinuilaied i> caret'idly collecteil Tjie aicmini- latioii ir. \erv rich in ;rold, and also cinitains inairiielite. Iieiiialile. liiiionilc, galena, and i>yrile, as well as many t'lairnienis of the laiei- hfavv iiiiucrals. This material is ticin-i'ally waslicil by liami in a }ri»l«l {Kill, thus sceutinu a irreatei- concentration nt' tin' i.'"ld. but tht-n* still n-iiiaiiis some pyrite. iralena. liemaiiii'. and maLrnetite. whii-li can ih>l well be >eparateil from I ne ii<..>\ b\ wa^liinir. 'I'lie matriictic iron, which i-. known as "black sand" by the miin'i-. is i-x1ra<'1c<| with a small hand ma'.'nct. ananned 1<.\' the more ccunomicd mim'i>, and Ilifii yichi considerable free i^old. It i> iiii|Hirtaiit in l he cousin MM ion nf shijce-- l lial the ;.'radc be accu- ral*dv ao- a-iatol Willi a very lar^e proportion of valueless diri. uhile if the ;rrai|«- is t an i-xanrplc of thi» latt<-r mistake it ma\ lie mentioned iliai the lailini:^ u hieh liav«« l«f«'ii aaviiiiiiihitcd by one miner arc often >ucc e^viull^ lewaslicd by another. Ill ItMNi. AMI IIUIITIM;. The lalnir of removiii}.' the barren ;;iavel which oveilics the pa\- ilirt i> vcr\ ;rn-al, but ordinaril.v this is nndeiiakcn when the thick- iiesj. is not ctiiisidcrable. With im-rcasinu: iliicknessa point i> sonii r«*ai-li<'led of siiikin;,' shaft.o throiijrh the barr.-n material tn the pay dirt and extract inji this !«<« dirt hy means of lunnels or di'ifts alons.' the surface of the )ie«J-r being sunk, or at the face of the drift, which is JM-ing run, and thus the gravels are thawed out for some distance and can be easily shoveled up and taken to the surface. It takes a surprisingly small amount of wo feet, and 1!» feet in height, with only S feet of barren gravel iK-tween it and the surface; and yet this stood lirinly until spring, when the gr^avels thawed and the slope caved in. ■s. ^t