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 239 
 
 The Taconic and Lower Silurian Rocks of Vermont and 
 Canada. By Jules Marcou. 
 
 At the meeting of Oct. 17, 18C0, 1 bad the honor to read before the 
 Society extracts from three letters of M. Barrande, relating to the 
 stratigraphical position of the primordial fauna in North America. 
 Two of those letters were addressed to me, the third was a copy of a 
 letter to Professor Bronn of Heidelberg. I added a few remarks, and 
 the whole was published in the Proceedings, Vol. vii. p. 369, under the 
 title, "On the Primordial Fauna and the Taconic Systein, by Joachim 
 Barrande, tvith additional notes by Jules Marcou." 
 
 The views there exposed were received with little favor, at first, by 
 those geologists who, for the last fifteen years, have refused to recog- 
 nize the Taconic system, on the ground that it was not sustained by 
 any stratigraphical, paleontological, or lithological evidence. Ic was 
 hard for them to admit that the paleontological character at least was 
 against them, some going so far even as to deny the validity of pale- 
 ontological evidence in determining the age of strata. As the same 
 persons have long considered the lithological character " entirely 
 valuelesa," American geology was deprived of its two best supports, 
 and left entirely at the mercy of suppositions and conjectures. It was 
 evident, however, that the summary method, so frequently used, of 
 suppressing observations which did not agree with the views of those 
 regarded by some as the best and highest authorities on this continent, 
 could not succeed now, as it was impossible to rule out the science of 
 paleontology and its supporters. 
 
 Three months later, Mr. Logan of Montreal, in a letter to M. 
 Barrande (in which he inadvertently omitted to mention our Boston 
 pamphlet), admits that the views entertained by him on the rocks of 
 Point Levi and Georgia were erroneous, and tries to explain the 
 position of strata at Point Levi, putting together all the rocks found 
 there, as the " Quebec group of rocks." 
 
 Mr. James Hall, of Albany, in a letter to the editor of Silliman's 
 Journal, one month later, takes up the paleontological evidence, 
 letting it be understood that, if any mistake was made, it was due to 
 stratigraphy ; and mixing together, even more than Mr. Logan had 
 done, all the fossils found in the various places and strata at Point 
 Levi, he comes to the conclusion that '' M. Barrande's plan of succes- 
 sive Trilobitic faunaj " does not meet the case in hand ; and, without 
 giving any decisive opinion, he evidently leans toward the view that 
 he has always entertained, in common with the Professors Rogers, of 
 the Hudson River group. 
 
 This letter of Mr. James Hall appeared in Silliman's Journal of 
 March, 1861, together with a reprint of Mr. Logan's letter, and also a 
 
 '■^ '■■■■■"':/' 
 
240 
 
 part of our pamphlet, under the altered and false title * of, On the Pri- 
 mordial Fauna and the Taconic system of Emmons, in a letter to Prof. 
 Bronn of Heidelberg . 
 
 While these publications were in progress in America, M. Barrande, 
 in the Bulletin de la Socie'te' Ge'ologitjue de France, Vol. xviii. p. 203, 
 at the meetings of I^ov., 1860, and Feb., 1861, gave a long, elaborate, 
 and impartial memoir, entitled, " Documents anciens et noiweaux sur 
 la faune primordiale et le systcme Taconique en Ame'rique, with two 
 plates ; in which he gives at length the numerous, sagacious, and 
 profound observations of Dr. Emmons on the Taconic system, so long 
 kept in the background. 
 
 Professor Agassiz, who has contributed much to the enlargement of 
 our views and notions as to the great value of paleontological charac- 
 ters for the determination of the relative age of strata, desirous to assist 
 in the elucidation of the dilliculty, signalized with si'ch a masterly 
 hand by M. Barrande, sent me to Vermont and Canada to collect all 
 the specimens of fossils, and all the facts I could reach, for the benefit 
 of his Museum of Comparative Zoology. I give below a very sum- 
 mary resume of what I have seen, reserving all the detailed sections, 
 new fossils, and geological maps, ibr a longer memoir now in prepa- 
 ration. 
 
 I must begin by the statement that the Taconic system of Dr. 
 Emmons is the true base of the sedimentary strata in North America, 
 and that I agree in the main with all the observations, sections, and 
 descriptions of fossils of Dr. Emmons, who, in establishing the founda- 
 tion-stone of the pillar of American Stratigraphy, has given in his 
 different memoirs on the Taconic system the most difficult and impor- 
 tant geological works which have ever been produced on this side of 
 the Atlantic. 
 
 My researches were principally directed toward the upper part of 
 the Taconic series and the LoAver Silurian, and I give a tabular view, 
 showing the succession of groups of strata. This I was able to make 
 out for the vicinity of Georgia, St. Albans, Swanton, Highgate-Springs, 
 and Phillipsburgh, on the north-eastern shore of Lake Champlain. 
 
 Lorraine Shales. — This group, which has been also called Pulaski 
 Shales and Hudson River Group, does not occur at Snake Mountain, 
 nor in the vicinity of St. Albans, Georgia, Swanton, and Highgate. 
 Indeed, I did not find a single trace of this group anywhere on the 
 main land of Vermont, and I only saw it on the peninsula of Alburgh, 
 between Missisquoi Bay and Rouse's Point, where it presents the rocks 
 
 I 
 
 -.. 
 
 * I regret to say that this is the second instance since 1858 in which the editors of 
 Silliman^s Journal have not only appropriated letters belonging to me, but attrib- 
 uted them to persons who have had nothing whatever to do with them. 
 
241 
 
 THEORETICAL SECTION OF THE UPPER TACONIC AND I-OWER 
 SILURIAN ROCKS OF VERMONT. 
 
 :s 
 of 
 
 i 
 
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 H 
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 CO 
 
 PfS 
 
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 OROUPS. FKKT. j LOCALITIES, SUBDIVISIONS, AND t'OgglLB. 
 
 1 
 
 a. 
 
 B 
 
 a 
 
 LonnAiNE Shalbb. 
 
 j Alburgli Peninsula. 
 
 Utica Slatk. 
 
 40 1 Hijjhgate-Springs. 
 
 Trbnton Limestone. 
 
 60 
 
 Iligligute-Springs. 
 
 Black Kiveh Guoup. 
 
 40 
 
 •» At the base a blue limestone, very fossil- 
 iferous, with Ampyx Halli; 2 feet, lligh- 
 gate-Springs. 
 
 Calciperoub Sand- 
 stone. 
 
 700 
 to 
 900 
 
 .3. Gray and blue shales, containing nodules 
 of blue limestone, with fossils; about 150 
 feet. East of rUillipsburgh (llillings). 
 
 2. Blue and black limestone, very fossilifer- 
 ous (Bdihyurus Snff'oriii); about 300 feet. 
 Phillipsburgh ( Billings). St. Albans liay. 
 
 1. Gray and almost white limestone, con- 
 taining numerous veins of calc-spar, mar- 
 ble, and magncsiau limestone; about 300 
 feet. Phillipsburgh (Billings). St. Albans 
 Bay. Swanton. 
 
 s 
 
 a 
 
 Overlie the Taconic strata in discordance of stratification. 
 
 M 
 
 o 
 < 
 
 P5 
 u 
 
 ;3 
 
 roTSDAM Sandstone. 
 
 .300 
 to 
 
 400 
 
 4. Doloniitic conglomerate; 30 feet. Saint 
 Albans. 
 
 3. Red sandstone, with ConoeephnWes Adam- 
 si, C. Vutcanus ; 80 feet. Sa:- e's Mills. St. 
 Albans. 
 
 2. Dolomite; 150 to 200 fee- . • ixe's Mills. 
 Swanton. St. Albans. 
 
 1. White and red sandstone; feet. St. 
 Albans Bay. 
 
 i 
 
 s 
 
 B 
 » 
 
 LiNGULA Flags. 
 
 500 
 to 
 600 
 
 Brown, green, and blackish slates, with 
 Lin!iul(T, Orlhisina. Orthis^Chrondites, Grap- 
 tolites. Highgate-Springs. 
 
 Georgia Slates. 
 
 500 
 to 
 600 
 
 Gray, black, sandy slates, with Pnmdoxides 
 ( Olmelliis) T/iompsoni , P. Vermontana, Pel- 
 turn liolopi/ifa, Con. Tencer, Oholella cingu- 
 latn, Ortliisina festinaln, Ourterella antiquuta, 
 Chrondites, Fiingiis. W. Georgia. Swanton. 
 
 St. Albans Group. 
 
 2500 
 to 
 
 3000 
 
 Green, brown, and reddish slates, contain- 
 ing large lenticular masses of very hard, 
 whitish-gray limestone. Trilobites. St. 
 Albans. Georgia Centre. 
 
 Quartzitc, Conglomerates, and Ta'oose slates. 
 and belonging to the Lower Taconic 
 
 Between St. Albans and Fairfield, 
 
242 
 
 and fossils which characterize it at Sandy Creek, the typical locality 
 of Jerterson county, in the State of New York. 
 
 Utlca Slate. — The only locality where I met with these strata was 
 on the shore of Lake Champlain, a short distance behind the hotel of 
 Highgate- Springs. The thickness of what is not covered by the water 
 is forty feet; they have been overturned, and lie below the Trenton 
 Limestone. Dr. G. M. Hall, of Swanton, has found this group on 
 several of the islands in the middle of the lake. 
 
 Trenton Limestone, — This group, with its usual characters, is found 
 at Ilighgate-Springs. 
 
 Black River Group. — Comprising the Black River limestone, Birds- 
 eye limestone, and Chazy limestone. It is common to find now and 
 then, scattered along the whole line from Highgate-Springs to Bridge- 
 port, in small patches, lying in discordant stratification over the different 
 divisions of the upper Taconic, some beds of limestone of this group. 
 The thickness seldom reaches forty feet. They contain numerous 
 fossils characteristic of the group. Localities : Ilighgate-Springs, West 
 Georgia (near Mr. Parker's house), and Snake Mountain. At High- 
 gate-Springs the last bed of the Black lliver group is formed of a hard, 
 blue, grayish limestone, two feet thick, with Ampyx Ilalli, very fossilife- 
 rous, and constituting a very conspicuous and easy point de repere. 
 
 Calciferoiis Sandrock. — Until lately this group was not considered 
 of the importance that it really is, and it is due mainly to the researches 
 of Mr. Billings, of Montreal, that we have at last come to a true knowl- 
 edge and understanding of its characters, and the great place it occu- 
 pies in the Lower Silurian. In fact, the Calciferous Sandrock is the 
 base of the Lower Silurian, and contains half the thickness of the beds 
 composing the Lower Silurian of North America. In the Paleontol- 
 ogy of New York, by James Hall, Vol. i., thirteen or fourteen fossils 
 are described as being the only remains of organized beings found in 
 the Calciferous Sandstone, whereas now Messrs. Jewett^Billings, G. M. 
 Hall, Perry, Farnsworth, J. Richardson, J. Bell, and myself, have 
 succeeded in collecting from this group in Vermont, New York, Canada, 
 and at Belle Isle (Newfoundland), more fossils than in all the other 
 Lower Silurian groups put together, — that is to say, about twelve 
 hundred species, of which one hundred are new Trilobites. To any 
 one, however, acquainted with the different Silurian faunae of Europe, 
 it was evident that the second fauna of North America had not been 
 well worked out by the Paleontologist of New York, and that at least 
 a good half of it had escaped his hasty and superficial researches in 
 the field ; so that this discovery of numerous fossils belonging to the 
 second fauna in the Calciferous Sandstone, however sudden it might 
 be, was not unexpected to any one who has studied the different 
 memoirs of Barrande on the subject. 
 
 I 
 
 I 
 
24:i 
 
 A series of j?ray and bluo shales, (rontaininj^ nodulos of blue lime- 
 stono, with fossils oljaracturistit; of thii Cah-ifiTous Sandrofk, was dis- 
 covered in Au;i;iist last by Mr. Hillincrs, ten miles east of Phillips- 
 burjjh, on the road to Frelifrsbiirj»h, in Canada. Mr. Hillinjis saw it 
 lying over the limestone that forms the followintj; snbdivision, but was 
 unable to make out its thickness, and its junction with the lllack River 
 group, so that givinp; about one hundred and fd'ty feet for it is a mere 
 guess. 
 
 The second sul)division in descending the 8(!ries has been called by 
 Mr. Billings, in his interesting memoii", entitleil. On some RocLi and 
 FoKsits occurring near Phillipshuryfi, C<tn(vla Ed^l — (see the Canadian 
 Genloffhl, August, 1861, p. ;U0, Montreal,) — Blue, Thin-hcdded and 
 Nodidar Limestone. As Mr. Billings has given a good descri|)tion of it, 
 I will not repeat it here. The fossils are very numerous one mile east 
 of Phillipsburgh, and just behind the houses of the village of St. 
 Albans Bjy. The most characteristic are, Camerefla adci/'cra; Orthis; 
 Madnrea mn/nlina; Ophilda sordida, O. leixita, 0. complanata; Eccu- 
 liomphalus Canadensis, E. intortus, E. spiralis ; Pleurolomaria; Mur- 
 chisonia ; Hnlopeu ; Capului ; Orlhoreras ; Ci/rtoceras ; Nautilus ; 
 Lituites iinperator, L. Fanisworlhi ; Rathi/urus Saffordi, B. Cordai ; 
 Amp/lion Salteri ; Asaphus; Crinoids, Corals and Fucoids. 
 
 Below this subdivision, and passing gradually into it without any well 
 defined line of separation, is a series of gray, almost white, limestone, 
 containing numerous veins of calc-spar, white marble, and magnesian 
 limestone. Mr. Billings has called it Magnesian limestone, but as true 
 dolomite is found in large (Quantities in the middle of the Potsdam 
 Sandstone group, I think this name will have to be changed. The 
 fossils are rare in this lower subdivision, but Dr. G. M. Hall has found 
 in it some Cephalopods and Gasteropods half a mile south-east of Phil- 
 lipsburgh. This last subdivision was very plastic when first deposited, 
 for it re-covers in discordant stratification the slates, and sometimes 
 also the Potsdam Sandstone of the Taconic system, and follows all the 
 accidents of the Taconic strata, as though they were covered with a 
 sheet of paste or plastic clay. I regard it as the bottom rocks of the 
 Silurian system in North America, containing the second fauna of 
 Barrande. It can be observed at Phillipsburgh, on the shore line, east 
 of Swanton, and north of St. Albans Bay. It maybe that it forms the 
 marble of Middlebury and Rutland, but I am unable to speak with any 
 certainty, as it requires a special investigation, which I have been 
 unable to make. 
 
 The Calciferous Sandstone always lies in discordance of stratifica- 
 tion on the different groups of the Upper Taconic Strata ; sometimes 
 the discordance is 40°, generally 15° to 20°, and the direction of the 
 tetes de couches, or strike, as it is called in English, cuts always the 
 direction oi' the Taconic strata, at an average angle of 25°. 
 
244 
 
 Potsdam Sandstone. — In Vermont the Potsdam Snndstone has ex- 
 actly the Hame aspect and conipoHitlon as at I'otsdam, in the State of 
 New York. Near Saxe's Mills, a mile east of the Ilighgate-Sprin^js, 
 it contains two species of Couocej^hitlitcs, C. Adinnsi and C. Vulcnnus. 
 Being the cai)ping group of the Taconic in the reiwersement (overturn) 
 of the strata, it has been broken into pieces and narrow parallel 
 bands, which liave rested upon the more inclined strata in a sort 
 of unconfoi-mablo stratification, very apparent everywhere, scpieezing 
 the Lingula-flags and Georgia Slates near the point of contact, and 
 giving them for about two feet depth a sort of agitated structure 
 (structure lourmoitee). Theses narrow bands of Potsdam Sandstone 
 are numerous and well developed west of Mr. Parker's farm at (icorgia, 
 and also on the road l)etween St. Albans and Swanton ; at first they 
 appear to be interstratified with the Georgia Slates, but they are not 
 BO, and may be compared to the steps of a ladder placed over, or 
 even a little wedged into the (Georgia Slates and Lingula-ilags. This 
 group has been known for a long time in Vermont by the name of 
 Red SandrocL It is found all the way from Saxe's Mills to Western 
 Georgia. It forms the top and eastern side of Snake Mountain, con- 
 trary to the view of Dr. ICmmons, who refers these Snake Mountain 
 rocks to the Calciferous Sandstone. All the fossils found until now in 
 the Potsdam Sandstone of Vermont and New York are of primordial 
 form ; and there is also a great break and dis<'ordance of stratification 
 between this group and the Lower Silurian ; and I think the opin- 
 ion I first expressed one year ago is fully justified by paleontological 
 and stratigraphical evidences. 
 
 Below the Potsdam Sandstone lie great masses of slates, four or five 
 thousand feet thick, which for convenience I should divide into three 
 parts. No regular line of division can be traced between these three 
 groups, as the strata pass from one to the other without any well 
 marked ditl'erence ; it is merely for the fossils, and as a matter of con- 
 venience, that I propose the division. 
 
 Lingula-Jloffs. — The upper group, or Lingula-flags, is formed of 
 brown, green, and blackish slates, five or six hundred feet thick, with 
 numerous lines of cleavage, cutting the strata in all sorts of direc- 
 tions. In some parts the fossils are very numerous, and I found at 
 Highgate-Springs, where I first saw them, in company with Dr. Hall, a 
 quantity of Lingulce, Ortliis, Orthisina, and Chrondites. The Lingula 
 is new, and the Orthisina is nearly related to, if not identical with, 
 an Orthisitia quite common in the Lingula-Hags of Wales in Great 
 Britain. Mr. Billings informs me that since my visit there he found at 
 Phillipsburgh some Graptolites, in slates near the shore of the lake, 
 which I consider as of the upper group, or Lingula-flags. 
 
 Georgia Slates. — The middle group, or Georgia Slates, is composed 
 
 .1 
 
.. 
 
 245 
 
 of pray and black sandy slates, somotinips passing into a tnie yellowish 
 siindstont!, with nodules ofoxidu of iron, and spots ot'reil oxide of iron 
 on some slates. Tiiickncss, live to six imndred ieet. In tiiis division, 
 tifty yards from tlie liouse of Mr. Xoali E. I'arker, in West (leorjjia, 
 the eeiehratcd (Jeorjiia Trilolntes wc^re found. They were discovered 
 accidentally, about six years ajjo, by Mr. Parker, in (puirrying large 
 slates tor a floor. Having (bund one Trilobite, and not knowing what 
 it could be, Mr. Parker showtid it to the schoolmaster of the village, 
 who wrote at once to the late Zadock Thompson, of TJiirlington, then 
 State Geologist of Vermont. ]\Ir. Thompson immediately visited the 
 ([uarry, and made a collection of several specimens and species; unfor- 
 tunately ho died a short time after, without publishing anything about 
 this discovery. The specimens having been jjlaotMl in the hands of 
 Mr. fJames Hall, that jjaleontologist described and figured them in a 
 memoir under the very odil title of Trilohilea nfthc. Shales of the Hud- 
 son Rh'cr Group: Albany, 1H(;(». It was this title that startled Mr. Bar- 
 rande so much, anil was the occasion of bringing once nxore before the 
 world, and this time not to be sujjpressed, the Taconie system of my 
 learned friend Dr. Kinmons. Mr. James Hall does not give a single 
 geological fact to sustain his opinion of the Hudson River group; he re- 
 gards it as a matter of eourac;, beyond all doubt; and in order to give it 
 a sanction which will make all discussion useless, he calls to his support 
 the testimony of Mr. Logan (who, by the way, has never visited the 
 locality), and adds, as overwhelming proof, that " it would be quite 
 superfluous for him to add one word in support of the opinion of 
 the most able stratigraphical geologist of the American continent." 
 The only other geological indication tli;it I have been able to find is in 
 SiUiman's Journal for January, 1861, p. I'lh, where Mr. James D. 
 Dana calls the Georgia rocks " metamorphic bla(.'k slates." I regret 
 to say that all these statements and opinions are erroneous; there is no 
 trace of the Hudson River (/roup at Georgia, nor at any other place in 
 the vicinity, and I was unable to find indications of metamorphisra in 
 any of the rocks tlwre, for at least three miles around the quarry of 
 Mr. Parker. The fossils are not numerous, with the exception of the 
 Chrondkes ; and the Trilobites are certainly much less common there 
 than the Paradoxides Harlani in the (juarry of Mr. Haywood at 
 Braintree. I found at West Georgia the three Trilobites described by 
 Mr. James Hall, Paradoxides (Olenellus) Thompsoni, P. Vermonlana, 
 Peltura holopi/rja ; and besides Obolella cingulata, a Fungus, Chron- 
 dltes, and a Bryozoon, related to the Graptopora sociatis (Salt.), all 
 primordial fossils. 
 
 Until this summer West Georgia was the only place for these Trilo- 
 bites. Two other localities have been added in the last two months. 
 Dr. G. M. Hall and Rev. J. B. Perry have found the P. Thompsoni, 
 
246 
 
 P. Vermontana, Obolella cingulata, Orthisina festinata, Camerella anti- 
 quata, Conocephnlites ^eucer, and Ch-ondites, a mile and a half east of 
 the vi^'age of Swanton ; and Mr. James lliohardson has collected 
 specimens of the same Paradoxides farther east, at L'anse au Loup, 
 on the north shore of the straits of Belle Isle, Labrador ; (see Neiv 
 Species of Lower Silurian Fossils, by E. Billings. Montreal, Nov., 1861). 
 
 Saint Albans Group. — The road between St. Albans and Georgia, 
 and thence from Georgia to Mr. Parker's house, lies all the way on 
 green, brown and reddish slates, containing now and then large lenti- 
 cular masses of very hard, whitish-gray limestone. Thickness, be- 
 tween twenty-five hundred and three thousand feet. I did not find 
 any fossils, although I heard of one specimen of Trilobite picked up 
 behind the town of St. Albans by an inhabitant, nor was I able to 
 see that specimen. The reddish slates, which are not well developed 
 in Vermont, as regards the red color of the rocks, lie at the base of 
 the upper Taconic strata. Tiicy are worthy of notice, as containing 
 the veins of sulphuret and copper pyrites of the Acton mines, in 
 Canada, and the Bruce and Wallace mines of Lake Huron. 
 
 Below the St. Albans group are ([uartzite, conglomerates, talcose 
 slates, clay slates, mica-schist, and gneiss, with intercalation of beds 
 and lenticular masses of crystalline limestone, resting on the unstrati- 
 fied and oldest crystalline rocks of the AVhite ^Mountains, and compos- 
 ing the Lower Taconic system. Dr. Emmons did not i)ut in his Lower 
 Taconic the mica-schist and gneiss, which form the central and east- 
 ern part of Vermont, but on a close examination of the subject in the 
 vicinity of Rutland, Bolton, and Island Pond, I have come to the con- 
 clusion that these rocks have a stratified and sedimentary origin, and 
 that they are the base of the Taconic system. All the strata of the 
 Lower Taconic system are more or less metamorphic, especially at the 
 base ; — the metamorphism produced by the action of mineral springs 
 during the deposits, together with pressure caused by the divers dislo- 
 cations to which they were aflerward submitted. The Lower Taconic 
 is at least ten thousand feet thick, making fifteen thousand feet the 
 minimum for the Taconic system of Vermont. It is difficult to give 
 the thickness of the strata with any exactness, as the Green Mountains 
 present a fan-like structure, similar to that of the Alps and Pyrenees. 
 
 Twelve years after the discovery and description of the Taconic 
 system, Mr. Logan, having met with some of the Taconic rocks on the 
 southern edge of the Laurcntine Mountains, between the Saguenay 
 River and the Bruce mine on Lake Huron, and overlooking entirely 
 the researches of Dr. Emmons, proposed to introduce into the table of 
 the American strata two new systems, which he called the lMure)ttian 
 and Iluronian systems ; (see Esquisse Geologique du Canada, Paris, 
 1855). The Laurentian system is composed of the Lower Taconic, to 
 
J 
 
 247 
 
 which are added all the unstratified crystalline rocks forming the centre 
 of the Laurentine Mountains, such as granite, syenite, diorite and 
 porphyry, mixing together strata and eruptive rocks, an attempt which 
 was unexpected from a stratigraphical geologist. His Huronian 
 system is formed of a mixture of the St. Albans group of the Upper 
 Taconic, with the Triassic rocks of Lake Superior, the trap native- 
 copper bearing rocks of Point Keeweenaw, and the dioritic dyke con- 
 taining the copper pyrites of Bruce mine on Lake Huron. 
 
 The different dislocations which have affected the rocks of the 
 vicinity of Quebec have not brought to light the complete series of 
 the Taconic nor of the Lo. dr Silurian, and the difference of opinion 
 that exists between Mr. Logan and myself is partly owing to this 
 want. In his Remarks on the Fauna of the Quebec Group of Rocks and 
 the Primordial Zone of Canada, Jan., 1861, and in his Considerations 
 relating to the Quebec Group, May, 1861, Mr. Logan gives the following 
 series for the vicinity of Quebec : — 
 
 u^. — Dark gray shales and sandstones ("Hudson River). 
 
 u^ — Black shales (Utica). 
 
 b. — Limestone (Birdseye, Black River, and Trenton). 
 
 ► Quebec Group. 
 
 q". — Sandstone and red shales (Sillery). 
 
 q". — Red and green shales. 
 
 q''. — Green and gray shales a id sandstones. 
 
 q^ — Sandstones and magnesian conglomerates. 
 
 q^ — Green shales. 
 
 q^ — Magnesian conglomerates and shales. 
 
 p^— Sandstones. I Potsdam, 
 
 p^ — Black shales and limestones. > 
 g. — Gneiss (Laurentian). 
 
 All the fossils found al Point Levi are placed by Mr. Logan in a 
 single group of strata, which he calls the Quebec group. He speaks also 
 several times of shales and limestones beneath the Quebec group, 
 which he considers as deep-water deposits of the Potsdam Sandstone. 
 Unhappily he does not give any precise localities or section at Quebec 
 or Point Levi where that Potsdam may be found, and I was unable 
 to discover what strata he thus names. But wherever these strata 
 may be located, he says that he found no fossils in them in Canada, 
 " but that the shales resemble those in which Oleni have been found in 
 Georgia." So that Mr. Logan considers the Georgia Slates and the 
 Potsdam Sandstone as the same group, one being a deep-water deposit 
 and the other a coast deposit. I will only remark that at Mr. Parker's 
 house, in Georgia, the two groups are found one above the other. 
 
 Mr. James Hall, in his last descriptions of the Georgia Trilobites 
 (Thirteenth Annual Repurl of the Stale Cabinet of Natural History 
 
248 
 
 of New York, 1861), overlooking the remarks of Mr. Logan on the 
 Georgia Slates, includes the Georgia Slates in the Quebec group, adding 
 new contusion to an already very difiuse explanation. 
 
 In a tabular view of my observations in the vicinity of Quebec, we 
 shall have the following theoretical section : — 
 
 THEOUETICAL SECTION OF THE KOCKS OF THE VICIXITY OF 
 
 QUEBEC. 
 
 OliOL'l'S. 
 
 FEET. 
 
 LOOALIIIES, SUBDIVISIONS, FOSSILS. 
 
 •< 
 
 H 
 
 on 
 
 K 
 
 U 
 
 o 
 
 Lorraine Shales. 
 
 
 Not seen. 
 
 § 
 
 • 
 
 Utica Slate. 
 
 40 
 
 Montmorency Falls. 
 
 Tbemton Limbstoke. 
 
 30 
 
 Jlontmorency Falls, Beaufort, and Indian 
 Lorette. 
 
 Black Biver Group. 
 
 
 Not seen. 
 
 Calciferocs Sand- 
 stone. 
 
 600 
 
 a. Blue schistose marls, interstratifled wi(h 
 conglomerates and blue limestone. Com- 
 pound Gmptolites. Citadel, City of Que- 
 bec, and Point Levi. 
 
 6. Gray slates, sometimes blackish, with 
 alternation of yellow sandstone, magne- 
 sian conglomerate, and 20 or 30 feet of 
 gray limestone. The limestone is very 
 iossiliferous : Bathyurus Saffordi, B. Cor- 
 tlai, EccuUomvhalus Canadensis, Camerdla 
 calcifera, etc. ferre du Cure at Point Levi. 
 
 The lower part of the group is not visible. 
 
 M 
 
 z 
 o 
 o 
 < 
 
 Potsdam Sandstone. 
 
 
 Not seen. 
 
 1 
 
 i 
 
 a 
 
 LiNGULA Flags. 
 
 
 Not seen. 
 
 Georgia Slates. 
 
 Not seen. 
 
 St. Albans Group. 
 
 3000 
 
 a. Green, brown, and black slates of Gil- 
 mor wharf, east of Point Levi, and also 
 on the road to Arlaka. Containing the 
 large lenticular mass of whitish gray 
 limestone of La Redoute or Guay quar- 
 ries. The Kedoute limestone contains: 
 Dikellocephalus, Conor.ephaliles, Menoceph- 
 alus, Arionellus, Orthisina, Capulus and Cri- 
 noUts. 
 
 b. Sillery and Chaudi6re red slates and 
 sandstones. 
 
 4 
 
 Quartzites of Montmorency Falls, 
 mined. 
 
 Its position in the Lower Taconio still undeter- 
 
249 
 
 Lorraine Shales or Hudson River Group. — Mr. Logan, in his section 
 from Montmorency to the Island of Orleans, regards the bed of the 
 St. Lawrence as entirely formed by dark gray shales and sandstones, 
 which he considers of the age of the Hudson River group. Having 
 no diving apparatus at my disposition, I was unable to follow him to 
 the bottom of the St. Lawrence. If this group really exists in the 
 vicinity of Quebec, it will be brought out by a careful examination 
 of all the strata between Ste. Foix and Indian Lorette. 
 
 Utica Slates. — Dr. Emmons, in his Geolor/y of New York, 1842, p. 
 117, refers the slates of Montmorency Falls to the Utica Slates, having 
 found there the characteristic Trilobites of Triarthus Beckii. Dr. 
 Bigsby also calls them Utica slates {On the Geolor/y of Quebec and its 
 environs, 1853), and so did, after their example, Mr. Logan. In my 
 short exploration of 1849, I erroneously considered those black slates 
 of Montmorency Falls as older than the Trenton Limestone forming 
 the summit of the falls ; but at my recent visit I found the opinion of 
 the geologist above named to be correct. 
 
 Trenton Limestone. — The thirty feet of limestone at the top of Mont- 
 morency Falls, and at the foot of the precipice immediately in contact 
 with the quartzite, are of the Trenton Limestone age, as Mr. Logan has 
 stated in his description of Montmorency formations ; fossils are very 
 abundant in both places. 
 
 Black River Group. — I was unable to refer any strata to the subdi- 
 visions of this group. Mr. Logan does not give any special localities 
 for it, having only put it in his diagram and theoretical section without 
 other notice. 
 
 Calciferous Sandstone. — This group is composed, at the summit, of 
 blue schistose marls, interstratified with thin bedded limestonos, blue 
 and sometimes almost black, and large masses of conglomerate, the size 
 of the rounded pebble attaining even that of the true boulder. In this 
 upper part, especially in the cliff on the road from the ferry to Notre 
 Dame church at Point Levi, are found a quantity of the celebrated 
 compound Graptolida;. The citadel and the old town of Quebec are 
 built on it. Then there is a succession of gray slates, sometimes 
 almost black, with alternations of yellowish coarse sandstone, magne- 
 sian conglomerate, and twenty or thirty feet of a gray limestone, brec- 
 ciated, hard, and very fossiliferous. I did not see the lower part of 
 the Calciferous Sandstone ; perhaps it has been concealed by the dislo- 
 cations, or was never deposited in this part of Canada. The thick- 
 ness of the whole is about six hundred feet. This number appears at 
 first a small one, but if we take into consideration the numerous fold- 
 ings of this deposit, and also the narrow band it forms, it will be seen 
 to be sufficient, for the ridge which it forms is never more than a mile 
 and a half in width, cxtcndiii'r from Quebec to the Plains of Abra- 
 
250 
 
 ham, Claremont, and Cape Rouge, the extremity of Point Levi, and a 
 little of the clitf west of it, and finally a part of the island of Orleans. 
 It rests unconformably upon the different subdivisions of the St. 
 Albans group ; that is to say, on the Taconie slates of Gilmor Wharf, 
 the lledoute limestone, and the Sillery and Chaudi^re red rocks. 
 This uneonformability is somewhat difficult to make out, because the 
 strata have been so dislocated, folded, and squeezed, that they oflen 
 appear as if they lay below the St. Albans group instead of being 
 above, as they are in fact. But patient and numerous observations 
 made with a theodolite, or a good compass, will clear up all the 
 difficulty. 
 
 In Remnrkson the Fauna of the Quebec Group, &c., Mr. Logan gives 
 some details, calling separate exposures or outcrops. A, A^, A^, A", 
 A*, B', B", and B', and considering the whole as one group of strata. 
 I tried without success to understand his explanation when I was at 
 Point Levi, his memoir in one hand and mv hammer in the other. 
 The only thing I was able to make out was : 1st, that what he calls the 
 more northern outcrop. A**, was mainly the quarries of the Notary 
 Guay, or the Redoute limestone ; I say mainly, for other strata may be 
 included in it, of limestone and conglomerate which surround the len- 
 ticular mass of the Redoute* ; 2d, that his outcrops A\ A'', A*, B', B^, 
 and B'', were a single group of strata, with repetition of several beds 
 by folding, situated between the churches of St. Joseph and Notre 
 Dame, a little east of that line, and in a parcel of ground called by 
 the Canadians Terre du Cure (land of the Curate of St. Joseph) ; 3d, 
 the cliff A is exposed very well on the road leading from the ferry to 
 Notre Dame church. 
 
 Mr. Logan includes also in his Quebec group the Sillery red shales 
 and sandstones, the whole having, perhaps, a thickness of five or seven 
 thousand feet, and regards it as the equivalent of the Calciferous Sand- 
 stone and Chazy Limestone. The Chazy Limestone is a small subdi- 
 vision of the Black River group, and I did not see it, or any equiva- 
 lent of it. The cliff A is in part subdivision a of the Calciferous 
 Sandstone of my tabular view. The outcrops A^ A^, A*, B\ B', and 
 B*, form entirely my subdivision h ; I will call them strata de la terre 
 du Cure. The fossils are very numerous in several beds, especially in 
 some of the brecciated limestone ; the most common are : Bathyurus 
 Saffordi, B. Cordai, B. bituberculatus, B. quadratus ; Cheirurus Apollo, 
 C. Eryx ; Aynostus ; Ecculiomphalus Canadensis, E. intortus ; Holopea 
 dilucula ; Pleurotomaria ; Murchisonia ; Orthoceras; Cyrtoceras; Orthis; 
 Camerella calcifera, etc., all belonging to the second fauna. Mr. Logan 
 
 ^ 
 
 * So called by the older Canadians because there was a Redoubt there during the 
 last French war. 
 
 i 
 
251 
 
 names several fossils, especially Trilobites, BatJtyurus and Menocepha- 
 lus, which are common to the outcrops AS A*, A*, BS B", and B^ (strata 
 de la terre du Cure) and the outcrop A^ but I did not find any ; it 
 may be that some boulders and pebbles of A", or la Redoute Limestone, 
 are enclosed in the conglomerates of the different beds of the strata de 
 la terre du Curd. 
 
 The outcrop A* is entirely distinct from the others. It is true that 
 La Redoute is almost entirely surrounded by small bands of Calcife- 
 rous Sandstone, that form as it were the frame of a small island, but 
 such accidents are not rare in much disturbed and dislocated coun- 
 tries, and it is not difficult to sec that La Redoute is independent of 
 all the other hills of Point Levi, forming a conspicuous landmark, 
 which can be seen from all the environs of Quebec, and having a 
 north and south or meridian direction, in common -with the whole of 
 the Green Mountain system, which put an end to the Taconic deposits, 
 •while the other hills of Point Levi and Quebec run north-east and 
 south-west. The strata de la terre du Curd do not include, I think, all 
 the Calciferous Sandstone, as it is developed in Vermont and Phillips- 
 burgh ; the lower part, or white limestone of Phillipsburgh shore, is 
 wanting here. 
 
 Potsdam Sandstone. — I did not see any rocks in the vicinity of 
 Quebec which I can refer to this capping group of the Taconic 
 system. 
 
 Lingula-Jlags. — Not seen. 
 
 Georgia Slates. — Not seen. 
 
 <S^ Albans Group. -^ This lower group of the upper Taconic is well 
 developed on the south shore of the St. Lawrence, which it occupies 
 almost entirely, with the exception of one or two miles at Point Levi. 
 It extends far into the interior. Its thickness is at least three thousand 
 feet. The upper part is composed of green, brown, and black slates, 
 affected by numerous lines of cleavage, and can be seen very well 
 developed near the Gilmor Wharf, east of Point Levi, also on the road 
 from St. Joseph's church to Arlaka, at one mile from the church. I 
 consider the Redoute Limestone, or quarries of the Notary Guay, as 
 forming a lenticular mass inclosed in them, similar to one that I 
 observed at St. Albans. I did not find any fossils in the slates, except 
 the Chrondites, so common and characteristic of all the upper Taconic 
 slates. The Redoute Limestone presents a highly interesting fauna. 
 The strata are almost perpendicular, with a direction almost due north, 
 and a deviation to the east of 5° or 7°. The stratification is indistinct, 
 as it always is with lenticular masses. The limestone is gray, almost 
 white, very hard, sometimes oolitic, with little veins of chalcedony. Its 
 whole thickness cannot be less than eighty or one hundred feet. In 
 some of the strata fossil remains are numerous, but composed only of 
 
262 
 
 fragments, chiefly heads and pyffidia of Trilobites ; and it is very diflicult 
 to obtain specimens on account of the great hardness of the stone. I 
 succeeded, however, in collecting the following species : Conocej)Tia- 
 lites Zenkeri; Dikellocephalun moffnijicm, D. planlfrons, D. inegalops, 
 D. cristatus ; pygidia of a Dikellocephalus not named by Billings, but 
 figured No. 11 and 12; Arionellus cylindriciis, A. suhclavatus ; Meno- 
 cephalus Sedgetoicki, Menocephalus gldbosus ; a large Capulus, an 
 Orthisina, and the stems and even the foot of a Crinoid. 
 
 All the known species of the Rcdoute limestone have been described 
 in a masterly manner by Mr. Billings in his memoir, On some species 
 of Fossils from the limestone near Point Levi, opposite Quebec, August, 
 1860. I did not find the Dikellocephalus Belli and D. Oweni, nor 
 Agnostus Americanus, A. Orion and A. Canadensis, which Mr. Bil- 
 lings describes as part of his fauna of Limestone No. 1. Without 
 touching the stratigraphical question, Mr. Billings separates the species 
 under the heads of Limestones Nos. 1, 2, 3, and 4. His numbers 2, 3, 
 and 4, are evidently what I call the Calciferous Sandstone strata, and 
 his No. 1 represents in part the Redoute Limestone. I say in part, for, 
 perhaps, he has put in No. 1 some specimens resembling those of the 
 Redoute Limestone, especially when broken in very small fragments, 
 that really belong to the strata de la terre du Curd. For instance, I 
 found a good specimen of his Bathyurus bituberculatus, not at the 
 Redoute, but at the terre du Cure', and I did not find a single speci- 
 men or trace of the genus Bathyurus in the Redoute Limestone ; con- 
 sequently my observations in the field do not lead me to consider the 
 genus Bathyurus as a primordial one ; it belongs exclusively to the 
 lower part of the second fauna. According to my observations, the 
 fauna of the Redoute Limestone is entirely primordial, without any 
 mixture whatever of fossils of the second fauna, being limited to the 
 genera Conocephalites, Dikellocephalus, Arionellus, Menocejjhulus, 
 Captdus, Orthisina, and a Crinoid, which characterize the primordial 
 fauna in America as well as in Europe. 
 
 The inferior part of the St. Albans group is formed by what has 
 been called the Sillery and Chaudiere red shales and sandstones, in 
 which no fossils have as yet been found. In Canada this part of the 
 group is much more developed than in Vermont, or perhaps the differ- 
 ence in colors is due to metamorphism in Vermont. 
 
 Finally, there is a beautiful quartzite at the falls of Montmorency, 
 which Mr. Logan, for an unknown reason, continues to call Lauren- 
 tian gneiss. It forms the bed of the Montmorency river and the 
 chasm of the precipice. It is indistinctly stratified by beds from ten 
 Kfl>r to twelve feet thick, very pEkfk and compact, and has all the characters 
 of a metamorphic sandstone or true quartzite. Direction or strike N. 
 45° E. to 8. 45° W., dipping south-east at an angle of 80 or 85 
 deiirces. 
 
253 
 
 4 
 
 Such is the series of rocks seen by me in the vicinity of Quebec. 
 Mr. Logan says, " from the physical structure alone no person would 
 suspect the break that must exist in the neighborhood of Quebec ; and 
 •without the evidence of the fossils every one would be authorized to 
 deny it ; " thus throwing on Paleontology all the mistakes made atid all 
 the difficulties accumulated in his Quebec Group. I ask permission to 
 say that the Stratigraphical and Lithological differences between the 
 Silurian and Taconic rocks of the vicinity of Quebec are to me at 
 least as great and as plain as the Paleontological ones ; and that I find 
 no facts whatever which show any conflict between Paleontology and 
 Stratigraphy. 
 
 It is doubtful if all the shales between the chasm of Montmorency 
 Falls and the waters of the St. Lawrence are of the Utica Slate age ; 
 the Graptolitas bicornis and G. pristis are found in the black shales 
 near their contact with the Trenton Limestone, but as yet no fossils 
 have been found in the gray shales. In the ravine east of the Falls, 
 there is probably a fault between the black and gray Shales ; the 
 dipping of the Trenton Limestone, the black Shales and gray Shales, 
 disagrees, and varies from fifteen to eighty degrees, in a space of less 
 than 150 feet. I am inclined to consider the gray Shales as the upper 
 part of the Calcif'erous Sandstone group, but it will require further 
 investigations in the field to determine the true stratigraphical struc- 
 ture of Montmorency Falls. 
 
 4 
 
 (•