the fossils in question, was at that time (1860) well-known to belong, both in Great Britain and in Scandinava, to the primordial fauna, Mr. Barrande does not seem to have thought it necessary in his correspondence to refer to the very obvious remark of Mr. Billings.

Mr. Billings further showed in his paper in March, 1862, that fossils identical with those of the Georgia slates had been found by him in specimens collected by Mr. Richardson of the Geological Survey of Canada in the summer of 1861, on the Labrador coast, along the strait of Belisle: where Olenellus (Paradoxides) Thompsoni and O. Vermontana were found with Conocoryphe (Conocephalus) in strata which were by Billings referred to the Potsdam group. [See for the further history of these fossils the Geology of Canada, pages 866, 955, and Pal. Fossils of Canada, pages 11, 419.]

The interstratification of the dark-colored fossiliferous shales holding Olenellus with the red sandrock of Vermont, announced by Mr. Billings, was further confirmed by Sir William Logan in his account of the section at Swanton, Vermont [Geology of Canada, 281]. They were there declared to occur about 500 feet from the base of a series of 2200 feet of strata, consisting chiefly of red sandy dolomites (the so-called sandrock) containing Conocephalus throughout, while the shaly beds held in addition, the two species of Paradoxides (Olenellus) and some brachiopods. These beds, like those of Labrador, were referred by Logan and by Billings to the Potsdam group. The conclusions here announced were of great importance for the history of the Taconic controversy. The trilobites of primordial type, from Georgia, Vermont, which by Emmons were placed in the Taconic system, lying unconformably beneath a series of rocks belonging to the lower part of the New York system, were now declared to belong to the red sandrock group, a member of this overlying system. Much has been said of these fossils, as if they furnished in some way a vindication of the views of Emmons, and of the Taconic system; a conclusion which can only be deduced from a misconception of the facts in the case. Emmons had, previous to 1860, on lithological and stratigraphical evidence alone, called the Georgia slates Taconic, and placed them unconformably beneath the red sandrock. If now both he and Billings were right in referring the red sandrock to the Calciferous and Potsdam formations, and if the stratigraphical determination of Messrs. Perry

and G. M. Hall, confirmed by those of Logan, were correct, viz : that the trilobites in question occur not in a system of strata lying unconformably beneath the red sandrock, but in beds intercalated with the red sandrock itself, it is clear that these trilobites must belong not to the Taconic, but to the New York system. We shall return to the question of the age of these rocks.

We have seen that Prof. James Hall, in 1847, and again in 1859, referred trilobites regarded by him as species of Olenus to the Hudson-River group, or in other words to the summit of the second paleozoic fauna, while it is now well known that they are characteristic of the first fauna. In this reference, in 1847, Prof. Hall was justified by the singular errors which we have already pointed out in the works of Hisinger on the geology of Scandinavia. In his Anteckningar, in 1828, while the colored map. and accompanying sections show the alum-slates with Paradoxides to lie beneath, and the clay-slates with graptolites, above the orthoceratite-limestone, the accompanying colored legend, designed to explain the map and sections, gives these two slates with the numbers 3 and 4, as if they were contiguous and beneath the limestone, which is numbered 5. The student who, in his perplexity, turned from this to the later work of Hisinger, his Lethaea Suecica, found the two groups of slates, as before, placed in juxtaposition, but assigned, together, to a position above the orthoceratite-limestone. Thus, in either case, he would be led to the conclusion that in Scandinavia the alum-slates with Olenus, Paradoxides and Conocephalus (Conocoryphe) were closely associated with the graptolitic shales; and, upon the authority of the latter work, that the position of both of these was there above the orthoceratite-limestones, and at the summit of the second fauna. The graptolitic shales of Scandinavia were already identified with those of the Utica and Hudson-River formations of the New York system. The red sandrock of Vermont, containing Conocephalus, had been, both by Emmons and Adams, alike on lithological and stratigraphical grounds, referred to the still higher Medina sandstone; a view which, as we have seen, was still maintained and strongly defended by Adams. This was in 1847, and Angelin's classification of the transition rocks of Scandinavia, fixing the position of the various trilobitic zones, did not appear until 1854. Prof. Hall had therefore at this time the strongest reasons for assigning the rocks containing Olenus to the summit of the second fauna. Before we can understand his reasons for

maintaining a similar view in 1859, we must notice the history of geological investigation in eastern Canada. So early as 1827, Dr. Bigsby, to whom North American geology owes so much, had given us [Proc. Geol. Soc. I, 37] a careful description of the geology of Quebec and its vicinity. He there found resting directly upon the ancient gneiss, a nearly horizontal dark colored conchiferous limestone, having sometimes at its base a calcareous conglomerate, and well displayed on the north shore of the St. Lawrence at Montmorenci and Beauport. He distinguished moreover a third group of rocks, described by him as a "slaty series composed of shale and graywacke, occasionally passing into a brown limestone, and alternating with a calcareous conglomerate in beds, some of them charged with fossils * * * * derived from the conchiferous limestone." (This fossiliferous conglomerate contained also fragments of clay-slate.) From all these circumstances Bigsby concluded that the flat conchiferous limestones were older than the highly inclined graywacke series; which latter was described as forming the ridge on which Quebec stands, the north shore to Cape Rouge, the island of Orleans, and the southern or Point-Levis shore of the St. Lawrence; where besides trilobites, and the fossils in the conglomerates, he noticed what he called vegetable impressions, supposed to be fucoids. These were the graptolites which, nearly thirty years later, were studied, described and figured for the Geological Survey of Canada by Prof. James Hall; who has shown that two of the species from this locality were described and figured under the name of fucoids by Ad. Brongniart, in 1828. [Geol. Sur. Canada, Decade II, page 60.] Bigsby, in 1827, conceived that the limestones of the north shore might belong to the carboniferous period, and noted the existence of what were called small seams of coal in the graywacke series of the south shore, which substance I have since described in the Geology of Canada [page 525.]

In 1842, the Geological Survey of Canada was begun by Sir William Logan, who in a Preliminary Report to the Government, in that year [page 19], says "of the relative age of the contorted rocks of Point Levis, opposite Quebec, I have not any good evidence, though I am inclined to the opinion that they come out from below the flat limestones of the St. Lawrence." He however subsequently adds, in a foot-note, "the accumulation of evidence points to the conclusion that the Point Levis rocks are

superior to the St. Lawrence limestones." In 1845, Captain, now Admiral Bayfield, maintained the same view, fortifying himself by the early observations of Bigsby, and expressing the opinion that the flat limestones of Montmorenci and Beauport passed beneath the graywacke series. These limestones, from their fossils, were declared to be low down in the Silurian, and identical with those which had been observed at intervals along the north shore of the St. Lawrence to Montreal, [Geol. Journal, i. 455] the fossiliferous limestones of which were then well known to belong to the Trenton group of the New York system. The graywacke series of Quebec, which was still supposed by Bayfield to hold in its conglomerates fossils from these limestones, was therefore naturally regarded as belonging to the still higher members of that system; and, as we have seen, the green sandstone near Quebec, a member of that series, had already in 1842, been regarded by Emmons as the representative of the Oneida or Shawangunk conglomerate, at the summit of the Hudson-River group of New York.

It is to be noticed that immediately to the north-east of Quebec, rocks undoubtedly of the age of the Utica and HudsonRiver divisions overlie conformably the Trenton limestone, on the left bank of the St. Lawrence; while a few miles to the south-west, strata of the same age, and occupying a similar stratigraphical position, appear on both sides of the St. Lawrence, and are traced continuously from this vicinity to the valley of Lake Champlain. These moreover offer such lithological resemblances to the so-called graywacke series of Quebec and Point Lévis, (which extends thence some hundreds of miles north-eastward along the right bank of the St. Lawrence,) that the two series were readily confounded, and the whole of the belt of rocks along the south-east side of the St. Lawrence, from the valley of Lake Champlain to Gaspé, was naturally regarded as younger than the limestones of the Trenton group. It was in 1847 that Sir William Logan commenced his examination of the rocks of this region, and in his report the next year [1848, page 58] we find him speaking of the continuous outcrop "of recognized rocks of the Hudson-River group from Lake Champlain along the south bank of the St. Lawrence to Cape Rosier." In his Report for 1850, these rocks were farther noticed as extending from Point Lévis south-west to the Richelieu, and north-east to Gaspé, [pages 19, 32]. They were described as consisting, in ascending

sequence from the Trenton limestone and the Utica slate, of clay-slates and limestones, with graptolites and other fossils, followed by conglomerate-beds supposed to contain Trenton fossils, red and green shales and green sandstones; the details of the section being derived from the neighborhood of Quebec and Point Lévis, and from the rocks first described by Bigsby. As farther evidence with regard to the supposed horizon of these rocks, to which he subsequently (in 1860,) gave the name of the Quebec group, we may cite a letter of Sir William Logan, dated November, 1861, [Amer. Jour. Sci. II, xxxiii, 106,] in which he says "In 1848 and 1849, founding myself upon the apparent superposition in Eastern Canada of what we now call the Quebec group, I enunciated the opinion that the whole series belonged to the Hudson-River group and its immediately succeeding formation; a Leptona very like L. sericea, and an Orthis, very like O. testudinaria, and taken by me to be these species, being then the only fossils found in the Canadian rocks in question. This view supported Prof. Hall in placing, as he had already done, the Olenus rocks of New York in the Hudson-River group, in accordance with Hisinger's list of Swedish rocks as given in the Lethaa Suecica in 1837, and not as he had previously given it."

The concurrent evidence deduced from stratigraphy, from geographical distribution, from lithological and from paleontological characters, thus led Logan, from the first, to adopt the views already expressed by Bigsby, Emmons and Bayfield, and to assign the whole of the paleozoic rocks of the south-east shore of the St. Lawrence, below Montreal, to a position in the New York system above the Trenton limestone. While thus, as he says, founding his opinion on the stratigraphical evidence obtained in Eastern Canada, Logan was also influenced by the consideration that the rocks in question were continuous with those in western Vermont. Part of the rocks of this region had, as we have seen, originally been placed by Emmons at this horizon, while the others, referred by him to his Taconic system, were maintained by Henry D. Rogers to belong to the Hudson-River group; a view which was adopted by Mather and by Hall, and strongly defended by Adams, at that time engaged in a Geological Survey of Vermont, with which in 1846 and 1847, the present writer was connected.

As regards the subsequent paleontological discoveries in these