Richard Harlan, the cast of a large trilobite occurring in a silicious slate, which was in the collection of Francis Alger, of Boston, and, it was supposed, might have come from Trenton Falls, New York. Dr. Green, who at once pointed out the fact that the rock was wholly unlike any found at this locality, declared the fossil to resemble greatly the Paradoxides Tessini, Brongn.,-the former Entomolithus paradoxus of Linnaeus, from Westrogothia, -and named the species P. Harlani. [Amer. Jour., Sci. I, xxv, 336]. In 1856, the attention of Prof. William B. Rogers was called to a locality of organic remains in Braintree, on the border of Quincy, Massachusetts, where, on examination, he at once recognized the Paradoxides Harlani in a silicious slate similar to that of the original specimen. This was announced by him in a communication to the American Academy of Sciences [Proc., vol. iii], as a proof of the protozoic age of some of the rocks of eastern Massachusetts. Prof. Rogers then called attention to the fact that this genus of trilobites is characteristic of the primordial fauna, and noticed that Barrande had already remarked that, from the casts of P. Harlani, in the London School of Mines, and the British Museum (which had been made from the original specimen, and distributed by Dr. Green), this species appeared to be identical with P. spinosus from Skrey in Bohemia.

In 1858, Salter found in specimens sent to the Bristol Institution, in England, by Mr. Bennett, of Newfoundland, from the promontory between St. Mary's and Placentia Bays, in the southwestern part of the island, a large trilobite, described by him as Paradoxides Bennettii [Geol. Jour., xv, 554], which appears, according to Mr. Billings, to be identical with P. Harlani. On the same occasion Salter described under the name of Conocephalites antiquatus, a trilobite from a collection of American fossils sent by Dr. Feuchtwanger of New York to the London Exhibition of 1851. This was said to occur in a boulder of brown sandstone from Georgia, and, as I have been informed by Dr. F., was found near the town of Columbus in that state.

The slates of St. John, New Brunswick, and its vicinity have recently yielded an abundant fauna, examined by Prof. Hartt, who at once recognized its primordial character. This conclusion was first announced, on the authority of Prof. Hartt, in a paper by Mr. G. F. Matthew, in May 1865 [Geol. Jour., xxi, 426]. The rocks of this region have afforded two species of Paradoxides, and fourteen of Conocoryphe, together with Agnostus and Micro

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discus, all of which have been described by Prof. Hartt. It may here be noticed that in 1862, Prof. Bell found in the black shales of the Dartmouth valley, in Gaspé, a single specimen of a large trilobite, which, according to Mr. Billings, closely resembles Paradoxides Harlani, but from its imperfectly preserved condition cannot certainly be identified with it. [Geol. Canada, 882].

The geological examinations of Mr. Alexander Murray in Newfoundland since 1865, have shown that the south-eastern part of that island contains a great volume of Cambrian rocks, estimated by him at about 6,000 feet in all. No traces of the Upper Cambrian or second fauna have been detected among these, but some portions contain the Paradoxides already mentioned, while others yield the fauna which Mr. Billings has called Lower Potsdam. This name was first given in an appendix (prepared by Sir W. E. Logan,) to Mr. Murray's report on Newfoundland for 1865, published in 1866 [page 46; see also Report of the Geol. Survey of Canada for 1866, page 236.] The Lower Potsdam was there assigned a place above the Paradoxides beds of the region, which were called the St. John group, the fossiliferous strata of St. John, New Brunswick, being referred to the same horizon; which corresponds to the Menevian of Wales, now recognized as the summit of the Lower Cambrian. The succession of the rocks containing these two faunas in south-eastern Newfoundland is not yet clear; the Lower Potsdam fauna is regarded by Mr. Billings as identical with that found on the strait of Bellisle, at Bic, (on the south shore of the river St. Lawrence, below Quebec,) at Georgia, Vermont, and at Troy, New York; but in none of these other localities is it as yet known to be accompanied by a Menevian fauna. The trilobites hitherto described from these rocks belong to the genera Olenellus, Conocoryphe and Agnostus; neither Paradoxides, which characterizes the Menevian and the underlying Harlech beds in Wales, nor Olenus, which there abounds in the rocks immediately above this horizon, having as yet been described as occurring in the Lower Potsdam of Mr. Billings. Future discoveries may perhaps assign it a place below instead of above the Menevian horizon.

The characteristic Menevian fauna in and near St. John, New Brunswick, is found in a band of about 150 feet, towards the base of a series of nearly vertical sandstones and argillites, underlaid by conglomerates, and resting upon crystalline schists,

in a narrow basin. The series, the total thickness of which is estimated by Messrs. Matthew and Bailey at over 2000 feet, contains Lingula throughout, but has yielded no remains. of a higher fauna. The same Menevian forms have been found in small outlying areas of similar rocks, at two or three places north of the St. John basin, but to the south of the New Brunswick coal-field. To the north of this is a broad belt of similar argillites and sandstones, which extends south-westward into the state of Maine. This belt has hitherto yielded no organic remains, but is compared by Mr. Matthew to the Cambrian rocks of the St. John basin, and to the gold-bearing series of Nova Scotia, [Geol. Jour. xxi, 427,] which at the same time resembles closely the Cambrian rocks of southeastern Newfoundland. This was remarked by Dr. Dawson in 1860, when he expressed the opinion that the auriferous rocks of Nova Scotia were "the continuation of the older slate series of Mr. Jukes in Newfoundland, which has afforded Paradoxides," and probably the equivalent of the Lingula flags of Wales. [Supplement to Acadian Geology (1860,) page 53; also Acad. Geol. 2nd ed., page 613.] Associated with these gold-bearing strata, along the Atlantic coast of Nova Scotia, occur fine grained gneisses, and mica-schists with andalusite and staurolite; besides other crystalline schists which are chloritic and dioritic, and contain crystallized epidote, magnetite and menaccanite. These two types of crystalline schists, (which, from their stratigraphical relations, as well as from their mineral condition, appear to be more ancient than the uncrystalline gold-bearing strata,) were in 1860, as now, regarded by me as the equivalents respectively of the White Mountain and Green Mountain series of the Appalachians; as will be seen by reference to Dr. Dawson's work just quoted. At that time, however, and for many years after, I held, in common with most American geologists, the opinion that these two groups of crystalline schists were altered rocks of a more recent date than that assigned to the auriferous series of Nova Scotia by Dr. Dawson; who was much perplexed by the difficulty of reconciling this view with his own. The difficulty is however at once removed when we admit, as I have maintained for the last two years, that both of these groups are pre-Cambrian in age [Amer. Jour. Sci. II, 1. 83; address to the Amer. Assoc. Adv Sei. August, 1871.]

A notice by Mr. Selwyn of some of these crystalline schists in

Nova Scotia will be found in the Report of the Geological Survey of Canada for 1870, [page 271]. He there remarks moreover the close lithological resemblances of the gold-bearing strata to the Harlech grits and Lingula-flags of North Wales, and announces the discovery among these strata at the Ovens goldmine in Lunenberg, Nova Scotia, of peculiar organic markings regarded by Mr. Billings as identical with the Eophyton Linnaanum, which is found in the Regio Fucoidarum, at the base of the Cambrian in Sweden. In the volume just quoted [page 269] will be found some notes by Mr. Billings on this fossil, which occurs also near St. John, New Brunswick, in strata supposed to underlie the Paradoxides beds. The same form is found in Conception Bay, in south-eastern Newfoundland, in strata regarded by Mr. Murray as higher than those with Paradoxides, and containing also two new species of Lingula, a Cruziana and several fucoids. Still more recently, Eophyton, accompanied by these same fucoids, has been found by Mr. Billings at St. Laurent, on the island of Orleans near Quebec, in strata hitherto referred by the Geological Survey, on stratigraphical grounds, to the Quebec group. The evidence adduced by Mr. Billings shows that this organic form, whatever its nature, belongs to a very low horizon in the Cambrian.

As regards the probable downward extension of these forms of ancient life, I cannot refrain from citing the recent language of Mr. Hicks. [Quar. Jour. Geol. Soc., May 1872, page 174.] After a comparative study of the Lower Cambrian fauna, including that of the Harlech and Menevian rocks in Wales, and the representatives of the latter in other regions, he adds:

'Though animal life was restricted to these few types, yet at this early period the representatives of the several orders do not show a very diminutive form, or a markedly imperfect state; nor is there an unusual number of blind species. The earliest known brachiopods are apparently as perfect as those which succeed them; and the trilobites are of the largest and best developed types. The fact also that trilobites had attained their maximum size at this period, and that forms were present representative of almost every stage in development, from the little Agnostus, with two rings to the thorax, and Microdiscus with four, to Erinnys with twenty-four; and blind genera along with those having the largest eyes; leads to the conclusion that for these several stages to have taken place numerous previous faunas

must have had an existence, and moreover, that even at this time in the history of our globe, an enormous period had elapsed since life first dawned upon it."

The facts insisted upon by Hicks do not appear to be inconsistent with the view that at this horizon the trilobites had already culminated. Such does not, however, appear to be the idea of Barrande, who in a recent learned essay upon the trilobitic fauna [1871] has drawn from its state of development at this early period, conclusions strongly opposed to the theory of derivation.

The strata holding the first fauna in south-eastern Newfoundland, rest unconformably, according to Mr. Murray, upon what he has called the Intermediate series; which is of great thickness, consists chiefly of crystalline rocks, and is supposed by him to represent the Huronian. He has however included in this intermediate series several thousand feet of sandstones and argillites which, near St. Johns in Newfoundland, are seen to be unconformably overlaid by the fossiliferous strata already noticed, and have yielded two species of organic forms, lately described by Mr. Billings. One of these is an Arenicolites, like the A. spiralis found in the Lower Cambrian beds of Sweden, and the other a patella-like shell, to which he has given the name of Aspidella Terranovica. [Amer. Jour. Science, III, iii, 223.] These, from their stratigraphical position, have been regarded as Huronian; but from the lithological description of Mr. Murray, the strata containing them appear to be unlike the great mass of the Huronian rocks of the region. Their occurrence in these strata, in either case, marks a downward extension of these forms of paleozoic life.

Mr. Billings has described from the rocks of the first fauna certain forms under the name of Archeocyathus, one of the species of which, according to Dr. Dawson, belonged to a calcareous chambered foraminiferal organism similar in its nature to much of the Stromatopora of the second, and closely related Coenostroma of the third fauna. All of these Dawson shows to have strong affinities to Eozoon, which is represented by E. Canadense of the Laurentian, and by similar forms in the newer crystalline schists of Hastings, Ontario, as well as by the E. Bavaricum of the upper crystalline schists of Bavaria. The succession of related foraminiferal organisms, is farther seen in the Devonian limestones of Michigan, where occur great masses