Bathyurus is a new genus, and as yet has no stratigraphical value in comparisons. Those which I described as Olenus have proved to be not true Oleni, and though much resembling that genus, are nevertheless distinct; I have proposed the name Barrandia and Bathynotus for the two forms.* These have yet no stratigraphical value, except so far as their relations to established genera may aid in that direction.

The genera Dikellocephalus and Menocephalus are of the Potsdam group; and so far the Quebec group is in parallelism with the Potsdam and Calciferous strata.

Of the other genera, we know Asaphus, Illanus and Ceraurus (=Cheirurus) in the Trenton limestone and Hudson River groups; Illanus and Ceraurus in the Upper Silurian strata of Niagara age, or the third fauna of Barrande; while Ceraurus occurs also in the Devonian of Europe. Amphion is known in the second fauna in Europe, and, doubtfully in the first.

Ceraurus does not occur in this country, so far as I know, above the Niagara group, though known in the Devonian rocks of Europe.

The following tabular arrangement of the genera found in the Quebec group will serve to express more distinctly the relations of the crustacean fauna of these rocks.

The letters at the head of the columns have the same references as those used in the communication of Sir William Logan.

• Thirteenth Annual Report of the Regents of the University of N. Y., on the State Cabinet of Natural History, Albany, December, 1860.

In this table we find, of previously recognized trilobites of the primordial fauna, two genera and five species; of previously known genera of the second and third faunæ, four genera and eight species; two genera before known in the Potsdam sandstone and seven species; and of Agnostus, which is of the first and second fauna, two species; and one new genus with nine species.

These are certainly very curious results; and a modification of our views is still required to allow four genera and eight species, (or leaving out Amphion) three genera and six species of the trilobites of the second fauna to be associated with two genera and five species of trilobites of the primordial fauna, and yet regard the rock as of primordial origin.

The brachiopodous genera, Lingula, Discina, Orthis, Leptana and Strophomena, have a great vertical range, and are known in the Lower and Upper Silurian, and most of them in the Devonian; while Camerella so far as known is a Lower Silurian form of the second fauna (perhaps also in a lower position).

Of the gasteropoda, Maclurea and Ophileta are restricted to Lower Silurian rocks, but occur mainly in the second fauna. The other genera occur likewise in the second fauna and in the Upper Silurian rocks as well as some of them in Devonian. The same is true of the cephalopoda enumerated.

Tetradium is known in the second fauna of the Lower Silurian

rocks, and in the upper part of the Hudson River group at the west. Dictyonema is a genus known from Lower Silurian to Devonian strata.

Graptolithus proper extends to the Clinton group of New York; and the same is true of Reteograptus. Tamnograptus occurs in the rocks of the Hudson River group near Albany, and in the Quebec rocks. Phyllograptus and Retiolites are known in the Quebec rocks only; while the typical form of Dendrograptus occurs in the Potsdam sandstone, and, likewise, in three other species, in the Quebec rocks.

We find, therefore, in the other genera, except trilobites, very little satisfactory evidence on which to rely in the present state of our knowledge, for determining the position of these strata.

In the present discussion, it appears to me necessary to go further, and to inquire in what manner we have obtained our present ideas of a primordial, or of any successive fauna. I hold that in the study of the fossils themselves there were no means of such determination prior to the knowledge of the stratigraphical relations of the rocks in which the remains are inclosed. There can be no scientific or systematic paleontology without a stratigraphical basis. Wisely then, and independently of theories, or of observations and conclusions elsewhere, geologists in this country had gone on with their investigations of structural geology. The grand system of the Professors W. B. and H. D. Rogers had been. wrought out not only for Pennsylvania and Virginia but for the whole Appalachian chain; and the results were shown in numeous carefully worked sections. In 1843, '44 and '45 I had myself several times crossed from the Hudson River to the Green Mountains, and found little of importance to conflict with the views expressed by the Professors Rogers in regard to the chain farther south, except in reference to the sandstone of Burlington, and one or two other points, which I then regarded as of minor importance.

Sir William Logan had been working in the investigations of the geology of Canada; and better work in physical geology has never been done in any country.

This then was the condition of American geology, and investigators concurred, with little exception, in the sequence based on physical investigations. As I have before said, our earliest determinations of the successive fauna depend upon the previous stratigraphical determinations. This I think is acknowledged

by Mr. Barrande himself, when he presents to us, as a preliminary work, a section across the centre of Bohemia. With all willingness to accept Mr. Barrande's determination, fortified and sustained as it is by the exhibition of his magnificent work upon the trilobites of these strata, we had not yet the means of parallelizing our own formations with those of Bohemia by the fauna there known. The nearest approach to the type of primordial trilobites was found in those of the Potsdam sandstone of the northwest, described by Dr. D. D. Owen; but none of these had been generically identified with Bohemian forms; and the prevailing opinion, sanctioned as I have understood by Mr. Barrande, was that the primordial fauna had not been discovered in this country, until the re-discovery of the Paradoxides Harlani, at Braintree, Mass. The fragmentary fossils published in vol. 1, Palæontology of New York, and similar forms of the so-called Taconic system, were justly regarded as insufficient to warrant any conclusions. It then became a question for paleontologists to decide, whether determinations founded on a physical section in a disturbed and difficult region of comparatively small extent, were to be regarded as paramount to determinations founded on examinations, like those of the Professors Rogers, extending over a distance in the line of strike of five or six hundred miles; and those of Sir William Logan over nearly as great an extent from Vermont to Gaspé.

It is not possible for me, at this moment, to give the time necessary for a full discussion of this important subject. In presenting these few facts in this form, I am far from doing it in the spirit of cavilling, or as an expression of distrust in any direction. It is plain that the case is not met in Mr. Barrande's plan of successive trilobitic faunæ; and the facts yet brought out do not serve to clear up the difficulty. It is evident that there is an important and perplexing question to be determined,-one that demands all the wisdom and sagacity of the most earnest inquirers, and one which calls for the application of all our knowledge in stratigraphical geology and in paleontology;-one in which coöperation, good will and forbearance are required from every one, to harmonize the conflicting facts as they are now presented. The occurrence of so many types of the second fauna in the rocks at Point Levi, associated with a smaller number of estab

• The glabella of small trilobites undistinguishable from Conocephalus occur in the Potsdam sandstone near Trempaleau, Wisconsin, on the Mississippi river.

lished primordial types, offers us the alternative of regarding these strata as of the second stage, with the reappearance of primordial types in that era, or of bringing into the primordial zone several genera heretofore regarded as beginning their existence in the second stage: in either case, so far as now appears, conflcting with the scheme of Mr. Barrande in reference to the successive fauna of trilobites as established in Bohemia and the rest of Europe.

For myself I can say, that no previously expressed opinion, nor any "artificial combinations of stratigraphy previously adopted" by me, shall prevent me from meeting the question fairly and frankly. I have not sought a controversy on this point, but it is quite time that we should all agree that there is something of high interest and importance to be determined in regard to the limitation of the successive fauna of our older palæozoic rocks.

I am, yours, &c.,

JAMES HALL.

Albany, N.Y., Jan. 23, 1861.

ARTICLE VIII.-Catalogue of Plants collected in the Counties of Argenteuil and Ottawa, in 1858. By W. S. M. D'URBAN. The following list of Plants contains 362 species, all of which were collected strictly within the Laurentian district, many introduced species growing on the fossiliferous rocks in the immediate neighbourhood of the town of Grenville, being omitted. A large portion were determined by myself on the spot with the aid of Dr. Asa Gray's admirable "Manual of the Botany of the Northern United States," which was my almost constant companion during the five months I spent in the district, but I have to acknowledge my obligations to Mr. G. Barnston, who kindly assisted me in naming some phenogamous species; to Col. Munro, C. B., 39th Regt., who most obligingly determined the whole of the sedges and grasses; to Mr. D. Allan Poe, who examined the cryptogams, and named all the mosses, some of which he submitted to the eminent bryologist, Mr. James of Philadelphia; and lastly to Dr. Dawson for allowing me unlimited access for purposes of reference to the Holmes herbarium deposited in McGill College.

Many of the specimens collected were so small and depauperated in form, from the poverty and scantiness of the soil that I found it.