Chap. XVIII.] 
DEVONIAN IN CANADA. 
437 
formation occurs, the magnesian and saliferous deposits of which, having been 
unfavourable to the support of life, have rendered the formation nearly des- 
titute of organic remains. In the eastern basin, however, this break is filled 
up by a series of rocks, on the Bay Chaleur and in the State of Maine, con- 
taining a fauna which has as yet been worked out only so far as to prove its 
absence from Western Canada and New York, and exhibiting many charac- 
teristic forms of the Wenlock and Ludlow fossils, such as Euomphalus rugo- 
sus, Bellerophon dilatatus, and Orthoceras filosum. At the summit of the Onon- 
daga formation, in the western basin, is the Water-limestone, characterized 
by Eurypterus, and above it the Lower Helderberg group. In the eastern basin 
the Gaspe limestones appear to form a great expansion of this group, and, 
together with the Bay-Chaleur limestones, are classed as Upper Silurian. 
" 2. Devonian Hocks. — The fauna of the lower Gaspe limestones still bears a re- 
semblance in many of its forms to that of the Ludlow rocks j but the upper pre- 
sent a considerable intermixture of Devonian species ; and Psilophyton princeps, 
a characteristic Devonian Land Plant, has been found towards the summit. This 
upper part, if not classed as Devonian, must be regarded as beds of passage. 
In accordance with this and the synchronism of de Verneuil, the Oriskany 
formation of New York is, in Canadian geology, assumed to be the base of the 
Devonian rocks. In the western basin this series is separated into several arena- 
ceous, calcareous, and argillaceous formations, each distinguished by its fossils. 
One of these formations in Western Canada, the Corniferous Limestone, is re- 
markable as the source, in that locality, of the great yield of petroleum, obtained 
from fissures which characterize a series of gentle anticlinals subordinate to the 
great Cincinnati undulation, which separates the Appalachian from the coal- 
fields of Michigan and Illinois. In the eastern basin the Devonian series is re- 
presented in Gaspe by seven thousand feet of sandstones. The organic remains 
discovered in these rocks are yet too few to authorize their separation into 
distinct members ; but while the lower part contains many fossils identical with 
those of the Oriskany formation, a species of Eensselasria, identical with or 
closely resembling R. ovoides which occurs in the limestone beneath, is met 
with high above the base of the sandstone series. This fact and the constancy 
in lithological characters of the latter make it probable that this lower portion, 
at least, of the sandstones is to be classed with the Oriskany Sandstone. From 
their base to their summit the Devonian rocks are profusely charged with com- 
minuted remains of Land Plants, in the recognized species of which, eight in 
number, there appears to be little difference throughout. These strata present 
analogies with the whole series of formations in New York, from the Marcellus 
Shales to the summit of the Chemung Sandstones, in all of which, according to 
Dr. Dawson, are found several of the species of Plants that occur in the Gaspe" 
sandstones. The sandstones resemble lithologically those of the Portage and 
Chemung group of New York; and it may hereafter be found that in this 
eastern part of the continent the Oriskany fauna, which occurs at their base, 
merges gradually into that of the Chemung deposit. In the Gaspe sandstones 
casts of shrinkage-cracks are very common, and root-beds, associated with 
Psilophyton, occur at many horizons ; and on one of the root-beds, near 
the base, reposes a very thin but regular seam of coal. Both the Gaspe sand- 
stones and the limestones beneath are marked by the presence of petroleum- 
springs, leading to the expectation that they may give out notable quantities 
of oil. 
" 3. Carboniferous Hocks. — Carboniferous rocks, as is well known, spread out 
