DEVONIAN STRATA IN THE UNITED STATES. 455 
The calcareous and the arenaceous rocks of Russia above al¬ 
luded to alternate in such a manner as to leave no doubt of 
their having been depos- Fig. 523 . 
ited in different parts of 
the same great period. 
Devonian Strata in the 
United States and Canada, 
— Between the Carbonif¬ 
erous and Silurian strata 
there intervenes, in the 
United States and Canada, 
a great series of formations 
referable to the Devonian 
group, comprising some 
strata of marine origin 
abounding in shells and 
corals, and others of shal¬ 
low - water and littoral 
origin in which terrestrial 
plants abound. The fos¬ 
sils, both of the deep and 
shallow water strata, are 
very analogous to those 
of Europe, the species be¬ 
ing in some cases the 
same. In Eastern Canada 
Sir W. Logan has pointed 
out that in the peninsula 
of Gaspe, south of the es¬ 
tuary of St. Lawrence, a 
mass of sandstone, con¬ 
glomerate, and shale refer¬ 
able to this j)eriod occurs, 
rich in vegetable remains, 
together with some fish- 
spines. Far down in the 
sandstones of Gaspe, Dr. 
Dawson found, in 1869, an 
pntirp <inPpiTnPn flip o'p Psilophyton primceps, Dawson, Qnart. Geol. 
enine specimen Ot tne ge- Joum., vol. xv., ises; and Canada Survey, 
Cephalaspis, a form so Species characteristic of the whole 
1 Devonian series in North America. 
characteristic, as we have . 4 . . , • t. o. 4 . i • 
, 1 01 1 a. Fruit; natural size. h. Stem; natural size, 
already seen, of the bcotch c. Scalariform tissue of the axis highly mag- 
Lower Old Red Sand- 
stone. Some of the sandstones are rippled-marked, and to¬ 
wards the upper part of the whole series a thin seam of coal 
has been observed, measuring, together with some associated 
