7 
SUCCESSION OF PALEOZOIC DEPOSITS IN RUSSIA, 
have ourselves made in Scandinavia, European Russia and the Ural Mountains. 
This appeal, we have no hesitation in saying, has unequivocally sustained the 
conviction, that whilst the Lower Silurian is there the lowest fossiliferous type, 
it is also the base of a series composed of overlying formations, very distinctly 
referable to the Upper Silurian, Devonian and Carboniferous groups. We may, 
indeed, assert, that as the proofs of these natural divisions there extend over a very 
large portion of the earth, and in a completely unaltered state, so are they still 
more clear than those offered by any one region hitherto examined. In the north 
of England, for example, the palaeozoic succession is broken ; for the Old Red 
Sandstone is a mere conglomerate without fossils, and although the Upper Silurian 
rocks are copiously developed in a slaty and subcrystalline form (the beds con- 
taining many fossils), the place of the Lower Silurian, with the exception of the 
uppermost strata, is occupied by great masses of chloritic schist, alternating with 
countless, contemporaneous ribs of porphyry, as well as with trappaean conglome- 
rates and slaty beds derived mechanically from materials of igneous origin 1 . In 
Scotland, where the old red formation is copiously spread out in sandstone, shale 
and conglomerates, and contains many ichthyolites, it is void of mollusks, and the 
schistose rocks which succeed to it have been as yet but obscurely characterized 
as Silurian by their organic remains, though certain bands with trilobites, corals 
and other fossils have been observed in the Galloway hills, which, overlying the 
older grauwacke, must, we think, belong to the Upper Silurian group 2 . Even in 
the typical Silurian region, where the stratigraphical order and succession are so 
unequivocal, the Old Red Sandstone contains, as before said, no shells ; and in 
Devonshire, where shells abound in the same system, no fishes have been seen and 
a few broken portions only of Silurian rocks have recently been recognised in Corn- 
wall 3 . Again, in most of these tracts, as well as in the Rhenish provinces, the 
1 See Professor Sedgwick’s memoir read before the Geol. Soe. of London, March 1845. 
2 See Professor Sedgwick’s memoir, Proc. Geol. Soc. vol. iii. p. 553. Some years ago Graptolites 
were, indeed, discovered in the schists of Wigtonshire by Mr. John Carrick Moore (Proc. Geol. Soc. 
vol. iii. p. 277), and even whilst we write, we have seen Orthoceratites from the black schists of St. Mary’s 
on the southern shores of Kircudbright, recently found there by the Earl of Selkirk, which are unques- 
tionable Upper Silurian forms. 
3 By the discoveries of Mr. C. W. Peach, shells and fishes apparently belonging to the uppermost beds 
of the Silurian system have been recognised between Looe and Fowey in Cornwall. Air. Peach indeed 
believes, that several fossils of other and lower formations of the Silurian system also occur in Cornwall • 
but the very imperfect condition of these bodies and the absence of stratigraphical order have hitherto 
prevented very decisive identifications. (See 31st Report of the Royal Geol. Soc. of Cornwall.) 
