Geological Society. 485 
boniferous and Silurian systems, were familiar. It was soon per- 
ceived, that while some of the South Devonshire fossils approached 
to those of the carboniferous strata, and others to those of Siluria, 
there were still many species which could not be assigned to either 
system; the whole, taken together, exhibiting a peculiar and inter- 
mediate paleontological character. Mr. Lonsdale therefore sug- 
gested, that the difficulties which had perplexed this inquiry could 
be removed by regarding the limestones of South Devon as subor- 
dinate to slaty rocks, which represent the old red sandstones of Here- 
ford, Wales, Scotland, and Ireland,—their true place in the series of 
Devonshire being intermediate between the culmiferous basin of 
North Devon, and the Silurian strata,—if the latter exist in that 
county. 
The value of this suggestion was not at first appreciated; but 
after the lapse of more than a year, Mr. Lonsdale’s views were 
adopted (March 1839) by Messrs. Sedgwick and Murchison*, who 
soon afterwards applied this new arrangement not only to the groups 
of Devonshire originally under review, but with a boldness which 
does credit to their sagacity, extended it to the whole of the slaty 
and calciferous strata of Cornwall, till then known only as grau- 
wacke, clay-slate, or killas; assigning to those strata, likewise, the 
date of the old red sandstone, and resting this determination entirely 
on the character of the fossils. This change—the greatest ever 
made at one time in the classification of our English formations— 
was announced in a memoir read before the Geological Society in 
April 1839; the authors then also proposing for the whole series 
(including both the old red sandstones of Herefordshire, and the 
fossiliferous slates and limestones of South Devon and Cornwall, ) the 
new name of “the Devonian system,” and expressing their belief, 
that many of the groups hitherto called grauwacke, in other parts 
of the British Islands and on the continent, would ere long be re- 
ferred to the same geological epoch. 
The proposed alteration, therefore, will terminate the perplexity 
hitherto arising from the circumstance, that the o/d red sandstone of 
Werner has been frequently confounded with the new red sandstone 
formation of English geologists. It also explains the cause of the 
English old red sandstone having been rarely recognised on the 
continent :—for if the Devonian slates afford the nermal type of 
* Itis to be observed here, that Mr. Murchison, having previously shown 
that the fossils of the Silurian era are distinct from those of the carboni- 
ferous period, had also pointed out ‘‘ the vast accumulations” (in which 
few fossils had at that time been discovered) ‘‘ then known to separate the 
. two systems.”” He mentions especially, that “the fishes of the old red 
sandstone—entirely distinct as to form and species—are as unlike those 
of the Silurian system, as they are to those of the overlying carboniferous 
system:” adding, ‘‘ that he has no doubt, although at present unprovided 
with geological links to connect the whole series, that such proofs will 
be hereafter discovered, and that we shall then-see in them as perfect evi- 
dence of a transition between the old red sandstone and carboniferous 
rocks, as we now trace from the Cambrian, through the Silurian, into the 
old red system.”—See Silurian System, p. 585, line 22, et seq. 
