346 PROFESSOR GEIKIE ON THE 
employed to embrace all the deposits which were laid down between the close 
of the Silurian and the base of the Carboniferous system. In Canada and the 
north-eastern regions of the United States, a vast area, extending east and west 
for nearly 700 miles, and from the north of Michigan far into the middle states, 
was found to be occupied by a great thickness of strata (18,000 feet in some 
places), intermediate between the Silurian and Carboniferous formations. These 
have been identified with the European Devonian rocks, but have been claimed, 
from their thickness, their extent, and their varied organic contents, as a more 
ample, clear and typical development of the Devonian system than can be found 
in Europe. 
The first attempt to point out the distinction between the typical Old Red - 
Sandstone areas and those where rocks of the Devonshire type occurred was 
made by Mr Gopwin AUSTEN, in his very suggestive memoir “ On the possible 
Extension of the Coal-Measures beneath the South-Eastern part of England.” 
This paper appeared in 1855, and opened up a new era in the investigation of 
the history of the Old Red Sandstone.* The author boldly claimed for these red 
rocks the lacustrine origin which had been many years previously suggested by 
Dr JoHN FLEMING ; and he endeavoured to sketch out what seemed to have 
been the broad features of the physical geography of Western Europe during 
the Paleozoic periods. The influence of this paper may be traced in all the 
subsequent literature of the subject. The lacustrine character of the Old Red 
Sandstone, as distinguished from the marine strata known as “Devonian,” being 
enforced from fossil evidence by Professor Rupert Jones,t and from broad 
lithological considerations by Professor A. C. Ramsay, { has been very generally 
admitted by British geologists. The two terms have thus acquired a distinctive 
meaning, though both applied to rocks which the majority of geologists pro- 
bably still regard as geologically contemporaneous: Old Red Sandstone has in 
Britain been restricted to those deposits in which few or no unequivocally 
marine remains occur, but which by their lithological characters, and often by 
their organic remains indicate that they were laid down in inland areas of 
deposit ; while Devonian has been applied to the supposed marine equivalents 
of these lacustrine deposits. Although the alleged contemporaneity of these 
two groups of strata had, in England at least, been assumed rather than proved, 
it was received with such acceptance as to find a place in text-books and 
manuals as one of the recognised facts of the science. My lamented friend and 
colleague, the late Mr J. B. JuxKes, vigorously opposed the general assumption 
on this point. He contended that the ‘‘ Devonian ” rocks were younger than the 
Old Red Sandstone, and really formed the lowest division of the Carboniferous 
* “Quart. Journ. Geol. Soc.” vol. xii. p. 38. 
+ “Monograph on Fossil Estherie” (Paleontographical Society), p. 22. 
¢ “Quart. Journ. Geol. Soc.” vol. xxvii. (1871), p. 241. 

