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XVI.—On the Old Red Sandstone of Western Europe. By 
Professor GEIKI£E, LL.D., F.R.S. (Plate XXII.) 
( Read 1st April 1878.) 
PARL A. 
HIsToRIcAL INTRODUCTION. 
In the early part of the present century, when stratigraphical geology, start- 
ing from the clear succession of Secondary rocks of England, was groping its 
way among the older formations in this country and abroad, the Old Red Sand- 
stone occupied a somewhat indeterminate position. The series of deposits 
comprised under that name had been recognised chiefly in the British Islands, 
hardly at all on the opposite mainland of Europe. By most geologists they 
were classed as a subordinate and inconstant portion of the Carboniferous 
system, while by some they were placed rather at the top of the yet unexplored 
“Transition” or “ Greywacke” series. MurcuHison first claimed for them the 
dignity and importance of a distinct system.* On the whole, they had yielded 
comparatively few organic remains ; they consequently seemed to lie as a thick 
red barren zone between the richly fossiliferous Silurian deposits below them 
and the equally fossiliferous Carboniferous limestone above. By degrees, how- 
ever, as they brought forth a rich harvest of new and strange ichthyolites, they 
indicated their own right to recognition, and when they were found covering a 
vast space in Russia with many of the same types of fish as they had yielded 
in Britain, their claim to rank as a distinct and independent system was no 
longer contested. 
In the year 1839 SEepeGwick and MurcuHIson, adopting a suggestion of 
_ Lonspate’s, established the Devonian system, and showed that it extended over 
_ a considerable area in Central Europe, with everywhere the same characteristic 
_™marine fauna. The validity of this step in the classification of the geological 
record was ere long universally admitted. The new term “ Devonian,” as a 
convenient euphonious adjective, and one readily transferable into other 
_ languages, passed at once into general use; while the earlier name of “ Old Red 
Sandstone,” never much in vogue out of this country, fell somewhat into dis- 
use. Even the Old Red Sandstone of the original and typical Welsh and Scottish 
areas, from which not a single shell or trilobite like those of Devonshire had 
been obtained, was now often spoken of as “ Devonian,”—that term being 
* In his “ Silurian System ”( 1839). 
VOL. XXVIII. PART II. 4x 
