266 The Founders of Geology LECT. 



the stratigraphy of the older stratified rocks. For two 

 years they continued in complete uncertainty as to the 

 solution of the problem. But at last after the examination 

 of innumerable specimens, endless discussion, and inter- 

 minable correspondence, they came to adopt Lonsdale's 

 views. They saw that the abundantly fossiliferous rocks 

 of South Devon contained, in their lower members, fossils 

 that reminded them of Silurian types, while in their 

 upper members, they yielded species that were common 

 also to the Carboniferous Limestone. The two geologists 

 therefore recognized in these rocks an intermediate series 

 of strata, containing a fauna which must have flourished 

 between the Silurian and the Carboniferous periods. That 

 fauna was not represented in the Old Eed Sandstone, 

 which, with its traces of land -plants and remains of 

 ganoid fishes, appeared to have been accumulated under 

 other geographical conditions. To distinguish the series 

 of rocks containing this well-marked facies of marine 

 organisms, they chose the name "Devonian," from the 

 county where they were originally studied and where 

 their true position was first ascertained. 1 The authors 

 claimed that the establishment of the Devonian system 

 was "undoubtedly the greatest change which has ever 

 been attempted at one time in the classification of British 

 rocks." But it was far more than that. It was the 

 determination of a new geological series of world-wide 

 significance, the unfolding of a new chapter in the geo- 

 logical annals of our globe. Soon after Sedgwick and 

 Murchison had finally announced to the Geological 

 Society their reform of the geology of Devonshire, they 



1 Trans. Geol Soc., 2nd ser. vol. v. pp. 688, 701 (April 1839). 



