CHAPTEE XIX. 



THE DEVONIAN GROUP. 



Old Red Sandstone, or Devonian System, of English Authors ; Gres Rouge 

 Intermediate, of French ; Grauwacken-Gebilde, of German Authors. 



MUSEUMS : British Museum ; Geological Society ; various Collections in 

 Scotland. 



AUTHORS : Miller, Murchison, Sedgwick, Boue, De Verneuil, Agassiz. 

 CHARACTERISTICS : A Marine deposit, chiefly remarkable for its Fossil Fishes. 



THIS group affords a striking illustration of the progressive 

 nature of geological inquiry. Up to a recent period, the old 

 red sandstone was regarded as a subordinate member of the 

 carboniferous series, and from its supposed paucity of fossils 

 was usually passed over in silence and neglect. 



Owing, however, to the researches of modern geologists, 

 and in particular of that distinguished observer by whom the 

 Silurian rocks have been raised to the rank of a distinct 

 system, the Devonian has been found to form an important 

 group in the palaeozoic series, characterised by a well- 

 developed and distinctly denned fauna. 



The name is derived from the circumstance of this group 

 being extensively developed in Devonshire. A triple 

 subdivision has been proposed by Sir R Murchison.* 



I. QUARTZOSE CONGLOMERATES AND SANDSTONE. 



(a). The upper beds consist of quartzose grits, with a 

 slight calcareous cement, or pink and reddish quartzose con- 

 glomer'ates, passing 



(b). Downwards into chocolate, brown, and reddish, coarse- 



* Silurian System, page 170, et seq. 



