A MONOGRAPH 



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BRITISH DEVONIAN BRACHIOPODA. 



PRELIMINARY REMARKS. 



Between the Upper Silurian and Lower Carboniferous series of deposits there exists a 

 very extensive formation, to which the designation of Old Red Sandstone or Devonian 

 System has been given. This formation, composed of numerous alternations of sand- 

 stone (chiefly red), shale, slate, and limestone, is largely developed in several of the 

 counties of Great Britian, and especially in those of Devonshire and Cornwall, whence 

 most of the examples of Brachiopoda figured in this monograph have been derived. 



In the present monograph on the British Devonian Brachiopoda, I purpose to 

 commence with illustrating their many and varied forms, and to reserve, until a future 

 occasion, any remarks upon their local and general distribution. Before, however, 

 entering into these details, I would direct attention to the following observations of 

 Professor Ramsay, given in his Anniversary Address to the Geological Society of London, 

 on the 20th of February, 1863, as being the most recent views published upon the 

 subject. 



"Devonian Bocks. — Excepting that they are arranged in a given order of superposition, 

 there is little to be said respecting the relation of the fossils to the stratigraphical relations 

 of the Devonian rocks of the south-west of England. When, many years ago, that area 

 was mapped, extreme analyses in geological surveying had scarcely been introduced ; and 

 in that country, consisting so largely of granite and gneiss, contorted greywacke and 

 limestone, no one attempted on maps to split up the Devonian series into distinct sub- 



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