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at Middleton, with Lingulse ; at the top of the series in 

 Lancashire and Derbyshire, with Mytili." 



The highest class of vertebrate animals whose remains 

 are found in the Coal Measures, is that of Fishes. On 

 the continent between Coblentz and Cologne, there is what 

 is termed the brown Coal formation or paper Coal, (a more 

 recent deposit, however, than the Coal Field,) in which are 

 found besides Fishes, Batrachian Reptiles, as the frog, &c. 

 Mr. Lyell states that an entire jaw and other bones of an 

 extinct mammiferous quadruped, the Anthracotherium, have 

 been found in the Coal beds of Cadibone, the bone itself 

 being changed into a kind of Coal. In these beds, however, 

 although comprising Carbonaceous shales, and several seams 

 of Coal from two to six feet in thickness, no shells have 

 been discovered, nor impressions of plants of which the 

 species can be determined. In the Yorkshire Coal Field, 

 though we cannot lay claim to any quadrupedal or reptilian 

 remains, still we have the fishes of various genera and species, 

 which are of great importance to the Geologist. " Fishes," 

 observes Agassiz, " being more than all other animals most 

 intimately connected with the incidents of the water, and their 

 organization being besides very high up, they are better cal- 

 culated than any other class to give us clear ideas regarding 

 the changes which have been going on in such vast seas as 

 have formerly covered over the earth. We shall be enabled 

 to determine if a fish has lived in rivers, in lakes, or in 

 ponds ; in the high sea or upon its shores ; if it was an 

 inhabitant of the surface of the water, or of its great 

 depths ; which indications, more or less valuable, will aid us 

 in determining corresponding circumstances with regard to 

 the formation of rocks." To enable the Geologist, however, 

 to bring so successfully Zoological identity to his assistance, 

 he must enter into the labours of the Comparative Anatomist, 

 and Zoologist, and study the minute structure and characters 



