E. G. Case— Amphibian Fauna at Linton^ Ohio. 131 



2. The evidence from the presence of cannel coal. 



Without going into the history of the discussion of the origin 

 of the various kinds of coal, it is sufficient to state tliat it is now 

 the generally accepted opinion that boghead, boghead-cannel, 

 and cannel coals have been forniied bj the accumulation of 

 algae, spore exines, bits of resin, and other light, wind-blown 

 materials which have grown in place in open water or have 

 accumulated on the surface of open pools. Details of the dis- 

 cussion and the general conclusions may easily be found by 

 following the references s^iven by David White in his treat- 

 ment of the origin of coal.^ It is also of interest to note that 

 the theory of the origin of cannel coal recognizes the necessity, 

 or at least the advantage, of the presence of decomposing ani- 

 mal matter in its formation. 



Accepting as a working basis that the stratigraphy and the 

 presence of the cannel coal demonstrate the presence of an 

 open pool in the vicinity of Linton, we may turn to the history 

 of this pool and the other factors which influenced the develop- 

 ment of the fauna. 



East of Linton the Lower Freeport Coal lies directly upon 

 the sandstone, but at Linton the section of the old Diamond 

 Coal Mine shows several feet of hre clay beneath it. Fire clay 

 is the result of the action of peaty waters, containing much 

 CO2 in solution upon an underlying soil. It is apparent that 

 succeeding the long period of submergence during which the 

 Lower Freeport Sandstone was formed there was a slight ele- 

 vation, but a local depression in the vicinity of Linton retained 

 a considerable body of fresh water in which accumulated the 

 sediments of the adjacent land. The water at the edges of 

 this pool was not deep enough to prevent the rapid develop- 

 ment of an abundant flora. The roots penetrated the soil and 

 the decomposition of the vegetal material furnished an abund- 

 ance, of CO2 which deprived the soil of its alkalis, alkaline 

 earths, and iron, reducing it to a tire clay. The bordering veg- 

 etation did not for a long time spread out over the surface of 

 the pool in tiie middle of the swamp and during this interval 

 there accumulated the material of the cannel coal and the 

 amphibian and fish fauna developed large numbers both of indi- 

 viduals and species. The presence of a single form which 

 must be placed with the reptilia indicates either a land at no 

 great distance, from which the body of the animal was trans- 

 ported after death, or an aquatic habit for the reptile. 



The physiographic environment of the fauna. 



I. C. White has insisted upon the fact that though the beds 



of the Allegheny series are subject to frequent changes in the 



* White, David, The Origin of Coal, Bull. 38, Department of the Interior, 

 Bureau of Mines, page 198, 1918. 



