494 NOTE ON THE ORIGIN OF " KEROSENE SHALE," 



The author has been unable to ^et access to the two last-men- 

 tioned works, but these references may perhaps be of use to others. 



The many points of resemblance between coorongite and kero- 

 sene shale may serve as an excuse for the author having intro- 

 duced so lengthy a quotation as to its nature and probable origin. 

 So long, however, as these remain a mystery, their exact bearing, 

 if any, on the origin of kerosene shale, must remain in abeyance. 



Arguments against Drift Timber Theory. — (1) Had kerosene 

 shale been formed from rafts of resinous trees, which became 

 macerated at the spots where we now find kerosene shale, it is 

 unlikely that the maceration should in every case have been so 

 thorough and complete as not to leave a vestige of woody struc- 

 ture behind. At Trinidad, for instance, as already related, the 

 wood in the asphaltic deposits exhibits every gradation of change 

 from the ligneous into the bitumenous state, so that if the w^hole 

 deposit were buried under thick sediments for a long geological 

 period until it became completely fossilized, and were afterwards 

 re-exposed by denudation, there would be ample proof of the 

 formation of bitumen from woody matter in the fragments of the 

 undecomposed and partially decomposed woody material in the 

 rocks associated with the bitumen, and the latter would also con- 

 tain pseudomorphs in bitumen after the original individual frag- 

 ments of wood. In the case, however, of the kerosene shale 

 seams of this colony fragments of fossil wood are rarely found in 

 the strata immediately associated with the kerosene shale seams. 



(2) It is difficult to understand how Glossopteris leaves could 

 have become so delicately interleaved with the laminae of the 

 kerosene shale, or the Vertebraria stems have maintained their 

 erect position in the kerosene shale, supposing it to have originated 

 from a mass of drift wood. Such leaves would in the case sup- 

 posed have been chiefly restricted to the top of the mass, and 

 would not have been evenly distributed through it, as they are 

 now found. 



(3) The resins in such trees, during such supposed maceration, 

 would be liable to separate out in places into small irregular 



