Morgan and Tallmon — Occurrence of Bitumen. 375 



5 or 6 grams of residue from the contents of an egg of the 

 size of the present specimen is not, therefore, unduly large. 



It is difficult to estimate closely the amount of tar present 

 in the fossil because of its varying distribution. The total 

 quantity of bituminous matter could not have been more than 

 3 grams and was probably much nearer 2 grams. This 

 amount might well have been derived from the fat alone. 

 The absence of nitrogen in the bitumen may possible be 

 accounted for by the suggestion that the easily decomposable 

 protein may have entirely disappeared, while the more stable 

 fatty constituents may alone have become bituminized. 



The derivation of the tar from the original contents of the 

 egg is, then, entirely possible, and from what is known of the 

 process of bituminization its origin from such a source, under 

 the conditions to which it has doubtless been subjected, is not 

 in the least improbable. In the absence of any evidence to 

 the contrary, therefore, since extraneous sources have been 

 shown to be highly improbable, no reasonable ground seems 

 to exist for doubting that the tar now present in the fossil has 

 been derived from the natural contents of the egg. 



Bearing. 



After more than seventy years of painstaking investigation 

 from the purely scientific as well as technical sides, the matter 

 of the origin of bitumens is still an open question in many 

 respects. Three entirely distinct theories have been before the 

 world for years, ascribing their origin to three separate and 

 distinct sources. The laboratory investigations of Moissan, 

 especially for the theory of inorganic origin, and of Warren, 

 Daubree, Engler, Day and Sadtler for the organic side, have 

 made it apparent that the results of experimentation support 

 any theory and that artificial production indicates only the 

 possibilities and not necessarily the realities as to the origin of 

 bitumens. 



Furthermore, every case of artificial production of bituminous 

 matter has required a temperature much beyond the ordinary, 

 a condition which an examination of natural deposits seems to 

 render exceedingly improbable. "What geologists would be 

 glad to find in Nature," says Professor Orton,"* "as matching 

 to and harmonizing with the facts with which they are obliged 

 to reckon, would be a process in which the products of the 

 organic world are transformed into mineral oil at ordinary tem- 

 peratures with complete consumption of the substances acted 

 upon so that no carbon residue would be left behind. They 

 would also expect the transformation to be accomplished while 



*Bull. Geol. Soc. Am., 9-90 (1898). 



