Morgan and Tollman — Occurrence of Bitumen. 371 



In short, this material can not be differentiated from ordinary 

 natural asphalt in any way. It would appear that the tar as it 

 exists in the fossil has not been completely bituminized, since 

 it apparently contains considerably more oxygen than bitu- 

 minous bodies generally possess. On heating to 150° C. the 

 transformation is completed and the resulting product is in all 

 respects a typical asphalt. The ready decomposition of the tar 

 and the entire change in its composition and nature after being 

 heated to 150° C. offer evidence that the specimen has never 

 been heated to this temperature previously. 



When the asphalt thus formed is heated to a dull red heat 

 more gas is liberated, doubtless due to "cracking" of the 

 high-boiling oils constituting it, and a residue resembling coke 

 is left. 



The Matrix. 



The matrix in which the egg is embedded varies from a 

 little less than half an inch to nearly an inch in thickness, and 

 consists of a fine-grained gray limestone, readily effervescing 

 when treated with dilute hydrochloric acid. A quantitative 

 analysis was deemed unnecessary. Qualitatively examined, it 

 gives slight tests for iron, aluminum, silicic and boric acids, 

 the relative amounts being in the order named. Magnesium 

 is present in larger quantity. No tests for sulphates, phos- 

 phates oi- chlorides were obtained. In short, the matrix seems 

 to be a limestone of considerable purity. It shows no geolog- 

 ical evidence of metamorphism whatever. 



In an indentation in one side of the limestone is a smal] 

 deposit of very fine hard clay, indicating that at some time 

 during its history the fossil embedded in its limestone capsule 

 has been buried under such conditions as to allow the forma- 

 tion of clay about it. 



On being fractured, especially when crushed in a mortar, 

 the limestone gives off the peculiar fetid odor supposed to be 

 due to the presence of organic matter. On dissolving in 

 hydrochloric acid an odor similar to that produced when iron 

 and zinc are treated with acids becomes apparent, and a slight 

 greasy scum is evident on the surface of the liquid when in a 

 test-tube. The intensity of these phenomena is not greater 

 than is observed frequently in limestones containing no appre- 

 ciable amounts of organic matter. 



In order to ascertain the nature and amounts of this organic 

 matter present, a piece of the matrix weighing about 10 grams 

 was extracted with petroleum ether to remove the tar filling 

 the pits and covering the inner surface. The piece was then 

 finely powdered and extracted again with boiling chloroform. 

 Upon evaporation, from 9*7380 grams of the matrix 0*006 gram 

 of tar similar to the other tarry material was obtained. 



