442 REPORT OF NATIONAL MUSEUM, 1899. 



and stated to be fluidal and at a high temperature in the center. 1 This 

 is quite erroneous and misleading. 



The crude material has the following composition and physical 

 characteristics : 2 



Specific gravity, 1.28; hardness at 70 F., 2.5 to 3 of Dana's scale; 

 color, chocolate brown; composition: 



Bitumen 39. 83 



Earthy matter 33. 99 



Vegetable matter. 9. 31 



Water 16.87 



100. 00 



In western Kentucky asphalt exudes from the ground in the form 

 of "tar springs," and occurs also disseminated through sandstones and 

 limestones of sub-Carboniferous age. (Specimen No. 63345, U.S.N.M.) 

 Frequently, as in the dolomite underlying Chicago, Illinois, the bitu- 

 minous matter is so diffused throughout the rock as to give it on expo- 

 sure a brownish-black appearance, and cause it to exhale an odor 

 of petroleum appreciable for some distance. (Specimen No. 62T89, 

 U.S.N.M.) In the Dead Sea bituminous masses of considerable size 

 have in times past risen like islands to the surface of the water and 

 furnished thus the material used by the ancients in pitching the walls 

 of buildings and rendering vessels water-tight. The ancient name of 

 this body of water was Lake Asphaltites, and from it our word asphalt 

 is derived. These illustrations are sufficient to indicate the numerous 

 conditions under which the substance occurs. The material is world- 

 wide in its geographic distribution and equally cosmopolitan in its 

 geological range, being found in gneissic rocks of presumably Archaean 

 age in Sweden, and in rocks of all intermediate horizons down to late 

 Tertiary. 



Some 10 miles east of the city of Habana, Cuba, is a deposit of 

 asphalt described 3 as occupying an irregular branching fissure in a 

 soft clay rock, with eruptive rocks, diorites, and euphotides in the near 

 vicinity. The asphalt, described as "Coal" in the paper referred to, 

 lies in parallel horizontal layers of from 1 to 4 inches in thickness 

 across the vein, the laminas being somewhat deflected near the walls, 

 as if pressed by the sides or walls. The deposit is regarded as having 

 originated as an open fissure terminating upward in a wedge-like 

 form and into which was subsequently injected from below the carbo- 

 naceous matter. The asphalt itself was described as of a jet-black 



J See Mineral Resources of the United States, 1883-84, p. 937; also Dana's System 

 of Mineralogy, 1892, p. 1018; and especially S. F. Peckham's paper on the Pitch 

 Lake of Trinidad, American Journal of Science, July, 1895, p. 33. x 



2 Transactions of the American Institute of Mining Engineers, XVII, 1889, p. 363. 



3 London and Edinburgh Philosophical Magazine and Journal of Science, X, 1837, 

 p. 161. 



