of Bitumens, and of Bituminous Shales. 165 
bitumen, and left a nearly white calcareous residue, free from 
carbonaceous matter. Such a rock as this is rightly designated 
in character, are probably but altered portions of the same bitu- 
k, 
m the Grand Manitoulin Island, are filled with brown asphalt, 
Which melts and exudes by a gentle heat, and is completely sol- 
uble in benzole. It forms from 7-4 to 8°8 per cent of the rock. 
n altered form of petroleum is also found near the oil wells of 
Enniskillen, where the product of tbe natural oil springs appears 
Matériaux de Construction aU Exposition de 1855, page 390. On page 
eal the same volume Delesse has deseri iar brownish-black compact 
line eo rock, from Promina in Austria, which consists of 59°0 parts of a cry: t 
Matter cone 9°0 parts of clay, and 82°0 ee of a_ brownish-black combustible 
~ esse, designated as a lignite, from whieh hor d ish 
. lusibility - It would seem he, a hitherto undescribed matter intermediate be- 
ite and asphalt. 
“Your. Sc1.—Szconp Senms, Vou. XXXV, No. 104.—Maxcn, 1863, 
22 
