S. Ff. Peckham—The Origin of Bitumens. — 109 
form the bed of the ocean. The narrow plain on which Santa ~ 
Barbara stands, lying between the Santa Ifez mountains and 
the sea, consists of Pliocene and Quaternary sands and gravels 
resting upon the eroded shales. East of the Rincon and 
ount Hoar, the table-lands lying in the trough of the anticli- 
nal gradually ascend until at the Sespé the sandstone caps th 
high -mountain to the eastward. This range, occasionally 
the Santa Clara River near the Solidad Pass, where it becomes 
merged in the San Rafael range. Between Point Conception 
and Point Rincon, where a stratum of sand occurs saturated 
with maltha, that substance has arisen and floated on the sea, 
attracting the notice of travelers ever since that coast was. 
nown to Europeans. At Point Rincon, where the anticlinal 
recedes from the coast, maltha rises and saturates the Quater- 
nary sands. As the ascending plateau passes farther inland 
we find a line of outcrop of the bituminous strata on the east 
and west sides of the basin in the line of hills east of Mount 
Hoar and in the Santa Ifiez mountains. East of the San 
Buena Ventura River, the local synclinal fold in the shale 
forming the Azufre mountain gives four lines of bituminous. 
outcrop. In the cafions of the Sespé, wherever the bituminous 
strata have been reached by erosion, tar springs and asphalt 
beds are the result. The deeply-eroded narrow valleys which 
cover the country east of Santa Barbara and south of the Coast 
Range present in the distance of a few miles the greatest litho- 
logical variations, and expose the bituminous strata under the 
greatest diversity of conditions. For this reason we meet here 
every possible form of bitumen in every possible degree of 
admixture, with soil and organic remains. 
The second class of bitumens includes the petroleums of 
New York, Pennsylvania, Ohio and West Virginia. These 
with a considerable quantity of marsh gas, and very volatile 
liquids that cannot be condensed except at low temperatures. — 
