NOTICES OF MEMOIRS. 
59 
NOTICES AND ABSTRACTS OF SCIENTIFIC 
MEMOIRS. 
Petroleum and Oil -Fields. 
In the March number of the “ Geological Magazine ” we 
find a review of some recent boohs on Petroleum and Oil- 
Fields. In the course of this review the writer takes occa- 
sion to remark on the absence of satisfactory information 
as to the geological history of bitumen and bituminous 
fluids. Differing in this respect from coal, which usually 
occurs in a definite manner in certain formations, petro- 
leum has been obtained from nearly all of the formations. 
So multitudinous are the modes of its occurrence, so con- 
cealed are its hidden sources, if apparently of recent ori- 
gin, or so utterly lost, if of ancient date, that it is scarcely 
a wonder that geologists have allowed it to retain a 
known but an unexplained existence ; that, at the best, but 
■hazy ideas of the truth have been thrown out amongst 
a host of unnatural theories. Two theories have met with 
more favor than others. These seem to be t( special 
mineralization ” and “ distillation.” 
The reviewer then goes on to remark that the best evi- 
dence in favor of the first-mentioned theory, that of Mr. 
G. P. Wall, appears to be defective in that it does not 
supply the necessary connection in the series of phenomena 
alleged to take place on the conversion of vegetable matter 
into asphalte. 
Having examined and explained the distillation theory 
which in his view is the mere plausible, and which ascribes 
the origin of asphaltic deposits to pre-existing bituminous 
formations (such as coal, &c.) the reviewer sums up the 
evidence in favor of each of those theories, very much in 
favor of that of distillation. 
