238 Native Bitumens and the Pitch Lake of Trididad. [ April, 
springs, it is likely, in a manner similar to that just described, to 
lose its more volatile ingredients and become semi-solid like min- 
eral tar, or solid like asphalt. And so it happens that many of 
the smaller deposits of asphaltum in this and other countries are 
simply dried up petroleum, and are of animal origin. The great 
deposits of the globe, however, those which constitute the prin- 
cipal source of the asphaltum employed in the arts, do not appear 
to have been formed in this way; but have, in most cases at least, 
been derived directly, after the manner of coal, as already 
explained, from decaying vegetation. 
Extensive deposits of asphaltum, such as that for which the 
island of Trinidad is celebrated, are commonly regarded as some- 
thing exceptional, something out of the natural order, a freak of 
nature. This notion is without foundation in facts, for asphaltic 
substances are not only widely disseminated, as already stated, 
but in not a few localitics, which form a zone girdling the earth, 
they are accumulated in such vast abundance as to ensure an 
unfailing supply for man’s purposes for all time to come. 
A list of the localities where asphaltum is especially abundant 
may further enforce this view, these are: Cuba, several of the 
Windward islands, especially Trinidad and Barbadoes, the Carib- 
bean shore of South America, particularly the province of Mara- 
caybo, Caxitambo and Berengela in Peru, where are lakes of 
asphalt similar to that on Trinidad ; Mexico, Texas and California 
in North America, Persia and Arabia, Palestine on the shores of 
the Dead sea and on Mount Lebanon, Ionian islands, France, 
Switzerland and Portugal, It is a curious fact that the asphalts 
are confined almost wholly to tropical and sub-tropical regions. 
There appears to be in low latitudes some general climatic or 
other condition which has in many cases determined the conver- 
sion of vegetable matter into bitumen instead of coal. 
The largest deposit in Europe is probably that in the Val-de- 
Travers, Neufchatel, Switzerland, which has been worked for 
more than one hundred and fifty years. This occurs in rocks of 
Cretaceous age; but as a rule the great masses of asphalt are 
found in connection with Tertiary strata. This is the geological 
position in Trinidad, Barbadoes, Peru and other points in South 
America and in California. Trinidad is composed chiefly of Ter- 
tiary and Secondary beds, the former predominating ; but toward 
the north the island otherwise quite low, is bordered by a bold 
