1890.] Geology and Paleontology. 663 
marked degree. They are dark in color; they are heavy oils, their 
gravity generally ranging from 34° to 36° Beaumé, though sometimes 
falling to 40° or even 42°; they have a rank odor, arising from the 
sulphurous compounds which they contain. The oils of Canada, Ken- 
tucky, Tennessee, and of the fields in northwestern Ohio all agree in 
these respects, and the oil and gas of the Utica shale and Hudson 
River group of the state fall into the same category. 
In the preceding statements the organic matter of the bituminous 
shales has not been positively referred to a vegetable source. Such a 
source is highly probable, but it cannot be said to be fully demonstrated 
until the origin of the so-called Sporangites of the shales is finally de- 
termined. There are a few geologists who are inclined to refer these 
forms to hydroid zoophytes (animal) rather than, with Dawson, to 
marine rhizocarps (vegetable). Whatever their origin, they give rise to 
petroleum and oil of a definite character, which is in marked contrast 
to that of the limestone oils. 
Which of these theories as to the mode and time of origin of petro- 
leum has the most to commend it? š 
In conclusion, a few of the previously stated propositions in regard 
to the origin of petroleum that seem best supported will be concisely 
summarized: ` 
1. Petroleum is derived from organic matter. 
2. It is much more largely derived from vegetable than from animal 
substances. 
3. Petroleum of the Pennsylvania type is derived from the organic 
matter of bituminous shales, and is of vegetable origin. 
4. Petroleum of the Canada and Lima type is derived from lime- 
stones, and is of animal origin. 
5. Petroleum has been produced at normal rock temperatures (in 
Ohio fields), and is not a product of destructive distillation of bitum- 
inous shales, - 
6. The stock of petroleum in the rocks is already practically com- 
plete.—Zdward Orton in Ann. Report U. S. Geol. Survey, 1886-87. 
(Published 1890). 
_ Production of Salt in the United States.—In 1887 the pro. 
duction of salt in the United States was 7,831,962 barrels of 280 
pounds each. Of this, the value was estimated at $4,093,846. Mich- 
igan produced 3,944,309 barrels; New York, 2, 353,560 barrels ; Ohio 
and West Virginia, about 600,000 ; Kentucky, Tennessee, and Virginia, 
about 200,000 ; or about 7,000,000 barrels in all produced from the 
evaporation of brines. In addition, Louisiana produced 225,000 bar- 
Am. Nat.—July.—5. 
