42 
Florida geological survey— 14TH annual report 
In connection with the preparation of the geologic map, the United 
States Geological Survey contributed through the Director notes on the 
geology of west Florida made by C. Wythe Cooke. A part of the field 
work incorporated in this report was done in co-operation between the 
United States Geological Survey and the Florida Geological Survey 
in 1917. 
As a convenience in reference, a number of well logs previously pub¬ 
lished have been copied into this report. These logs are from earlier re¬ 
ports of the Florida Survey and from the United States Geological Sur¬ 
vey, and are in each instance credited to the source from which taken. 
The field work for this report was done jointly by the authors chiefly 
during the latter part of 1920. However, record of wells drilled since that 
time have been included, thus bringing the report up to the date of 
publication. 
COMPOSITION AND PROPERTIES OF OIL AND GAS 
The petroleum compounds, oil and gas, are natural products found 
within the earth, composed essentially of hydrogen and carbon. In 
addition to hydrogen and carbon, there may be present in oils a small 
amount of oxygen, nitrogen, or sulphur. The petroleum, as found in 
nature, although consisting of only two essential elements, are of ex¬ 
tremely varied composition and have been shown by chemical analysis 
to form compounds which may be arranged in several series, and of 
each series there are many members. The more common petroleum 
compounds are those which are included in the paraffin, olefin and nap- 
thene series. Less common in nature are compounds of the acetylene 
and benzine, and several other series. 
The petroleum compounds of the paraffin series, also known as the 
methane series, consist of hydrogen and carbon combined according to 
the following definite ratio: In all the compounds of this series there 
are two more than twice as many hydrogen atoms as there are carbon 
atoms. Members of this series, accordingly, include compounds ex¬ 
pressed by the general formula: CnH(2n-)-2), in which “n” is the 
number of carbon atoms. In the case of a compound having six carbon 
atoms, the formula thus would be CeH (2X6+2) or CeHi4. 
Marsh gas, or methane, is a gas of the paraffin series of compounds, 
for which the formula is CH4. Another gas of this series, ethane, has 
the formula C2HG. 
