64 ANNUAL REPORT 
Barren Tracts Enclosed by Producing Territory.—This is one of 
the characteristics of the county. As may be seen from the map these 
vary in size, position, and direction of extent. Wells drilled in them fre- 
quently yield some oil, but rarely in paying quantities. The cause for their 
existence is not understood. The rock lies at about the same elevation 
as that of the surrounding producing territory, thus apparently precluding 
the idea that the barrenness results from the position of the rock. How- 
ever in some cases the rock lies a little lower, so that it is possible that 
position may be in part at least the cause of the absence of oil. The fact 
that such tracts sometimes contain large quantities of salt-water lends 
weight to this idea. To the writer it seems more probable that the ab- 
sence of oil results from changes in the texture of the rock, by which it 
becomes too compact to serve as a reservoir. Possibly this may follow 
from a change in the rock’s composition, the carbonate of magnesia 
having decreased and that of calcium correspondingly increased. How- 
ever tests have not been made to prove or disprove this suggestion. 
It is not an easy matter at this late day to procure samples of Trenton 
from this territory. 
Size and Dufation of Wells.—This county may be considered the 
richest part of the Trenton limestone field. In making this statement, 
extent of territory, size of wells, and period of production is considered. 
Probably the largest well in the county was the Ducat, whose history has 
already been given. There were several wells having an initial produc- 
tion of 5,000 or more barrels of oil during the first 24 hours. One located 
a mile north of Hammonsburg in Henry township, is reported to have 
produced 15,000 barrels of oil per month during a year. One of the most 
recent of the large wells was drilled in 1893, and was located on the 
P. J. Brown farm, section 22, Plain township. After having flowed 
openly during 15 hours, the well was gotten under control, and then filled 
a 250 barrel tank in 52 minutes—a rate exceeding 6,000 barrels per day. 
The production of the county, however, was not derived from these 
large wells, but from those having an initial production ranging from 
perhaps 25 to 500 barrels. Wells drilled in recent years have been rela- 
tively small; those completed in 1901 rarely exceeded 40 barrels, while 
those drilled later were still smaller. In the summer of 1902 the wells 
in the western half of the county averaged about 3 barrels each per day, 
but those on the eastern half were smaller, averaging less than two barrels 
each. 3 
The average life of wells—a question frequently asked—is difficult 
to state. The territory, however, is long lived, as much so as any in north- 
western Ohio; and wells having had a heavy initial production (say 500 
barrels per day) are said to produce on the average from ten to twelve 
years. Gaugers report the average decrease in the production of a well 
to be about 12% per cent. each year. The number of new wells being 
