112 C. E. VAN ORSTRAND 
lin Furnace, New Jersey, and the upper peninsula, Michigan (Table 
I), tend to support this conclusion. Core-drill holes in areas of un- 
disturbed igneous rocks would give us valuable information on this 
important question. 
RECAPITULATION 
In order to give a general idea of the areal distribution of gradients, 
the maximum and minimum reciprocal] gradients have been tabulated 
in those areas in which there are a considerable number of observa- 
tions. We have for the first 1,000 feet: 
Feet per °F. Meters per °C. 
Appalachian Mountains 68-131 37-72 
Wyoming 19-74 10-41 
Southern California 40-83 22-46 
Louisiana S-7/ 18-31 
Kansas 46-82 25-45 
Oklahoma 37-162 20-89 
Texas 22-156 12-86 
New Mexico 130-228 71-125 
The well at Albany, Alabama, is not included in the preceding 
summary. The lowest temperatures are found in the Permian basin 
(12)—that is, southeastern New Mexico, western Kansas, western 
Oklahoma, and western Texas. The highest oil-field temperatures occur 
on the salt domes of the Gulf Coast, including northern Louisiana, 
and on structures of large closure in Wyoming. 
The computed averages are as follows. 
Feet per °F. Meters per °C. 
Crests of 57 structures 49.8+ 1.2 27-3+0.7 
Flanks of 57 structures GtiSE Ta) 3451-1O 
138 locations, including flanks of oil structures 65e2-en 0 35-8+0.9 
9 locations, excluding flanks of oil structures 108.0+ 10.6 59-3+5.8 
4 locations in oil fields, Tuxpam, Mexico GHoHaE tse) 19.9+1.0 
2 locations in oil fields, Alberta, Canada 52.5 28.8 
9 mines, northern Ontario, Canada 156.0+ 7.3 85.6+4.0 
The preceding results, with the exception of the oil fields at Tux- 
pam and the mines in northern Ontario, are the averages for the first 
1,000 feet. 
From Table IV and the preceding tabulations, we have the follow- 
ing averages for the indicated successive ranges of depths. 
100 to 100 to 100 to roo to 
I,000 2,000 3,000 4,000 
Feet Feet Feet Feet 
Crests of 57 structures 49.8 50.6 50.0 47-4 
Flanks 62.1 e7a 56.0 Brigg! 
138 locations, including flanks of oil struc- 
tures 65.2 62.6 59-6 54-6 
9 locations, excluding flanks of oil struc- 
tures 108.0 IOI.o 95-7 — 
772 
