270 The American Geologist. October, 1902. 
CORRESPONDENCE. 
A Carboniferous Coal in Arizona. The fact of the existence 
of a small deposit of anthracite coal in the Chiracahua mountains, 
Cochise county, Arizona, has been known for some years, but it is 
so disturbed by faulting and by the intrusion of eruptive materials that 
no practical use has ever been made of it. 
Having occasion to visit this range of mountains in July I made it 
convenient to go by the old prospect holes. Upon examination I was 
surprised to find that it did not belong to the Triassic as I had always 
supposed, but it was overlain by beds of limestone of the Upper Car- 
boniferous. 
In a record of a former trip to these mountains* I noted the oc- 
currence of the Upper Carboniferous thus : 
"In the Chirachua mountains, on Cave creek, above Mr. Reed's 
house, we found exposures of platy limestones closely resembling 
those at the base of these beds. 
"North of this, between Cave creek and Turkey creek, the expo- 
sures of Carboniferous limestones are very satisfactory. They dip SW 
from 30° to 45° ; and the section is repeated by the occurrence of faults. 
"The upper limestone appears to have a thickness of 1200 feet, 
and is underlain by 300 feet of limy clays with interbedded limestones. 
Fossils are abundant; but, as is the case throughout this area, they are 
all siliceous pseudomorphs, and are not well preserved. Dr. Schu- 
chert determined the following species : Syringapora multattcnuata, 
Campophyllum torquium (f) ; Lophophyllum prolifcrum; Rcticeolaria 
pcrplcxa; Diclasma bovidcns; Sciiiiiiiila argcntca; Euomphaliis sub- 
quadratus; Mcckdla striatacostata; and fragments of Productw;, Spir- 
ifcr, and Dcrbya ; so that the horizon is established as Upper Carbon- 
iferous. There appears to be a slight unconformity near the middle 
of the beds, but it may be due to faulting or slipping." 
Although there is considerable faulting I found a clean section 
showing that the coal occurs in clays and slates which I did not find 
exposed on my first trip and which underlie the beds above described. 
I also found the Triassic beds in their proper position far above 
this horizon, so there can be no question as to the Carboniferous age 
of this particular coal deposit. 
While it may be that this deposit has no connnercial value, its 
occurrence is of scientific interest as showing that conditions suitable 
for the formation of coal existed during the period of the Upper 
Carboniferous at a great distance to the west of any previously re- 
corded locality. E. T. Dumble. 
Houston, Texas, Aug. 12, 1902. 
•"Notes on the Geology of Sowtheastern Arizona," Traps. Arn. Jpst. Mia, 
Bng. Vol. xxxi. 
