90 PROCEEDINGS OF THE ACADEMY OF [Feb., 
a few feet above the bed of the canyon, at and below the mouth of 
Indian Creek, the shells are equally small, 12 to 13 mm. in diameter. 
The station is deficient in herbage, more barren than higher up the 
slopes. 
In the Box Canyon of White Tail we found a colony which differed 
from all other lots of the White Tail region in sculpture, the striation 
being distinct and rather sharp on the base, as in typical chiricahuana, 
and with very weak traces of fine spiral lines. The peripheral keel 
projects more, approaching the shape of the race from Big Emigrant 
Canyon; otherwise the shape, size and number of whorls is as in 
O. c. obsoleta. The conditions at this station were unfortunately not 
noted particularly. 
No specimens of this shell were taken by Ferriss and Daniels in 1907, 
as they did not explore the limestone ridges. In 1908 Ferriss and 
Pomeroy found it again in Hand’s Pass, over the range from White 
Tail, in the head of Pinery Canyon. 
The embryonic shell is strongly, regularly ribbed. The shell has 
5+ whorls, rounded, arcuate, keel nearly obsolete near the aperture 
in mature shells; aperture nearly round, the angle formed by the 
peripheral keel hardly perceptible. 
Ni). ee ee ent FOE: <1 reno 83 
TDI «ass eee kee 16 144 144 154 14 
They were found for several miles upon both sides of the trail in 
the scattered stone upon the hillsides and around the cliffs. 
In the head of Mackey’s Wash, sloping to the north, a few were 
found, but no aged shells. The major spirals upon the under surface 
are represented by very low, obtuse ridges. The keel becomes very 
obtuse on the last whorl near the aperture. O.c. obsoleta was also found 
in the head of Onion Creek (between Paradise and Jhu Canyons). 
In 1907 Mr. Ferriss passed over the wide part of the range from 
Paradise to the mouth of Rucker Canyon and Shake Gulch, some 
25 miles from the Cave Creek Station, and here again O. c. obsoleta 
(fig. 13 6, c) was found in a foothill known as Limestone Mountain, 
about ten miles in length and some 7,000 or 7,500 feet above the sea. 
These are the largest specimens so far found, thick and rounded, 
opaque white or pink-white and very little clouded. The wrinkles 
were coarse but obtuse upon the upper surface, the base smooth, 
without a trace of spiral lines. 
)- AeReta PO eae mere LS 11 104 1 12 9 
Dear ey ee ee 164 16 154 154 15 
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