44 PROCEEDINGS OF THE ACADEMY OF [Feb., 
MOLLUSCA OF THE SOUTHWESTERN STATES: IV. THE CHIRICAHUA 
MOUNTAINS, ARIZONA. 
BY H. A. PILSBRY AND J. H. FERRISS. 
CONTENTS. 
Introduction. 
_I. Conditions determining the isolation of snail colonies, p. 46. 
II. Influence of environment on the shell, p. 47. 
Ill. Factors in the formation of species and races, p. 49. 
IV. Distribution of Chiricahuan mollusks, p. 50. 
V. Systematic descriptions of species, p. 53. 
The Chiricahua Mountains stand near the southeastern angle of 
Arizona, extending for about fifty miles from northwest to southeast, 
being one of the numerous short roughly parallel ranges of that part 
of New Mexico and Arizona. The Peloncillo range, lower and very 
arid, sharply limits the horizon eastward, distant about twenty miles. 
The next range westward is the Dragoon Mountains, fully thirty 
miles away. These ranges are separated by mesa having an elevation 
of about 5,000 feet, but lower in the middle. 
The northwestern end of the range is known as the Dos Cabezas 
Mountains, being separated from the main range by a depression 
to 5,500 feet near Fort Bowie. The mountains as far south as White 
Tail Canyon are rather arid, the trees stunted oaks and pifions, with 
small beech, walnut, willow, buttonwood, etc., in the canyons. The 
Cave Creek region is much more verdant and at elevations of 8,000 
feet and over there are fine pine and spruce forests.!_ The mountains are 
rugged, almost everywhere cut into sharp ridges and peaks, the slopes 
steep and stony or rocky, often broken by cliffs. The accompanying 
map gives a general idea of the positions of the various valleys or 
canyons mentioned herein. Various maps of single canyons give the 
locations of collecting stations.’ 
1 For an account of the flora of the Chiricahuas see J. C. Blumer, The Plant 
Geography of the Chiricahua Mountains, Science, XXX, p. 720, November 19, 
1909. 
2 The general map of the range and that of Cave Creek Canyon were drawn 
from sketches made by both authors, with some few additions to the general 
map from a map of the Chiricahua Forest Reserve, published by the Forest 
Service, U. S. Department of Agriculture, 1906. This map is very inaccurate 
in many details, yet useful in the absence of anything better. The other maps 
of canyons are from the note-book of one of the authors. Elevations where 
given herein are in part from the Forest Reserve map, in part estimated; and 
all must be accepted as only approximate. 
