282 



PROCEEDINGS OF THE ACADEMY OF [NoV.-DeC, 



MOLLUSCA OF THE SOUTHWESTERN STATES— IX, THE SANTA CATALINA, RIN- 

 CON, TORTILLITA AND GALIURO MOUNTAINS. X, THE MOUNTAINS OF 

 THE GILA HEADWATERS. 



BY HENRY A. PILSBRY AND JAS. H. FERRISS.^ 



The Santa Catalina, in Pima County, north of Tucson, is one of 

 the large ranges of Southern Arizona, about forty-five miles in length, 

 including its Tanque Vercle and Rincon outliers, with an extreme 

 width of twenty-five miles. Mount Lemon with an elevation of 

 9,150 feet is heavily forested with yellow pine, quaking asp, cork 

 bark fir (Abies arizonica), Douglas spruce (Pseudotsuga mucronata), 

 cypress (Cupressus arizonica), other coniferous trees, large oaks 

 and an alder as tall as a pine. The male fern and the brake stand 

 here four feet in height. The Douglas spruce are eight feet in diam- 

 eter. There is a forest gloom at mid-day, and a ground covering 

 indicating a timber growth of many years without interruption by 

 fires or lumbering. Winter often brings ten feet of snow. With 

 numerous trout streams, it has the attractions, summer and winter, 

 of the deep forests along the Canadian border without their annoying 

 insects. 



In quantity and number of species of the smaller snails the north 

 slope of Mount Lemon has the best record so far. The odor- 

 shooting, rough-coated Sonorella also is here in large numbers under 

 the fallen bark of the Douglas spruce and the dead poles of the quak- 

 ing asp and cork bark fir. Unlike his brethren with a polished coat, 

 this snail seeks food and cover similar to those used by the Polygyras 

 of timbered areas in the Mississippi valley and eastward. 



The humid forest conditions of the region around Lemon Mountain 

 prevail at Soldier Camp, Kellogg's Peak, Alder Canyon, Alder 

 Springs. The Spud Rock Ranger Station and other high peaks of the 

 Rincon section, except in lacking cork bark fir, also follow Mount 

 Lemon closely in forest conditions. They have the large oaks and 

 conifers, the quaking asp, and the heavy floor of humus underfoot, 

 but not quite as many snails. 



In the valleys of Bear Wallow and Sabino creeks, at the heart of 

 the Santa Catalinas, the Arizonians of lower and hotter levels have 



1 The field work covered by this report was by Ferriss, assisted in the Blue 

 River region and the MogoUon Mountains by the late L. E. Daniels. 



