1915.] NATURAL SCIENCES OF PHILADELPHIA. 399 



Alt. 12, diam. 19.6 mm.; umbilicus 2.8 mm.; 4f whorls. 



Santa Rita Mountains at Station 17 (Camperel Caiwon), on the 

 northeastern flank of Old Baldy. Type No. 112J65, A. N. S. P. 



We regret that the jar containing the soft parts of this species 

 proved leaky, and its contents were lost. It seems to be related to 

 S. granulatissima, as the sculpture is very similar. 



V. Small Ranges and Hills of the Santa Cruz River Valley. 



Between Tucson and Nogales and the Santa Rita and Baboquivari 

 Mountains there are many buttes and ranges of hills or small moun- 

 tains, a few of which we visited, finding in each a special species of 

 Sonorella and sometimes a few small shells. 



Among the more important ranges which should be investigated 

 we may mention the Tumacacori (or Atascoso) range, an extensive 

 mass of arid looking mountains, extending south to the Mexican 

 line, and probably supporting little but Sonorella. They are easily 

 accessible from the Sonora R. R., being about 6 miles from ''Siding 

 No. 4." These mountains on the south pass into the Sierra de los 

 Pajaritos, which lie west of Nogales — "a confused mass of rocky 

 crags, peaks, flat-topped mountains with vertical sides, enormous 

 trachyte dykes, steep narrow ridges and deep canyons." They are 

 covered with "a fine growth of oak, juniper and manzanita, while 

 magnificent walnut, sycamore and ash trees line the canyons." 

 Water supply precarious except in the wet seasons. These fine 

 mountains are unknown to the conchologist. 



Various species reported from Tucson were certainly brought 

 there from more or less distant localities. Sonorella granulatissima, 

 reported by Bartsch, Smiths. Misc. Coll., Vol. 47, p. 193, and Ash- 

 munella varicifera Ancey are Huachucan species. The following 

 species were taken in the drift debris of the Santa Cruz River, near 

 Tucson, chiefly above the bridge. The fresh-water shells are mainly 

 fossils, washed out of, or exposed upon the low dirt banks, where 

 the stream has cut down through a former 'Cie7ieg a. Part of the land 

 shells probably washed in from the Tumamoc and other eastern 

 foothills of the Tucson Range. We found Bifidaria tuba and Thysan- 

 ophora hornii on the Tumamoc Hills, and with other minutiae, in 

 debris washed down from the hills at the hill terminus of Congress St. 



Thysanophora hornii (Gabb.). 



HoLosPiRA FERRissi SANCT^CRUCis P. and F. (see p. 388). 



Zonitoides singleyana (Pils.). 



SUCCINEA AVARA Sav. 



