

1910.] NATURAL SCIENCES OF PHILADELPHIA. 63 



about 4+ whorls, the last with some spiral lines on the upper surface, 

 sometimes very faint. 



From the west side of Big Emigrant Mountain (pi. I, figs. 11, 12, 

 18, 19) a lot of 32 living adults was taken, of almost equally small 

 size (No. 94,320). 



Diam.inmm 21.4 20.5 20 19.75 19.5 19 18.7 18.3 



No. of shells 2 2 4 6 7 9 11 



The degree of elevation is somewhat variable. In one specimen 

 (pi. I, fig. 19) the dark band is wanting. This is the only case of 

 the kind among our Chiricahua Sonorellas. 



Another lot of 35 living adult shells from another place on Big 

 Emigrant Mountain average larger. 



Diam.inmm 23 22.5 22 21.5 21 20.5 20 19.8 19 



No. of shells 1 1 17 8 7 8 1 1 



Station 6, high in the valley north of Cross J Mountain, 42 adult 

 shells, most of them "dead," measure: 



Diam.inmm 22.8 22.5 22.3 22 21.8 21.5 21.3 21 20.5 20 



No. of shells 2 3 2 6 3 4 3 10 4 5 



Most shells show spiral lines, as in those from Big Emigrant Moun- 

 tain. The specimens were taken in the area indicated in the sketch 

 on p. 87, but similar dead shells were seen throughout the valley, on 

 both sides of the ravine. The rock of tliis valley is limestone. 



Eastward from this valley (.Station 6) a rugged ridge of coarse 

 crumbling granitic rock runs towards the mouth of the canyon (see 

 map). Five dead shells found on the outer side of the crest of this 

 ridge are like those from the valley, but smaller, diam. 18.5 to 20.5 

 mm. 



Station 5. Among rocks at and near the north side of the summit 

 of Cross J Mountain. The rock here is angular, friable and cherty. 

 The shells, 29 adults, mostly "dead," resemble the larger colony from 

 Big Emigrant Mountain, most of them showing fine spiral lines. The 

 elevation is estimated at 8,000 feet. See sketch on p. 87. 



Diam.inmm 23 22.8 22.2 22 21.8 21.5 



No. of shells 2 1 1 5 4 1 



Diam.inmm 21.2 20.8 20.5 20.2 20 19.8 



No. of shells 5 1 4 11 3 



Small form of S. optata (pi. I, fig. 17). Some very small specimens 

 were taken near the head of Big Emigrant Canyon south of Station 1 , 



