68 CALIFORNIA ACADEMY OF SCIENCES. 



the lower end of the valley below El Capitan, the spot 

 being well shaded and always moist from a spring. Near 

 here, the specimen of H. inonuoumu was also found by 

 Mr. Knapp. 



No land shells were found above 4,800 feet on the west 

 slope, the soil being mostly granitic, and frosts frequent 

 even in midsummer. The eastern slope is however cov- 

 ered to some extent with metamorphic rocks in which 

 limestone is found, crossing the summit between the high 

 granitic peaks, and may have the effect of favoring the 

 higher range of species in Bloody Canon. This bed of 

 a former glacier has a little lake, formed by the moraine 

 left by the ice, acting as a dam to the water running dowm 

 toward the east. Near the head of this lake is a grove 

 of poplars, where were found the land shells near 8,000 

 feet elevation. 



There were some ponds just at the summit, 10,765 feet 

 altitude, which I examined carefully, but found nothing, 

 from which it seems probable that there are none to be 

 found above 9,700 feet in this latitude. 



The special chmatic conditions at Soda Springs are of 

 considerable interest. Situated at an altitude of 8,700 

 feet, near the lower end of Tuolumne Meadows, only 

 eleven miles from Mono Pass and the Sierra crest, with 

 snow lying perpetually near by at altitudes not much over 

 2,000 feet greater, the summer is of necessity short and 

 the nights cold, with frequent frosts even in July and 

 August. As is well known, the great Tuolumne glacier 

 once swept over these meadows, evidence abounding on 

 all sides in the form of polished and scored rock surfaces, 

 and undulating, hollowed and rounded slopes of granite. 

 In hollows thus formed, not far from Mr. Lembert's cabin 

 at Soda Springs, water collects from the melted snows, and 

 having no outlet forms shallow ponds, half filled with sed- 



