500 PROCEEDINGS OF PHILADELPHIA MEETING. 



1205. Vertical fissures in granite, north of Charity vallej'', Alpine county, CaHfornia. 



Markleevihe atlas sheet. 



1206. Moraines north of Pleasant valley, Alpine county, California. The valley 



lies immediately south 600 feet lower than the morames seen in the middle 

 of the picture. Markleeville atlas sheet. 



1207. Serrated ridges of andesite breccia. Mount Raymond, Alpine county, Cali- 



fornia. Markleeville atlas sheet. 



1208. West peak of Mount Raymond, Alpine county, Cahfornia, from Indian 



valley. The peak is composed of hornblende pyroxene andesite breccia. 

 Markleeville atlas sheet. 



1209. The summit of the Sierra Nevada, near Tower peak, Tuolumne county, Cali- 



fornia. 



1210. The crest of the Sierra Nevada, Tower peak. 



1211. Summit of the Sierra Nevada, near Tower peak, Tuolumne county, California. 



View taken in July. 



1212. From Charity valley, Alpine county, California; showing the fissures and 



glaciated granite, with lavas on the ridge tops ; Hawkins peak (hornl)lende- 

 andesitej in the distance. Markleeville atlas sheet. 



Fifty-one views presented hij Robert T. IJUl. 



Figures in parentheses are original numbers. 



12i;> (35). Costa Rica. Ira Zu volcano ; the ascent; altitude, 9,000 feet. Oak scrub 

 above limit of troj)ical forest. 



1214 (36). Costa Rica. Ira Zu volcano; the ascent above timber line; altitude, 



10,500 feet; vegetation, heath scrulj. 



1215 (37). Costa Rica. Ira Zu volcano ; ascent; outer view of crater. 



1216 (38). Costa Rica. Ira Zu volcano; outer view of crater, composed of rolling 



cinder. 



1217 (39). Inward view of north end of crater, showing craterlets and rolling 



boulder material. 



1218 (40). Costa Rica. Ira Zu volcano; inward view of outer crater, showing roll- 



ing boulders down cinder slope. 



1219 (41). Costa Rica. Ira Zu volcano; ancient floor of large crater within crater, 



showing one stratum of black lava in great mass of cinder accunm- 

 lation. 



1220 (42). Costa Rica. Ira Zu volcano ; old cliff of lava on south side ; remnant 



of ancient eruptions ; modern eruptions are principally cinder and 

 water. 



1221 (43j. Costa Rica. Ira Zu volcano; craterlets within crater, below floor of old 



crater shown in number 41. Nineteen of these were counted by Mr 

 Hill. 



1222 (44). Costa Rica. Ira Zu volcano; craterlets within crater, below floor of old 



crater shown in mnnber 41. Nineteen of these were counted by Mr 

 Hill. 



1223 (45). Costa Rica. Ira Zu volcano; craterlets witiiin crater, below floor of old 



crater shown in numbcM- 41. Nineteen of these were counted by Mr 

 Hill. 



1224 (46). Detail of slope of old crater floor shown in number 41. 



