Studies in the Sierra 



71 



most entirely to the number, magnitude, declivity and mode of 

 combination of the glacial system of each. The similarity of their 

 ground-plans is obvious from a single glance at the figures ; their 

 cross-sections are no less similar. One of the most characteristic 

 from each of the valleys under consideration is shown in Figs. 

 4, 5 and 6, drawn on the same scale. 



Fig. 4. — Section across the Hetch 

 Hetchy Valley, or 

 lower Tuolumne Yosemite 



Fig. 5. — Section across the Kings River 

 Yosemite 



Fig. 6.— Section across Merced Yosemite 



Fig. 7 



The perpendicularity of Yosemite walls is apt to be greatly 

 over-estimated. If the slopes of the Merced Yosemite walls were 

 to be carefully measured with a clinometer at intervals of say 

 100 yards, it would be found that the average angle they make 

 with the horizon is less than 50°, as shown in Fig. 7. It is not 

 possible that the bottom could drop out of a valley thus shaped, 

 no matter how great the upheaval or down-heaval, or side- 

 heaval. 



Having shown that Yosemite, so-called, is not unique in its 

 ground-plan or cross-sections, we will now consider some of the 

 most remarkable of its rock forms. The beautiful San Joaquin 

 Dome in the canon of the San Joaquin, near the confluence of 

 the south fork, looking south (Fig. 9), shows remarkable re- 

 semblance to the Yosemite Half Dome, as seen from Tenaya 

 Canon (Fig. 8). They are similarly situated with reference to 

 the glaciers that denuded them, Half Dome having been assailed 



