BULL. GEOL. SOC. AM. 



VOL. 22, 1910, PL. 10 



FiGruK 1. — Ir.LrsritA'j'iox of CoxtuoFv i-.v a FuvcruRio Svstk.m at hi(;ii Ai/ititdios withix a 



DivSKKT Region 



A spaced joint systom is betrayed in the rock wnll ol' tlie middle distance, while a regular 

 sagging of the horiz(jn line above visible fracture phmes is to be made out. The altitude is 

 12.000 feet upon the Tian Shan plateau. ( I'hotograi)h l)>- i:iis\v()rrh Huntington. ) 



Figure 2. — View lookix(; ixnvs rin: Sakaxac Kivkr ix the Vicixitv of Cauvvilee 



The perfect joint structure within the I'otsdam sandstone has brought about rectangular turn- 

 ings in the river. (After a photograpli by W .T Mc(jee, through courtesy of C E. Peet.) 



RELIEF FORMS CONTROLLED BY THE FRACTURE SYSTEM 



