THE CORDILLERAN SECTION 729 



AFFINITIES AND STAGE OF EVOLUTION OF THE JOHN DAY CARNIVORA 

 BY JOHN C. MERRIAM 



TEHACHAPI VALLEY 

 BY ANDREW C. LAWSON 



[Abstract] 



Tehachapi valley lies on the summit of the southern Sierra Nevada and 

 drains to Mohave desert on the one side and to the San Joaquin valley on the 

 other, in both cases through steep rocky gorges. The valley is about 12 miles 

 long and at its widest part 5 miles or more wide. Its floor is a nearly flat sur- 

 face of alluviation and the divide for the drainage is in the middle of this flat 

 floor. The paper is a description of this valley and a discussion of its origin 

 as a geomorphic feature. Other similar features in the same region are also 

 discussed in the paper. 



The paper was illustrated by lantern slides. It was published as 

 Bulletin of the Department of Geology, University of California, volume 

 4, no. 19. 



MIDDLE KERN RIVER 

 BY ANDREW C. LAWSON 



Published as Bulletin of the Department of Geology, University of 

 California, volume 4, no. 16. 



The Section then adjourned for luncheon. 



At 2 p m the session was resumed and the following papers were read : 



IGNEOUS ROCKS OF THE NORTHWESTERN BLACK HILLS 

 BY W. S. TANGIER SMITH 



[Abstract] 



The igneous rocks of this region belong to two widely separated periods of 

 time, the first pre-Cambrian, the second probably post-Cretaceous or Eocene. 

 The Eocene (?) igneous rocks form an interesting group of closely related 

 types, all of which have probably been derived by differentiation from a com- 

 mon, somewhat soda-rich magma. They constitute the laccolithic intrusions 

 characteristic of this part of the Black hills, and appear also as associated 

 minor masses. 



Brief petrographic descriptions of the more important of these rocks, as 

 well as their general relationships, are given in the paper. 



CALCITE FROM TERLINGUA, TEXAS 

 BY A. S. EAKLE 



Published in Bulletin of the Department of Geology, University of 

 California, volume 5, no. 6. 



