72 PROCEEDINGS OF THE WASHINGTON MEETING 



The following papers were then presented : 



F AGGLOMERATE, A DETRITAL ROCK AT BATTLE MOUNTAIX, yEVADA 



BY ANDREW C. I.AWSON 



{AJ)stract) 



The paper is a brief description of an ancient alluvial fan formation ob- 

 served at Battle Mountain. The alluvium has been thoroughly indurated by 

 silicification in the same way that many sandstones are converted into quart- 

 zites, so that the rock is one of the most resistant to erosion in the region. Its 

 constituent materials are angular fragments of various preexistent rocks, and 

 its analogy with the modern incoherent waste of the desert alluvial fans is 

 obvious. The rock is interesting not only as a petrographical type worthy of a 

 name, but also, from a geological point of view, as a formation revealing a 

 physiographic condition of the Great Basin province as a land surface in 

 probably Mesozoic time. 



Discussion by Hilgard, Londerback, and Eogers. 



ORTHOCLASE AS A VEIN MINERAL 



BY AUSTIN F. ROGERS 



(A1)St7'aCt) 



Orthoclase as a vein mineral is described from two localities — Rawhide, Ne- 

 vada, and Weehawkeu. New Jersey. At Rawhide there is a quartz-orthoclase 

 vein, the orthoclase having the habit of adularia, the quartz having peculiar 

 optical anomolies. At Weehawkeu narrow veins of orthoclase and calcite 

 carrying pyrite and chalcopyrite occur in diabase. The orthoclase at this 

 locality also has the habit of adularia. 



Discussion bv Lawson, Louderback, and W. S. T. Smith. 



SOME GENERAL FEATURES OF THE MIOCENE OF THE SOUTHERN COAST 

 RANGE REGION OF CALIFORNIA 



BY GEORGE D. LOUDERBACK 



(AbstrcK't) 



A general statement of the broader features aud geological relations as ob- 

 served, especially in Ventura, Santa Barbara, and San Luis Obispo counties, 

 and discussion of the grouping and nomenclature of formations involved. 



Discussion bv Lawson, Anderson, Moron, and ^lerriam. 



