CONTEXTS 379 



Page 



Natural coke '. 465 



Potholes 465 



Quarries 465 



Eainprints 466 



Recent volcanic features 466 



Relief maps 466 



Ripple- marks, mud and water 467 



River flats and freshet deposits 467 



River meanders 467 



River terraces (old and new) 467 



Sand dunes , 468 



Schistosity, cleavage, and jointing 468 



Shore cliffs 469 



Sinkholes 470 



Spheroidal structure 470 



Springs 470 



Spring deposits 470 



Tepee buttes •. 471 



Tufaceous lake beds 471 



Unconformities 471 



Veins 471 



Waterfalls 472 



Weathering 473 



Wind erosion 474 



Introduction 



This catalog gives the titles of all the photographs which have been 

 donated to the Society up to the end of May, 1902. It is arranged 

 alphabetically by states and countries. The numbers are from 1 to 

 1418. There is also a subject index with headings of some of the prin- 

 cipal geologic phenomena under which the numbers and brief titles of 

 the photographs are given in numerical order. 



The original number of photographs was 2,037, as given in catalogs 

 of accessions published in the Proceedings from volumes 1 to 12. It was 

 known for some time that the collection had become too bulky and con- 

 tained a large amount of worthless material. On my suggestion a com- 

 mittee was appointed, consisting of G. K. Gilbert, J. S. Diller, and myself, 

 with authority to exclude the undesirable views. This was done in 1901, 

 photographs being rejected only when there was unanimous agreement. 

 By this means the collection was reduced to its present size. It was 

 rearranged by states and renumbered; photograph No. 1 representing Ala- 

 bama, and photograph No. 1359 concluding those under Wyoming ; then 

 follow Nos. 1360 to 1418, including various miscellaneous views which 

 could not be arranged geographically. Many minor changes were made 

 in the arrangement of the prints so as to materially diminish their bulk. 



