proceedings: biological society 311 



and east sides of the basin is believed to correspond to the Gebo on 

 the west side, Bearpaw (?) to part or all of the Meeteetse, and the 

 Lance (?) to the Ilo. No evidence has been obtained in Bighorn 

 Basin to prove that the beds designated Bearpaw (?) or Meeteetse 

 are marine. 



Two unconformities are recognized in Bighorn Basin — one at the 

 base of the Fort Union and the other at its top. Discordance in dip 

 and lenses of conglomerate mark the unconformities. 



Structurally Bighorn Basin is a vast geosyncline with minor folds 

 developed on its flanks. Its axis trends northwest-southeast. The 

 axes of the minor folds trend in the same general direction but more 

 nearly parallel to the adjacent mountains. The upfolds are character- 

 ized by narrow flanks and steep dips on the mountainward sides and 

 broad flanks and gentle clips on the basinward sides. 



The anticlines and domes that produce most of the Oil and gas are 

 nearest the major axis of the basin. Many of the anticlines plunge 

 into the basin and are of little value as oil and gas reservoirs. 



Most of the anticlines are developed in rocks older than Wasatch, 

 but in a few places that formation is deformed. Such a condition 

 suggests a greater deformation of the beds on which the Wasatch rests. 



Only a few faults are present. The greater number of them extend 

 parallel to the strike of the beds. An unusual condition obtains at 

 Greybull, where dip faults throw out the middle of the oil and gas field. 



Carroll H. Wegemann, Secretary. 



THE BIOLOGICAL SOCIETY OF WASHINGTON 



The 554th regular meeting of the Biological Society of Washington 

 was held at the Cosmos Club, Saturday, April 8, 1916, at 8 p.m.; called 

 to order by President Hay, with 65 persons present. 



The President called attention to the recent death of Wells W. 

 Cooke, Treasurer of the Society, and announced the appointment of 

 Messrs. Hollister, Gidley, and Wetmore to draw up appropriate 

 resolutions. The President also announced the election of Dr. Ned 

 Dearborn to the office of Treasurer, made vacant by Mr. Cooke's 

 death, also the appointment of Dr. Dearborn to the committee on 

 publications. 



On recommendation of the Council the following persons were 

 elected to active membership: Robert M. Libbey, Washington, D.C.; 

 G. K. Noble, Museum of Comparative Zoology, Cambridge, Massa- 

 chusetts; and Dr. Howard B. Ames, U. S. Navy (Retired). 



The following informal communications were made : 



Dr. R. W. Shufeldt commented upon and exhibited specimens of a 

 Japanese salamander, Diemictylus pyrrhogaster, obtained from a local 

 dealer in live animals. 



Dr. Paul Bartsch called attention to the introduction of the Euro- 

 pean agate snail, Rumina decollata, in certain parts of the southern 

 states and to the recent publication by J. B. Henderson of a book 



