PROCEEDINGS OF THE ACADEMY AND AFFILIATED 



SOCIETIES 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



The 265th meeting was held in the lecture room of the Cosmos Club, 

 February 12, 1913. 



An informal communication was presented: 



Cone in cone structure in coal from St. Anthony, Idaho: E. G. Wood- 

 ruff. Cone in cone structure is not uncommon in clay and shale, but 

 unusual in coal. The specimens exhibited from the St. Anthony coal- 

 field, Idaho, show this structure well developed on the surface but not 

 developed within the specimens, tho shearing is shown. Bed from 

 which the sample is taken is crushed and faulted. Slickensiding is 

 common. The cone in cone genetically in this case seems to be closely 

 related to slickensiding. The complete explanation is not offered. 



The formal communications were: 



Certain metallic minerals as precipitants of silver and gold. Chase 

 Palmer and Edson S. Bastin. The paper will be pubUshed in no. 2, 

 vol. 8, of Economic Geology, and in shorter form in the Transactions 

 (New York meeting) of the American Institute of Mining Engineers. 



Time relations of glacial lakes in the Great Lakes region: Frank Lev- 

 ERETT. The following tabulated statement of the order of development 

 of lakes in the several basins sets forth the tentative correlation based 

 upon a study of the moraines, lake outlets, and other features which bear 

 upon correlations. The writer is responsible for the present tabulation 

 but is indebted to various other geologists for data bearing upon the 

 direction of outlet of the several lakes at different lake stages. 



Order of development of glacial lakes 



1. General recession of ice border but with some oscillation. 



Lake Maumee, discharge (a) By Fort Wayne to Wabash River. 



(b) By Imlay outlet to Lake Chicago. 

 Lake Saginaw, discharge in later stage by Grand River outlet to 



Lake Chicago. 



Lake Chicago, discharge by Chicago outlet to Illinois River. 



2. General recession of ice border. 



Lake Arkona, discharge by Grand River outlet to Lake Chicago. 

 Lake Chicago, discharge by Chicago outlet to Illinois River, 



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