6 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



RESEARCHES AND EXPLORATIONS 



An important part of the Institution's work in increasing scientific 

 knowledge is the exploration of regions imperfectly known to science. 

 Although the limited funds of the Institution sharply restrict the 

 number of expeditions which it is able to put in the field, neverthe- 

 less it is often found mutually advantageous to cooperate with other 

 agencies in field work, and the Institution thus has an interest in a 

 considerable number of expeditions each j^ear. Many of them are 

 conducted under the direct supervision of the heads of several of 

 the bureaus under the Institution, and accounts of these will be 

 found in the reports appended hereto on the National Museum, the 

 Bureau of American Ethnology, and the Astrophysical Observatory. 

 A few of the expeditions will here be described briefly, in order to 

 give an indication of the nature of the work undertaken, 



GEOLOGICAL EXPLORATIONS IN THE CANADIAN ROCKIES 



During tlie field season of 1924, your secretary carried on his usual 

 geological woik in the Canadian Rocky Mountains, with the inten- 

 tion of completing the reconnaissance begun some years ago of the 

 pre-Devonian formations north of the Bow Valley. The weathei* 

 was unusually unfavorable, and on 42 days out of the season it 

 was very difficult and sometimes impossible to carry on the field 

 work. The chief problem attacked was the determination of the 

 proper classification of the great Lyell limestones. In order to 

 .solve this it was necessary to find fossils in them, and during the 

 past six seasons all such attempts were unsuccessful. 



A section was measured from Fossil Mountain, situated northeast 

 of Lake Louise station on the Canadian Pacific Railway, eastward 

 into Oyster Mountain, the main north and south ridge of which was 

 found to be formed of the Lyell limestones. Two glacial cirques, 

 named Cotton Grass and Tilted Mountain, cut deeply into this ridge, 

 and in these the base of the Lyell formation was uncovered, as well 

 as the shales and oolitic limestones of the underlying Bosworth 

 formation. The brook running out of the glacial lake in the bottom 

 of the southern cirque was followed over the ledges of Lyell lime- 

 stone westward to Tilted Mountain Falls, where it drops into the 

 canyon valley of upper Baker Creek. Everj'^where the hard, un- 

 fossiliferous, light gray limestone was encountered, except near the 

 edge of the cliffs above and east of the falls, where long narrow 

 strips covered with grass and trees occur between the north and 

 south ledges. An approach was made from the southern bank of 

 the brook, and on a rounded, glaciated ridge of the gray magnesian 

 Lyell liuiestonc there was found, interbedded in the Lyell, an out- 

 crop of thin layers of a bluish-gray limestone which contained frag- 



