REPORT OF THE SECRETARY 29 



on fresh-water fishes. Botanists of the staff gathered material for 

 a proposed new Flora of the District of Columbia, the object sought 

 being a thorough knowledge of the Washington-Baltimore region. 



Geology. — Under a cooperative arrangement with the United 

 States Geological Survey, Dr. W. F. Foshag, curator of mineralogy 

 and petrology, accompanied by Carl Fries, of the Geological Survey 

 staff, made a 3-month survey of the tin resources of Mexico. All 

 the important mining districts of Mexico included within the states 

 of Michoacan, Hidalgo, San Luis Potosi, Queretaro, Aguascalientes, 

 Jalisco, Zacatecas, and Durango were visited and the deposits studied 

 as to their geology, mineralogy, and commercial potentialities. The 

 largest potential deposits are the placer sands derived from granite 

 intrusions in San Luis Potosi. The deposits in the rhyolitic rocks 

 are, in most cases, small and of little importance. 



Dr. C. E. Resser, curator of stratigraphic paleontology, spent 3 

 months in field work, chiefly in the Rocky Mountains, assisted by 

 Charles H. Frey, 3d, of Lancaster, Pa. Dr. Resser left Washing- 

 ton on June 25, making first a brief stop in southwestern Virginia. 

 His next objective was the Cambrian section in the Ozark Mountains, 

 where several days' work enabled him to familiarize himself with 

 these strata. Only indifferent fossils were found, as most of the 

 Cambrian rock does not carry fossils. He continued then to examine 

 Cambrian deposits in Colorado in the Front, Mosquito, and Sawatch 

 Ranges and the Glenwood Springs Canyon. Ten days in the State 

 permitted examination of several sections. Dr. T. S. Lovering, of 

 Ohio State University, who was mapping the region about Oilman, 

 assisted materially in showing the sections there. At the Grand 

 Canyon National Park in Arizona Dr. Resser examined new localities 

 under the guidance of Park Naturalist Edwin McKee during a 3- 

 day trip to Peach Springs and Meriwitica Canyons, 150 miles west 

 of Grand Canyon Village. Some fossils were found and physical 

 measurements made. In the Wasatch Mountains the party checked 

 on the position of certain faunas and on the stratigraphy, which had 

 been questioned. Fine collections were made at critical points. At 

 the Green River Lakes, one of the most beautiful spots in America, 

 Dr. Resser's party found a section 850 to 1,000 feet thick, representing 

 both Middle and Upper Cambrian, carrying a few fossils. Several 

 sections were studied in Montana, notably on Squaw Creek in the 

 Gallatin Range, Newland Creek, Little Birch Creek, and Deep Creek 

 in the Belt Mountains, and several localities near Three Forks, Mont. 

 Particularly fine material was secured at several of these localities. 

 Advantage was taken of the new road constituting the northeastern 

 entrance to the Yellowstone to study the excellent section at Bear- 

 tooth Butte. Here some good collections were made. On the return 



