6 GEOLOGICAL SURVEY OF THE TEEEITOEIES. 



to advance the objects of the survey, yet the burden of executive duty 

 was so great in managing the affairs of so large an organization that a 

 large part of my time and force has been abstracted from the purely 

 scientific labors, and for this reason my personal report will be much 

 less elaborate and important than heretofore. 1 trust, however, that the 

 report as a whole will not be surpassed in interest and value by any of 

 the preceding ones. 



My first assistant, Mr. James Stevenson, performed his duties with 

 his nsnal zeal and fidelity. In his management of the Snake Eiver 

 party, he exhibited executive abilities of the highest order. Professor 

 Bradley made some important discoveries in geology. The discovery of 

 an upper member of the Potsdam group will prove an important addi- 

 tion to oiv knowledge of western geology. Among the fossils brought 

 back by Professor Bradley, Mr. Meek has identified the equivalent of 

 the Spergen Hill beds of Indiana, (Saint Louis limestone of the western 

 carboniferous series.) The report of Dr. A. (3. Peale will show his great 

 industry and care. I regard it as one of much importance. W. H. 

 Holmes, as artist, rendered most important services in all departments of 

 the survey. His sections and sketches have proved useful not only for 

 the geological reports, but have been of great value to the topographers 

 in preparing their maps. Mr. William H. Jackson, the photographer, 

 was more successful than in any preceding year. In testimony of the 

 importance of his labors, I quote from a notice of his photographs from 

 the January number of the American Journal of Sciences, by Professor 

 J. D. Dana: 



Next to a personal visit to this land of geysers, hot s^jrings, fountains of boiling 

 mud, waterfalls, lakes, and majestic mountains, is a morning spent over these photo- 

 graphs. They would do credit to the best photographic laboratory, and, considering the 

 difficulties inherent in a long and arduous journey, they are really admirable. The 

 Yellowstone series well illustrates the advantage of photography over auy hand-draw- 

 ings in bringing out details of structure, especially where the artist is guided by the 

 geologist in selecting the best points of view. Among the novelties which are a posi- 

 tive addition to our knowledge of orography we mention particularly the views of the 

 Tiiree Tetons. Among the geyser views there are two of " Old Faithful " in full action 

 which are exceedingly effective ; others of basins and cones in which the varied tracery 

 of the surface may be studied with much of the satisfaction to be had from actual ex- 

 amination ; others, of long cascade slopes which have been gracefully terraced by the 

 mineral depositions of the waters, and whose basins, brimful to their delicate edges 

 with the petrifying waters, reflect mirror-like the surrounding objects ; others showing 

 large areas of the geyser region with the geysers in action. Such views give an oppor- 

 tunity for the geologist to compare beds of chemical deposition with our ordinary 

 limestones. 



Mr. C. Hart Merriam's report will show his zea;l in his special depart- 

 ment. Mr. John M. Coulter acted as botanist, and his report exhits an 

 unusual number of species of plants for a single season's labor. Mr. 

 Walter B. Piatt made interesting collections about the sources of the Yel- 

 lowstone and Missouri Rivers. Tlie plants were added to those of Mr. 

 Coulter, and the birds and mammals to those of Mr. Merriam. The new 



