226 Scientific Intelligence. 



2. Publications of the United States Geological Survey/ 

 Charles D. Walcott, Director. — The recent publications of the 

 Survey are noted in the following list (continued from p. 65) : 



Twenty-seventh Annual Report of the Director of the United 

 States Geological Survey to the Secretary of the Interior 1905-6. 

 Pp. 104, with 24 plates. See p. 225. 



Monograph Volume L. The Cretaceous Flora of Southern 

 New York and New England ; by Arthur Hollick. Pp. 219, 

 with 40 plates, and numerous figures. See p. 233. 



Folio No. 142. Geologic Atlas of the United States. Cloud 

 Peak — Fort Mc Kinney Folio, Wyoming. Description of Cloud 

 Peak and Fort McKinney Quadrangles ; by N. H. Darton : 

 Glacial Geology by R. D. Salisbury. Pp. 16, with 7 colored 

 maps and 21 figures. 



Professional Paper, No. 52. Geology and Underground 

 Waters of the Arkansas Valley in Eastern Colorado ; by N. H. 

 Darton. Pp. 90, with 27 plates and 2 figures. — See p. 149, Feb., 

 1907. 



Bulletins, No. 302. The Areas of the United States, the 

 States, and the Territories; by Henry Gannett. Pp. 9 with 

 colored map. 



No. 306. Rate of Recession of Niagara Falls ; by G. K. 

 Gilbert, accompanied by a Report on the Survey of the Crest ; 

 by W. Cartel Hall. Pp. 31, with 11 plates and 8 figures. 



No. 307. Manual of Topographic Methods; by Henry Gan- 

 nett. Pp. 86, with 8 plates and 4 figures. 



No. 310. Results of Primary Triangulation and Primary 

 Traverse, Fiscal year 1905-6; by Samuel S. Gannett. Pp. 

 xiii, 248, with one plate. 



Water Supply and Irrigation - Papers, No. 189. The Pre- 

 vention of Stream Pollution by Strawboard Waste ; by Earle 

 Bernard Phelps. Pp. 29, with 2 plates and 2 figures. 



Mineral Resources of the United States ; Calendar year 1905, 

 David T. Day, Chief of Division of Mining and Mineral Re- 

 sources. Various advance chapters from this work have been 

 issued. These include, among others, the following : 



The Production of Gold and Silver in 1905 ; by Waldemar 

 Lindgren and others. Pp. 1-229. 



Total Output and Value by States of the Mineral Products of 

 the United States in 1905 ; compiled by Wi. Taylor Thom. 

 Pp. 15-30. 



3. Hate of Recession of Niagara Falls ; by G. K. Gilbert, 

 accompanied by a report on the survey of the crest, by W. Carvel 

 Hall. Bull. No. 306, U. S. Geological Survey. Washington, 

 19o7. Pp. 31, pis. 11, figs. 8. — In this bulletin it is pointed out 

 that the present is a time of transition from natural to more or 

 less artificial conditions in the flow and consequently the recession 

 of Niagara Falls. For this reason an accurate survey of the 

 crest-line was ordered in. 1905 and this bulletin incorporates the 

 data thus obtained into the discussion on the rate of recession. 



