408 Scientific Intelligence. 



No. 371. Reconnoisance of the Book Cliffs Coal Field between 

 Grand River, Colorado and Sunnyside, Utah ; G. B. Richardson. 

 Pp. 54, 10 plates, 1 figure. 



No. 372. Bibliography of North American Geology for 1906 

 and 1907, with Subject Index ; by F. B. Weeks and J. M. 

 Nickles. Pp. 317. 



No. 376. Peat Deposits of Maine ; by Edson S. Bastin and 

 Charles A. Davis. Prepared in cooperation with the Maine 

 State Survey Commission. Pp. 127, 3 plates, 20 figures. 



No. 378. Results of Purchasing Coal under Government 

 Specifications ; by John Shober Burrows. With a paper on 

 burning the small sizes of anthracite for heat and power pur- 

 poses ; by D wight T. Randall. Pp. 44. 



Water Supply Papers. — No. 221. Geology and Water Re- 

 sources of the Great Falls Region, Montana ; by Cassius A. 

 Fisher. Pp. 89, 7 plates. 



No. 225. Ground Waters of the Indio Region, California, with 

 a sketch of the Colorado Desert ; by Walter C. Mendenhall. 

 Pp. 56, 12 plates, 5 figures. 



No. 226. The Pollution of Streams by Sulphite Pulp Waste. 

 A Study of Possible Remedies ; by Earle Bernard Phelps. 

 Pp. 36. 



Mineral Resources of the United States : 1 907. In two parts. 

 Part I. Metallic Products. Pp. 743, 1 plate, 1 figure. Part II. 

 Nonmetallic Products. Pp. 897, 1 plate, 6 figures. Washington, 

 1908. The several chapters of this important work have already 

 been issued, in advance, in separate forms. 



2. Economic Geology of the Georgetoion Quadrangle, Colo- 

 rado ; by J. E. Spurr and G. H. Garrey ; with General 

 Geology by S. H. Ball. 4°, pp. 422, 87 pis., 155 figs. ; Prof. 

 Paper 63, IT. S. Geol. Survey. Washington, 1908. — While this 

 important work contains an extremely complete study of all the 

 different phases of the geology of the area mentioned in the title, 

 and a very full account of the mineral veins, ores and mines for 

 which the district is noted, and thus presents a great mass of 

 material which it would be impossible to adequately review in a 

 brief notice, probably that feature of the work which is of most 

 importance and general interest concerns the conclusions regard- 

 ing the genesis of the ore bodies to which the authors have been 

 led as the result of their studies. 



Besides the sedimentary formations in the area which have 

 been metamorphosed into gneisses and schists, the great bulk of 

 the rocks are of igneous origin, intrusive in occurrence and due 

 to successive upthrusts of different magmas mostly in pre-Cam- 

 brian, but some in Tertiary, times. The older these rocks are 

 the more gneissoid is the structure which they exhibit. They 

 vary from granites through monzonites to diorites. They are 

 cut by aplites and pegmatites and by later dikes and masses of 

 porphyry, bostonite, syenite, etc. In general, later than the 

 intrusion of these porphyries, etc., occurred the formation of 

 veins by deposition along fault fissures, which were also later in 



