472 abstracts: geology 



is given to an outline of the extent and character of each of the drift 

 sheets, the loess, and the alluvium. The detailed descriptions then 

 follow, county by county, and under each county appear tables show- 

 ing the percentages of each class of land, and farm and crop data, 

 the latter being taken from the reports of the Federal Census of 1910. 

 The percentage of improved land ranges from about 7 per cent in Pine 

 and Crow Wing Counties to over 80 per cent in each of a dozen counties in 

 the south end of the State. The relatively stony red drift of the north- 

 eastern part of this area, with its cover of forest and brush, is less at- 

 tractive to the farmer than the more clayey gray drift of the remainder 

 of the area which is largely in prairie or oak openings. Consequently 

 the red drift has correspondingly slight development. The extent of 

 swamp land is shown for each county, and is found to be much greater 

 in the forested than in the prairie counties. A small map is included 

 to show the distribution of forest and prairie. F. L. 



GEOLOGY. — Nickel deposits in the lower Copper River Valley, Alaska. 

 R. M. OvERBECK. U. S. Geol. Survey BuU. 712-C. Pp. 8 (91-98). 

 1919. 



Nickel deposits have been found in the valley of Canyon Creek, a 

 small stream that enters Copper River 6 miles below the mouth of 

 Chitina River. The country rock is light-gray limy and quartzose 

 schist, into which peridotite has been intruded. The peridotite is rather 

 strongly mineralized in places with sulfides, with which the nickel is 

 associated. The peridotite is highly altered and coarse grained. 16 

 nickel claims have been located, but very little development work has 

 been done. At present, the known nickel deposits of Alaska probably 

 could not compete on the basis of nickel content alone, with the de- 

 posits of Sudbury, Canada. R. W. Stone. 



GEOLOGY AND HYDROLOGY.— 6^wmwc/ water in the San Jacinto 

 and Temecula Basins, California. Gerald A. Waring. U. S. 

 Geol. Survey Water-Supply Paper 429. Pp. 113, pis. 14, figs. 

 15. 1919. 



Observations on the ground- water level during 1904-1916 are given, 

 with mention of the relation of the changes in level to rainfall and to 

 irrigation development. Areas of flowing artesian wells are outlined, 

 and the possibility of obtaining flows in other localities discussed. 

 Analyses of well waters are given, with a discussion of their use and 

 adaptability for irrigation. A map (PI. Ill), shows the general geology 



