236 JOURNAL. OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO 10 



Repeated submergence and emergence has been the dominant factor in the 

 development of the physiographic features of the coastal belt. These fea- 

 tures comprise several extensive and numerous small sea terraces, ranging in 

 elevation from 2() to 1200 feet above sea level, and dissected by streams to 

 depths as much as 200 feet below the present sea level. The major valleys 

 in the coastal belt have wide, flat, gently sloping floors, bordered by very 

 steep slopes or bluffs several hundred feet high. They contain deposits of 

 valley fill as much as 200 feet in depth. 



The geologic formations exposed in the highland comprise igneous and 

 metamorphic rocks most of which are considered to be post-Carboniferous 

 and not younger than early Cretaceous. Thick deposits of Quaternary 

 alluvium occupy parts of the principal river valleys. In the coastal belt, 

 sedimentary formations ranging in age from Cretaceous to Recent are ex- 

 posed. Undifferentiated Miocene and Pliocene deposits, parts of which have 

 been referred to in earlier literature as the vSan Diego beds, are designated 

 as the San Diego formation. 



The portion of this report prepared by Charles H. Lee treats of the ground- 

 water hydrology of the shallow water-bearing formations of the Pacific vSlope 

 of the county, and the utilization of ground water from these formations 

 Complete precipitation records at 106 stations and a detailed map are pre- 

 sented. Conclusions are drawn regarding the amount of rainfall in any season 

 necessary to produce run-off and also the relation of rainfall to run-off. 

 Evaporation observations are given and comparison made between evapo- 

 ration from a pan floating on a large reservoir surface, and the reservoir 

 surface itself, which indicate that there is little difference between the two . 

 Data r egarding soil evaporation and transpiration from mixed natural 

 vegetation are also given. 



Detailed physical descriptions are given of the largest ten underground 

 reservoirs of the region lying in the principal river valleys, with detailed 

 geological and other data. The conclusion is drawn that ground water in 

 the San Diego County river valleys has very Uttle movement and seldom 

 occurs as underground streams, but occupies underground reservoirs. Sim- 

 ilar data are also presented for other underground reservoirs of the region. 



Tests of existing pumping plants of various types are presented, which, for 

 working conditions on the farm, show pump and pumping-plant efficiency 

 and cost of pumping for inigation. The selection and installation of pumping 

 machinery are also discussed. A. J. E. and C. H. L. 



GEOLOGY. — The origin of the faults, anticlines, and buried "Granite Ridge" 

 of the northern part of Mid-Continent oil and gas field. A. E. Fath. 

 U. S. Geol. Survey Prof. Paper 128-C. Pp. 10 (75-84), pis. 3, figs. 3. 

 1920. 



The paper is an attempt to find a common cause for the more or less parallel 

 or continuous alinement in a general N.-NE. direction of the buried "granite 

 ridge" of Kansas, certain larger folds, and a line of en echelon faults in Okla- 

 homa and Kansas. Beginning with the discussion of the belts of faults the 

 author assumes that the Pennsylvania strata would be incompetent to trans- 

 mit the stresses which produced the faults but that the deeper-lying rocks from 

 the Mississippian limestones down into the pre-Cambrian would be. He 

 shows that horizontal movement along deep -lying faults coinciding in position 

 and direction with the belts of en echelon surface faults could produce them. 

 He also shows that folds and lines of folds might result from vertical move- 



