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REVIEWS 



Hershey, Oscar H. The Quaternary of Southern California. Bull. Dept. 

 Geol. Univ. Calif., Vol. Ill, pp. 1-30, 1902. 



The paper discusses the orographic disturbances in the early part of the Quater- 

 nary which lifted upper Pliocene beds to altitudes several thousand feet above the sea. 

 A provisional scheme of classification is then brought out, which is expressed in the 

 table below. The last column represents mere suspicions as to relative lengths of the 

 different epochs. 



TABLE OF QUATERNARY CONDITIONS. 



Hershey, Oscar H. The Term Sierran. Am. Geol., Vol. XXIX, pp. 88-05, 

 1902. 



It is considered doubtful if the contemporaneity of uplift on the Pacific coast with 

 that m the eastern part of the United States has evidence to amount to a demonstra- 

 tion. For this reason it seems premature to attempt to correlate erosion cycles on 

 opposite sides of the continent. The Sierran valleys cannot be directly compared 

 with the Ozarkian valleys of the Mississippi basin. It appears highly probable that 

 the Sierran excavatien on the Pacific coast began before the opening of the Glacial 

 epoch of the eastern states and was contemporaneous in part with the Ozarkian. But 

 it is still in progress and was only slightly affected by glaciation in the high Sierra 

 Under LeConte's definition Sierran covers, apparently at least, part of the Ozarkian and 

 nearly all of the Glacial epoch. The so-called Glacial epoch of the California moun- 

 tains was probably one-twentieth or one-fiftieth of the Glacial epoch of the eastern 

 part of the United States. The author does not attempt to use "Ozarkian" on the 

 Pacific coast, nor "Sierran" in the interior of the United States. 



HiLGARD, E. W. The Debris Fajts of the Arid Regiojts in their Relation to 

 Water Supply. Abstract, Science, N. S., Vol. XV, p. 414, 1902. 

 The structure of the debris fans is described and the value of these fans in form- 

 ing natural storage and regulating reservoirs for water is brought out. 



HiLGARD, E. W. A Sketch of the Pedalogical Geology of California. Abstract, 

 Jour. Geol., Vol. IX, pp. 74, 75, 1901; also Bull. Geol. Soc. Amer., Vol. 

 XII, pp. 499-500, 1901. 



The paper discusses the soil conditions, including also the difference between 

 rock decomposition in arid and humid climates. In the humid regions loams and clay 

 soils are produced, while in aiid regions the soils are sandy and dusty unless derived 

 from pre-existing clay formations which give rise to "adobe." In the arid regions 

 there is a uniform soil mass to a depth of four to ten feet, with practically no subsoil. 



