Geology. 235 



If these conditions should exist, we would have the outer por- 

 tion of the crust so plastic that the differences in elevation now 

 existing would very quickly flatten out. It implies no rigidity 

 whatever to the earth's outer material, which idea we cannot 

 accept. Besi des, the movement, according to Tandy 's views, would 

 be from a column with a surface of low elevation to a column with 

 a surface much higher. Unless the transfer of matter takes 

 place at or near the depth of compensation we should have matter 

 flowing against stress differences, which is impossible. It is not 

 conceivable that each small column with a cross section not 

 greater than the area of a small mountain valley or a hillside is, 

 independently, in isostatic equilibrium. It is impossible that 

 each small feature is independently compensated, for, should this 

 be true, there would have to be an almost total lack of friction 

 between the small columns of the isostatic shell. It is true that 

 in making the computations for the effect of isostatic compensa- 

 tion we assume complete local isostasy, but this must be done to 

 facilitate the operations. 



I strongly recommend to the student of the earth's crust that 

 he read and study Col. Tandy's paper. Some of it is sound; 

 other parts seem to me weak, but the author must be looked upon 

 as a crusader in the field of geology, fighting some theories which 

 are generally accepted but which are not in accord with the 

 accumulated geodetic and geophysical data. Like the crusader, 

 he lets his feelings, at times, warp his judgment. 



V7ILLIAM BOWIE. 



2. A Reprint of the more inaccessible paleontological Writ- 

 ings of Robert John Lechmere Guppy; by G. D. Harris. Bull. 

 Amer. Paleontology, No. 35, 198 pp., 10 pis. a,nd portrait, 1921. — ■ 

 Illustrations and Descriptions of fossil Mollnsca contained in the 

 Paleontological Collections at Cornell University ; by Katherine 

 E. H. Van Winkle. Ibid., No. 36, 12 pp., 1 pi., 1^21.— New Eocene 

 Species from Alabama; by T. H. Aldrich. Ibid., No. 37, 32 pp., 

 3 pis., 1921. — Of the forty-two more important paleontological 

 papers written by Rev. Robert J. L. Guppy and relating to West 

 Indian Cenozoic fossils, twenty -five are here reprinted in Bulletin 

 35. The remainder were published in well known journals and 

 are accessible to most paleontologists, but those here reprinted 

 were originally printed in obscure places and so were no longer 

 obtainable. In Bulletin 36, Miss Van Winkle describes a small 

 number of new and old Cenozoic species in the Cornell collections, 

 and in Bulletin 37, Mr. Aldrich describes fifty-three species, of 

 which nearly all are new. c. s. 



3. Grilndziige der Paldontologie (Paldozoologie) ; by Karl 

 A. VON ZiTTEL^ reworked by F. Broili. I. Abteilung, Invertebrata, 



Am. Jour. Sci.— Fifth Series, Vol. II, No. 10.— October, 1931. 

 16 



