Geology and Mineralogy. 503 



The monograph is a statement of facts, and all of the species 

 are illustrated, making the work an easily usable one of refer- 

 ence for the Pottsville fauna of Ohio. It is a pleasure to note 

 so promising an initial contribution from a new woman worker 

 in Paleontology. c. s. 



2. Earth and Sun: An Hypothesis of Weather and Sunspots 

 (in press). Climatic Changes, their Nature and Causes, by 

 Ellsworth Huntington and Stephen S. Visher. New 

 Haven (Yale University Press), 329 pp., 13 text figs., 10 tables, 

 1922. — The first volume treats of the causes of weather, and is 

 introductory to the second, more philosophical one on climatic 

 changes, past and present. The underlying theme is the senior- 

 author's " solar cyclonic hypothesis," which holds, briefly, that 

 "the changing temperature of the sun," as revealed in sunspots, 

 alters the storminess and temperature of the earth, and that 

 these factors, along with those of a changing earth's surface, 

 bring about the climatic changes on the earth. It is a most 

 interesting, very intricate, and far-reaching hypothesis, and one 

 that weaves all Nature into a web of consequences. The theory 

 is not only presented fully in ''Climatic Changes," but in a 

 style easily readable. 



The first main hypothesis is ' ' that the earth 's present climatic 

 variations are correlated with changes in the solar atmosphere. 

 This is the key-note of the whole book" (311). 



The second main hypothesis is "that variations in the solar 

 atmosphere influence the earth's climate chiefly by causing vari- 

 ations not only in temperature but also in atmospheric pressure 

 and thus in storminess, wind, and rainfall" (312). 



The above two causes are balanced in that "many climatic 

 conditions are due to purely terrestrial causes, such as the form 

 and altitude of the lands, the degree to which the continents 

 are united, the movement of ocean currents, the activity of 

 volcanoes, and the composition of the atmosphere and the ocean. 

 Onlv bv combining the solar and the terrestrial can the truth be 

 perceived" (312). 



"Finally, the last main hypothesis, . . .holds that if the cli- 

 matic conditions which now prevail at times of solar activity 

 were magnified sufficiently and if they occurred in conjunction 

 with certain important terrestrial conditions of which there is 

 good evidence, they would produce most of the notable phe- 

 nomena of glacial periods" (312). c. s. 



3. Seventeenth Report of the Director of the New York 

 State Museum and Science Department : N. Y. State Mus., Bulls. 

 239-240, 209 pp., pis., maps, and text figs., 1922. — The head of 

 this great state museum, Doctor John M. Clarke, describes here 

 in an interesting way the work of its various departments during 

 the year 1920-1921. "We are glad to note the accession of a 



