SOME NEW BOOKS. 



Professor Prestwich on Some Geological Problems. 



Collected Papers on some Controverted Questions of Geology. By 

 Joseph Prestwich, D.C.L., F.R.S., etc. 8vo. Pp. xi.-ayg, with 13 plates and 

 8 figures. Macmillan & Co. 1895. Price los. net. 



As Professor Prestwich is the acknowledged doyen of British 

 geology, his opinions are entitled to the most respectful consideration. 

 He always brings to any discussion a judgment resulting from an 

 unusually long experience, and his writings have always shown that 

 he is especially apt at preparing judicial statements of the arguments 

 on both sides of the vexed questions of geology. One, therefore, 

 turns to the volume expecting important help in defining and 

 limiting the issues of current geological controversy. It is, therefore, 

 rather a disappointment to find that the book consists of reprints. 

 But as the articles have been revised and sometimes enlarged, a 

 series of plates added, and the papers collected from scattered 

 sources, the volume must be heartily welcomed, both as conveying 

 fresh information and giving some of Professor Prestwich's latest 

 conclusions in a convenient form. 



The book contains six articles. These deal with " Uniformi- 

 tarianism," " The Date and Duration of the Ice Age," " Plateau 

 Man in Kent," "The Agency of Water in Volcanic Eruptions," 

 " The Thickness of the Earth's Crust," and " The Rate of Rise ot 

 Underground Temperatures." The first of these is a reprint from 

 the Nineteenth Century, and contains a protest against accepting the 

 positive conclusions of physicists as to the rigidity of the earth, or 

 the exaggerated estimates of geologists as to the length of time 

 required for certain geological operations. Professor Prestwich 

 strongly objects to what he calls " the Fetich of uniformity " ; he 

 states the views of some of the most devoted worshippers, as if they 

 were those of the orthodox members of this school. He quotes 

 Croll, and accepts him apparently as a typical representative of the 

 Uniformitarians, although his theories have long since fallen from 

 the prominent position which they once held. With Professor 

 Prestwich's criticisms upon these views we heartily agree, though 

 without in any way losing faith in the uniformity of geological 

 phenomena. Professor Prestwich fully admits that the forces of 

 erosion and the modes of sedimentation are "the same in kind as 

 they have ever been ; but we can never admit that they have always 

 been the same in degree " (p. 14). With this probably every unifor- 

 mitarian would agree : differences in degree must have happened ; 

 rainfalls vary, climates alter, and ocean currents gain or lose in 

 erosive power by simple changes such as we can see going on around 

 us at present. No one can set a limit to these changes ; they appear 

 to us to vitiate every attempt to calculate geological time in terms of 

 years. And we are sorry to have to confess that, when Professor 



