REVIEWS. . 747 



tant is the recognition of the complexity and the protracted character 

 of the glacial period as a whole. Until this is recognized, it will be 

 difficult to prosecute work intelligently along the lines which must ulti- 

 mately determine whether the rank of the several subdivisions is epochal 

 or episodal. 



A single word may be added with reference to Professor Geikie's 

 chapter concerning the " Cause of the Glacial Climate." It has already 

 been noted that the discussion of this subject has been relegated to the 

 last chapter of the volume. In the course of this discussion it is evident 

 that Professor Geikie holds much less strongly than heretofore to 

 Croll's hypothesis of glacial climate. While he indicates that this 

 hypothesis probably "contains a large element of truth" he does not 

 regard it as a full solution of the vexed question. He further indicates 

 that the complex phenomena of Europe "are evidence of a succession 

 of changes too manifold, and perhaps occupying too short a space of 

 time, to be accounted for by the cause to which Croll appealed." Pro- 

 fessor Geikie's attitude seems to be well expressed in one of his closing 

 sentences : "The primary cause of those remarkable changes is thus an 

 extremely perplexing question, and it must be confessed that a complete 

 solution of the problem has not yet been found." 



Rollin D. Salisbury. 



Papers and Notes on the Glacial Geology of Great Britai?i a?id Ireland. 



By the late Henry Carvill Lewis. Edited from his 



unpublished MSS., with an introduction, by Henry W. 



Crosskey. Pp. lxxxi + 469. Maps x., figures 83. London: 



Longmans, Green & Co., 1894. 

 Dr. Crosskey and the devoted wife of the late Professor Henry 

 Carvill Lewis have placed all who are interested in glacial phenomena 

 under lasting obligations by the publication, in elegant form, of the 

 papers and notes of one who was among the most active and enthusi- 

 astic of American glacialists. It would have been a pleasure to the 

 writer to have made earlier notice of this work, had not his absence 

 from the country prevented. The book embraces papers on (1) Com- 

 parative Studies upon the Glaciation of North America, Great 

 Britain and Ireland; (2) The Terminal Moraines of the Great Glaciers 

 of England ; (3) On some Important Extra-Morainic Lakes in Central 

 England, North America, and elsewhere, during the period of maxi- 



