Meviews — H. Carvill Leicis — Glacial Geology. 469 



In the Appendix the author supplies some omissions in the 

 catalogue of the literature previously published, and continues it 

 down to the end of 1893, thus placing the students of fossil sponges 

 under additional obligations. G. J. H. 



II. — Papers and Notes on the Glacial Geology of Great 

 Britain and Ireland. By the late Henry Carvill Lewis, 

 M.A., F.G.S. ; Pi'ofessor of Mineralogy in the Academy of 

 Natural Sciences, Philadelphia, and Professor of Geology in 

 Haverford College, U.S.A. Edited from his unpublished MSS., 

 with an Introduction by Henry W. Crosskey, LL.D., F.G.S. 

 (London and New York : Longmans, Green, and Co. 1894.) 



SCIENTIFIC ideas which engage attention show a remarkable 

 parallelism to the history of chai-acteristic species in a geological 

 formation. Sooner or later, after their first appearance, they attain 

 an extraordinary development, displacing the other ideas or species 

 •which had previously been familiar ; then become less important, 

 and eventually settle down side by side with the older types of life 

 or thought, which often come back again, to share the field with the 

 interloper, which has found its true position. 



The studies of the elder Agassiz among the glaciers of the 

 Alps, gave an impetus to observation of the nature of glaciers and 

 the work they do, which took nearly thirty years to develop. And 

 subsequently the observations of the late Sir Andrew Earasay, and 

 the exposition of Sir Archibald Geikie, led to an endeavour to 

 discover the extent to which the surface of the earth has been 

 shaped by land-ice, which has now reached its full expression. On 

 a recent occasion we drew attention to the way in which Sir William 

 Dawson, preserving the old traditionary iceberg theory of the origin 

 of glacial drift, had endeavoured to apply it in explanation of the 

 glacial phenomena of North America, assigning a subordinate place 

 to the moi'aines produced by terrestrial glaciation. We have now 

 the converse story in the record of observations made by the late 

 Professor Carvill Lewis, on the Glacial Geology of the British 

 Islands. Everyone who knew Mr. Lewis will recognise that no 

 more brilliant exponent of the glacial theory has been heard in the 

 present generation ; and whatever may be the place which his 

 contribution to glacial geology eventually occupies in the history 

 of science, it arrests attention by the boldness of conception which 

 directs it, and by the breadth of observation of fact, which endeavours 

 to apply to this country the mode of interpretation which he had 

 already used in concert with other geologists in the United States. 



The work was, unfortunately, little more than begun, and the 

 memorial volume which we now notice includes but eighty pages of 

 completed papers, and consists largely of the contents of notebooks, 

 which are rather a diary of observations of glacial phenomena as 

 they were seen than a digest, or interpretation. The late Dr. 

 Crosskey has, however, in his introduction, endeavoured to indicate 

 the main points which these extensive and original observations 

 suggest as worthy of examination. Mrs. Lewis contributes a short 



