Revieifs — Professor LapicortJi's Textboolc of Geology. 87 



over with volcanic cones ! A novel explanation of tlie origin of 

 the clayey partings or division planes in limestones is, that they 

 arise from the action of earthquakes which result in shaking up the 

 fine silt of the bottom of the ocean and produce a mud which is 

 fatal to the breathing organs of the animals living on the sea-floor, 

 and consequently the materials of these shaly layers are mostly 

 inorganic ! 



Though Professor Shaler's work is, perhaps, more especially 

 adapted for the scientific public of the United States, it nevertheless 

 contains much that deserves the attention and consideration of 

 geological students generally. 



IV. — A Student's Textbook. 



An Intermediate Textbook of Geology. By Professor Charles 

 Lapworth, P.R.S. Founded on the " Introductory Textbook of 

 Geology " by the late David Page. pp. 414, with 174 Illustrations. 

 (London : William Blackwood & Sons, 1899.) 



NGLISH teachers of Geology are to be congratulated upon the 

 issue of a new edition of Professor Lapvvorth's revision of 

 Page's "Introductory Textbook." The book is an even greater 

 improvement on the 12th edition than that was on its predecessors. 

 The new issue is better illustrated ; some unfortunate misprints and 

 errors which slipped into the pages of the 1888 edition have been 

 removed; the paleeontological nomenclature is more modern; and 

 the book is so much larger that it well deserves its new title of an 

 " Intermediate Textbook of Geology." The work as it now stands 

 is essentially a British student's textbook, and for students after 

 their first year's course it seems to us quite indispensable. 



The most remarkable feature in the book is that it is crowded but 

 clear. The information is very condensed, but the main outlines 

 are graphic. Professor Lapworth shows his unusual power of 

 making every subject appear real with detail, while the main idea 

 stands out with the clearness of a diagram. 



The account of British geology is illustrated by a series of new 

 and lucid maps, each showing the range of one system and the areas 

 of early and later formations. The stratigraphical section is 

 naturally the best, and is well up to date. Eegarding it we have 

 only one regret. Professor Lapvvorth's systematic self-suppression. 

 One naturally expects to learn his opinion on disputed questions ; 

 and as a rule one has to read between the lines. For the author 

 is careful not to encourage students to abandon orthodox belie Is too 

 readily, and his own opinions have to be guessed from the insertion 

 of such reserving clauses as " have been regarded," " is supposed 

 to have been," or " it is held by some." Most geologists would 

 probably have preferred the book to have definitely told us what 

 Professor Lapworth himself regards, supposes, or holds in reference 

 to the main disputed problems. 



A feature in the new edition which is especially worthy of notice 

 is the series of masterly sketches of foreign geology ; they are 



