Mevieics — Hall and Clarke's Palceozoic Brachiopoda, etc. 327 



various systems and their subdivisions, illusti'ated with numerous 

 figures and examples ; while the second to the sixth chapters 

 discuss the relation between a series of crystal faces, the properties 

 of zones and axes, and the nature of crystal symmetry. 



By inverting the order of the chapters, we have here indicated 

 what may be regarded as an objection to the present plan of the 

 book from the point of view of a general reader ; the first six 

 chapters contain much that might with advantage have been 

 postponed to later pages. Subsidiary theorems on stereographic 

 projection, on the transformation of axes, and on tautozonal planes, 

 are not calculated to encourage a beginner, and might well have 

 been deferred to a chapter preceding that on crystal calculation. 

 The chapter on crystalloid symmetry, the most original and 

 interesting in the book, might have been introduced almost at the 

 outset. As it is, the first chapter, on the general characters of 

 crystals, is in parts almost unintelligible to a reader who possesses 

 no knowledge of crystal physics. 



Let the student, however, boldly begin with chapter v, returning 

 to the preceding pages when necessary, and proceed with all possible 

 speed to chapter vii ; and he will find the book a veritable mine of 

 wealth, and one which will repay careful study. 

 - In fact, having stated our objections to the general plan of the 

 book, we may hasten to make reparation by asserting that it is 

 one which if read at all should be read thoroughly ; for example, 

 the great theoretical importance of the equations obtained on page 96 

 will scarcely be appreciated until pp. 112-117 have been mastered. 

 These and the other more difficult parts of the book we may safely 

 commend to the more mathematical reader, to whom they will afford 

 considerable pleasure. 



In most subjects three or four good English text-books exist, and 

 it is sometimes difficult to choose between them. In the science 

 of Crystallography tliere is no such embarrassment. To Professor 

 Maskelyne's book both teacher and student can confidently 1)6 

 referred for two very good reasons : because it has no rival in 

 the English language, and because it is a thoroughly sound and 

 excellent book. A second volume, dealing with the physical 

 properties of crystals, is promised, and will doubtless be expected 

 with interest by geologists, to whom it. should be even more useful 

 than the present volume. 



II. — Thirteenth Annual Report fob the Yeak 1893 of the 



State Geologist. Vol. II: Palaeontology. Transmitted to 



the Legislature of New York, Marcli 1, 1894. One Vol. pp. 



338. Plates 23-54. With Part II of an illustrated " Handbook 



of the Bracbiopoda." By James Hall, assisted by John M. 



Clarke. (James B. Lyon, State Printer, Albany, 1894.) 



rpHIS volume, just received, opens with an instructive summary 



JL of the " Evolution of the Genera of the Palaeozoic Brachiopoda," 



a tabular classification into families, and descriptions of new species. 



These form extracts from the Final Text of vol. viii, part ii, of the 



