Geology and Mineralogy. 71 



development of a very extensive industry, an end which will be 

 materially stimulated by the present volume. 



The various types of rocks, from the granites to the sandstones 

 and quartzites, are described in detail and an account is also given 

 of the quarries in actual operation. Under the marbles some 

 new localities are mentioned, and one marble of special interest 

 is described from Mitchell County ; this is pure white in color 

 and suitable for those purposes for which the finest grades of 

 marble are required. Some stones of peculiar interest in the 

 State are the quartz porphyry or leopardite, found in Mecklen- 

 burg County, and the orbicular-gabbro diorite, found in Davis 

 County. Both of these are attractive stones for monumental 

 purposes. Another unusual rock is the variety of granite known 

 as unakite, composed of yellow-green epidote, dull pink or red 

 feldspar and quartz. 



The concluding chapters describe the methods of quarrying, 

 the weathering of building stones and the rocks suitable for road 

 building. 



10. Clays: Their Occurrence, Properties and Uses with especial 

 reference to those of the United States • by Heinrich Ries. Pp. 

 xiv, 490, with 44 plates and 65 figures. New York, 1906 (John 

 Wiley & Sons). — The author of this volume has already made 

 extensive studies of the clays and clay industries in the United 

 States, in connection with the U. S. Geological Survey and also 

 the Surveys of Maryland and New Jersey. He has now ren- 

 dered a great service not only to geologists and chemists, but 

 also to those commercially interested, by bringing together 

 within the limits of a single volume all that is most important 

 in relation to this subject. The book opens with a brief state- 

 ment in regard to the origin of clay beds, and then goes on to 

 discuss in detail the chemical and physical properties and the' 

 different types of clays useful for different purposes. The last 

 half of the book is given to an account of the distribution of 

 clay at the many localities at which it occurs in the different 

 states, the facts being arranged conveniently according to the 

 geological formations. This latter portion of the work is liber- 

 ally illustrated with many reproductions from photographs, 

 which add much to the value of the descriptions. 



11. Palozozoic Fossils, Vol. Ill, Part IV : by J. F. Whiteaves. 

 Geol. Surv. Canada, 1906, ,pp. 243-352, pis. xxiii-xlii. — This 

 part concludes the third volume of Paleozoic Fossils begun by 

 Billings in 1861, and consists of four papers, as follows : — 



5. The Fossils of the Silurian (Upper Silurian) rocks of Kee- 

 watin, Manitoba, the northeastern shore of Lake Winnepegosis, 

 and the lower Saskatchewan River. 



6. The Canadian species of Plectoceras and Barrandeoceras. 

 1. Illustrations of seven species of fossils from the Cambrian, 



Cambro-Silurian, and Devonian rocks of Canada. 



8. Revised list of the fossils of the Guelph formation of 

 Ontario. With appendix, consisting of a list of errata, and an 

 index to the volume. c. s. 



