a Te ee eh ee 
Geology and Natural History. 479 
here is nothing in the working hypothesis of Prof. Henry which 
excludes any truth there may be in the working hypothesis of 
14, A new Treatise on Elements of Mechanies, establishing strict 
HN 
W. Nysrrom, C.E. 352 pp- 8vo. Philadelphia, 1875. (Porter 
& Coates. )—This volume contains a great number of problems in 
practical mechanics, with concise and excellent solutions, and 
Some useful tables. The author makes some innovations in the 
technical language of the science, which are not likely to be con- 
Sidered as in all respects improvements, and some of the topics 
treated in the volume are rather irrelevant to the subject. A. Ww. 
Il. Gooey anp Naturau Hisrory. 
_ |: Primordial fossils in pebbles of the Newport (Rhode Island} 
.—Prof. Wm. B. Roars, in the Proceedings of th 
origin of the flattened form of the siliceous pebbles or stones of 
*. Bowlder near Batavia, Genesee County, New York.—The 
bowlder “on the road from Caledonia to Batavia,” figure 
