Geology and Mineralogy. 65 



tional pages. The labor of the author in thus bringing the vol- 

 ume up to date will be appreciated by a large number of workers 

 in science. 



6. American Permian Vertebrates ; by Samuel W. Willis- 

 ton. Pp. 145 ; 39 plates and many text illustrations. University 

 of Chicago Press, 1911. — In this book Professor Williston brings 

 together "a series of monographic studies, together with briefer 

 notes and descriptions, of new or little-known amphibians and 

 reptiles from the Permian deposits of Texas and New Mexico." 

 He does not think it worth while as yet to " enter extensively 

 into many suggested morphological and taxonomical discussions." 

 We need " more facts, many more facts, and I have little faith in 

 any system of classification based upon our present knowledge of 

 these older land vertebrates." However, certain morphological 

 problems are set forth and what the author regards as " the legiti- 

 mate conclusions regarding the immediate relationships of the 

 forms under discussion " are given. 



The two wonderful graveyards of Permian vertebrates dis- 

 covered by Professor Williston in Texas are described under the 

 captions Cacops Bone-Bed and Craddock Bone-Bed, while some- 

 thing is also added of the Permian locality of New Mexico. 



Many of the animals described in this volume are based on 

 omplete or nearly complete skeletons, and herein lies the greatest 

 value of the book. Then, too, all of the illustrations were made 

 by the author. The orders Temnospondyli, Cotylosauria and 

 Theromorpha are defined, along with eight of their families and 

 seventeen species. c. s. 



7. Analyses of Stone Meteorites ; by O. C. Farrington. 

 Field Museum of Natural History. Publication 151. Geol. 

 Series, vol. iii, No. 9, pp. 195-226. — The author a few years 

 since published a compilation of the analyses of iron meteorites, 

 and he has now accomplished a similar work for stone meteorites. 

 Some one hundred and twenty-five analyses are included, and to 

 them the principles of the Quantitative Classification for terres- 

 trial rocks, with some necessary modifications, have been care- 

 fully applied. It is interesting to quote here the general average 

 arrived at for the composition of stone meteorites, which agrees 

 pretty closely with that earlier obtained by Merrill. 



Average Composition of Stone Meteorites. 



Si0 2 39-12 



A1 2 3 2-62 



Fe 2 3 -38 



Cr 2 3 -41 



FeO __ 16-13 



MnO -18 



NiO -21 



MgO 22-42 



CaO 2-31 



Am. Jour. Sci.— Fourth Series, Vol. XXXIII, No. 193.— January, 1912. 

 5 



