REVIEWS 291 



of Oil Wells and Gas Wells — Gas Pressure" (pp. 180-98), and "Chemical 

 Conditions of Oil and Gas" (pp. 199-227). The second of these three chap- 

 ters also includes an abstract of a paper by Dr. C. Engler on the "Origin 

 of Petroleum" (pp. i98a-i98c?). Chap, vii, comprising pp. 228-302, was 

 written by H. P. Cady and D. F. McFarland and deals with the chemical 

 composition of gas, as the following chapter by F. W. Bushong deals with 

 the chemical composition of petroleum (pp. 303-17). The title of the 

 ninth chapter is "Coal-Measure Faunal Studies," by J. W. Beede and 

 A. F. Rogers, and it comprises pp. 318-85. The last two articles were 

 written by E. H. Sellards, who deals with "Fossil Plants of the Kansas 

 Upper Paleozoic" (pp. 386-500), and "Fossil Cockroaches in the Kansas 

 Coal Measures and Kansas Permian" (pp. 501-41). 



The one of these papers which the writer's studies permit him to dis- 

 cuss most intelligently is that by Beede and Rogers on the Faunal divisions 

 of the Kansas Coal Measures. This is a subject well worthy of investigation 

 for if correlations are to be made with the Kansas section, it will probably 

 be more with groups than with individual formations, some of which are 

 only a few feet in thickness. Previous groupings of the formations had been 

 suggested by authors, partly on considerations of stratigraphy, partly, as 

 in Prosser's stages proposed for divisions in the upper portion of the section, 

 on paleontologic evidence, but nothing which was as comprehensive and 

 consistent involving the formations of the. entire series and based on such 

 an accumulation of data. In this connection it seems unfortunate that the 

 classification and nomenclature of Beede and Rogers, resting it would 

 appear especially on paleontological evidence, does not agree with that of 

 Haworth and Bennett in the same volume, which appears to have sprung 

 from considerations of lithology, topography, etc. Although I have myself 

 studied the Kansas faunal sequence in a somewhat incidental and dilettante 

 manner, I am not prepared with any criticism of the validity of the groups 

 proposed. These will stand or fall as they meet the test of experience, 

 but the authors certainly know the Kansas section better than any other 

 paleontologists and there is no reason to doubt that their classification is, 

 taken all in all, the best that has been proposed. 



It seems rather doubtful, however, after reading their paper, whether 

 the Kansas section can be used as a reference section with any degree of 

 advantage. The authors find such variations in the faunas collected at 

 different points in certain of the formations that were it not for their strati- 

 graphic connection they would hardly be believed to be the same horizon. 

 In my own work on the Kansas faunas similar anomalies were observed 

 which led me to suspect the correctness with which the beds had been traced. 



