210 THE DEVONIAN AND CARBONIFEROUS. |bull.80. 



modifications more characteristic of the true Permian faunas of Europe. 1 

 In regard to the conditions of deposition, he interpreted the series as 

 follows: 2 Marine limestones indicate lowest depression ; coal beds were 

 formed during the greatest elevation, and the condition of Millstone 

 grit and the newer coal formations was intermediate between these two. 

 Tidal currents were recognized in the Carboniferous, cutting out chan- 

 nels called " tidal channels." 3 The author also recognized that Devonian 

 and Silurian rocks were above the water during the deposition of the 

 rocks of the Goal Measures of Nova Scotia, so that the coal deposits 

 are more or less separated from each other. 



The flora was regarded as identical throughout the whole Middle 

 Coal Measures, and the Lower, Middle, and Upper may be distinguished 

 by their plants. Dawson also held that the flora of the Lower Coal 

 Measures of Nova Scotia is wholly Carboniferous, and that the flora of 

 the Chemung, Vergent, and Ponent, IX and X, of Lesley, is decidedly 

 Devonian. 



The author recognized, not 25,000 feet for Nova Scotia Coal Measures, 

 but Logan's measure of 15,570 feet for the Jogging, and for the Middle 

 Coal Measures, 1,000. He mentioned the fact that in England it is the 

 usage to apply the term Lower Coal Measures to the lower part of what 

 he called the Middle Coal formation, that is, above the Millstone grit. 

 He quoted Geinitz in identifying the divisions of the coal formations 

 by plants. His Lower Coal formation is the Lycopodiaceous Zone or 

 Culm of Europe; his Middle Coal formation is the Sigillaria and Stig- 

 maria Zone; the Upper Coal formation is the Zone of Calamites of 

 Geinitz. 



Mr. C. A. White wrote in 1874 that Dr. L. G. De Koninck had identi- 

 fied many of the species from the Coal Measures of Springfield, Illinois, 

 with Lower Carboniferous species of Europe, and Geinitz had identified 

 species found in the Upper Carboniferous of Nebraska as Permian. 

 The mingling of faunas thus indicated, the author held, is due to the 

 fact that while the region in which true Coal Measures were being 

 deposited were little invaded by the seas during the whole Carbonifer- 

 ous period, America was occupied in some places by the sea, which fact 

 accounts for the wide distribution of marine faunas as compared with 

 those of Europe. Chronological development is also proved by the 

 similarity of the floras of the two countries, as has been pointed out 

 by Dr. Newberry and Mr. Lesquereux. 



The next four papers give additional information upon the Permian 

 and Per mo-Carboniferous formations of Kansas and Nebraska. 4 



Coal belonging to the Lower Coal Measures is found in marketable 

 quantities in Osage County. It is well exposed on the southern side 

 of Neosho Valley, running through Miami County. Upper Coal Meas : 



1 Pp. 283-285. 



2 P. 133. 



3 P. 125. 



4 Broadhead, Gr. C. : The Carboniferous rocks of southeastern Kansas. Am. Jour. Sci., 3d ser., 188J, 

 vol. 22, pp. 55-57. 



