WILLUMB.J LITTON, WHITE, ROGERS. 157 



but they were not so well acquainted with the Chemung group of New 

 York. This is shown by the fact that Swallow and Meek, in the Mis- 

 souri report of 1885, placed the Chemung above the "Devonian," 1 al- 

 though in tabulating it they bracketed the Chemung with the Devo- 

 nian. However, to the State geologist of New York the "Chemung" 

 was unmistakably Devonian, and for him to correlate deposits in the 

 West with the Chemung necessitated placing them below the Carbon- 

 iferous system ; hence he used the term " Subcarboniferous" to sepa- 

 rate these deposits from the Carboniferous system above, whereas the 

 Western geologists included the Subcarboniferous limestone in the 

 Carboniferous system to distinguish the lower series, which was under 

 the true carbon-bearing Coal Measures. 



Mr. A. Litton 2 in 1860 reported some statistics regarding thickness of 

 deposits derived from a well boring in St. Louis. 



A description of the boring is given, beginning in the St. Louis lime- 

 stoue and penetrating to a depth of 2,199 feet, passing through the 

 limestones, cherty rock, and shales of the Carboniferous system, G50 

 feet, the red marls and the shales of the " Chemung," the limestones, 

 shales, sandstones, etc., of the Hudson River, Trenton, and Black River 

 groups, and finally the magnesian series. The white, soft sandstone 

 found at a depth of 1,505 feet is considered as the Saccharoidal sand- 

 stone; from that the main supply of water was obtained, none rising 

 to the surface from below this sandstone. 



Mr. C. A. White contributed a paper 3 on the rocks at Burlington, 

 Iowa, in 1860, in which he called attention to the close relationship be- 

 tween the faunas in the " Chemung " rocks in the lower part and those 

 in the upper rocks of the Burlington section. He noticed also that the 

 Brachiopods of the " Chemung " were very similar and possibly of 

 identical species in some cases with those above the Burlington lime- 

 stone. He suggested (p. 225-6) that although the so-called Chemung 

 rocks of Iowa may be geologically equivalent to the Chemung of New 

 York they are not contemporaneous ; migration of the species westward 

 having taken place at the close and after the time of the Upper Che- 

 mung of New York. 



W. B. Rogers, commenting upon this paper, 4 remarked on the gradual 

 passage from a Devonian to a Carboniferous fauna on passing west- 

 ward from the Appalachians, previously suggested by James Hall. He 

 suggested that " the mingling of races in successive formations is a nat- 

 ural result of the accumulations of the strata during a long period of 

 comparative repose," and said further: 5 



The changes of fossil faunas are more gradual in proportion to the degree in which 

 the successive deposits of a given period have been preserved from destruction. 



1 See text of the report (vol. 1-2, Pt. 1, p. 101, and Pt. 2, p. 101. 



2 Litton, A.: Belcher & Brothers' artesian well in St. Louis, Missouri. St. Louis Acad. Sci., Trans., 

 1857, vol. 1, 1860, pp. 80-86, plate. 



3 Observations upon the e?oolo#y and paleontology of Burlington, Iowa, and its vicinity, by Charles 

 A. White Sept., I860. Boston Journ. of Nat. Hist. , vol. 2, pp. 209-235. 



4 Proc. Boston Soc. Nat. Hist. , vol. 7, 1861, p. 320. 

 *lbid.,p.321. 



