178 THE DEVONIAN AND CARBONIFEROUS. |dull.80. 



sandstones were called the "Napoleon group 17 and the lower the "Mar- 

 shall group. 77 Mr. Winchell traced the course of the outcrops of these 

 groups to the northeast and west and spoke of their being overlaid by 

 the Michigan Salt group at Grand Rapids and vicinity and underlaid in 

 the southwestern couuties by a considerable thickness of argillaceous 

 strata. In Huron County the "Huron group 77 of gritstone, green shales, 

 and bituminous shales is found beneath the Marshall sandstone, and 

 farther north the Hamilton limestones precede this group. 



The descriptions of supposed new Cephalopods comprise ten species of 

 Orthoceras, seven of Nautilus, one of Oyrtoceras, and eight of Goniatites. 



In a paper 1 published in 1863 Mr. Winchell stated his conviction that 

 a comparison establishes "fully the equivalency of the Chemung, Mar- 

 shall, Ohio [i. e., Waverly], Rockford [i. e., Goniatite limestone], Bur- 

 lington [i. e., Kinderhook], and Chouteau strata." 2 



Further investigation modified this conviction, as we shall see beyond. 



In 18G4 appeared another paper. 3 This was devoted to a description 

 of certain western rocks near the line between the Devonian and Car- 

 boniferous systems and their contained faunas. "The paper shows an 

 extended net-work of identification among the fossils from States west 

 of Pennsylvania." The author identifies also " four western species with 

 those in the supposed Carboniferous conglomerate of western New 

 York," two of which species are regarded as being at the top of Chemung 

 rocks of western New York. He inclined to the view that since there 

 appears no close resemblance between the Chemung of New York and 

 western rocks, the "Carboniferous conglomerate" of western New York 

 may be the eastern prolongation of the western sandstones and shales, 

 at least of the fossiliferous portions of them, and that the Chemung of 

 New York must be classed with the Devonian rocks. " Ninety-four 

 species are described in this paper, of which thirty-six are described as 

 new species, and two are made the types of new genera." This brief 

 outline is followed by descriptions of the species. 



The view that the so-called "Chemung" of the States west of New 

 York should be correlated with the "Carboniferous conglomerate" 

 system was expressed by Meek and Worthen in 1861. 4 



In 1870 Winchell completed his studies of the correlation of the Mar- 

 shall group, 5 and published an elaborate memoir upon the subject. In 

 the appendix are cited ninety papers on the geology of the rocks under 

 consideration. He opened the paper by a reference to the " controversy 

 which has long existed in reference to the age and equivalents of the 

 strata lying between the Corniferous limestone and the limestone of the 



'Winchell, Alexander, on the identification of the Catskill Red Sandstone group with the Chemung. 

 Am. Jour. Sci., 2d ser., vol. 35, 1863, pp. 61-62. 



2 Ibid., p. 62. 



8 Descriptions of new species of fossils from the Marshall group of Michigan and its supposed 

 equivalent in other States, etc., by Alexander Winchell, Phil. Acad. Sci. Proc, vol. 17, 1865, pp. 109-133. 



4 Am. Jour. Sci., vol. 32, 1861, pp. 167-177, 288. 



6 The Marshall group: A Memoir on its geological position, characters, and equivalencies in the 

 United States. Proc. Am. Phil. Soc, vol. 11, 1869, pp. 57-83, and vol. 12, 1870, pp. 385-418. 



