

williams.I EATON, BRONGNIART, NUTTALL. 25 



II. Transition class 



7. Argillite. 



8. Metalliferous limestone. 



9. Graywacke. 

 10. Red Sandstone (including those of " Catskill 



Mountains, Oswego River, Niagara River, and 

 Connecticut River"). 



{11. Breccia. 

 12. Compact limestone. 

 13. Gypsum (Manlius, Onondaga, Madison, etc.). 

 14. Secondary sandstone. 



IV. Superincumbent class .... { £ »»!„, trap . 

 V. Alluvial class { J* gggj^ 



This follows the general system of Bakewell, who was a disciple of 

 Werner; but the individual strata are partly peculiar to his own sys- 

 tem, although distributed in the several classes of the Wernerian classi- 

 fication. 



In 1821 we find a notice of the occurrence of "blind coal" on the 

 bank of the Arkansas, 500 miles from its mouth, "equal to the best 

 Kilkenny coal f this by L. Bringier. 



In a letter to Silliman (the editor of the American Journal), dated 

 1820, Brongniart writes about fossils in a way to show how they were 

 then used, and to what a slight extent they were of value in the inter- 

 pretation of geologic strata. He says 1 in regard to Trilobites : " I 

 learned from these specimens, and from some others which I received 

 in different ways, that Trilobites existed in America as well as in Europe ; 

 that the animals differed very little (if, indeed, they constantly differed 

 at all) from those of Europe, and that they are, in both cases, found in 

 the Schists phy Hades, or in the transition limestone, or, at least, in those 

 which are very ancient." 



Ebenezer Granger noticed some vegetable impressions from the coal 

 formation of Zanesville, Ohio, and recognized them as Lepidodendra and 

 Calamites, but did not further identify them. 



Thomas Nuttall 2 , of Philadelphia, records some " Observations on 

 the Geological Structure of the Valley of the Mississippi." He gives 

 an account of the probable limits and character of the "secondary 

 formations" in the Mississippi Valley. He compares the calcareous 

 platform of the Mississippi (as seen in the plains of Ohio, Michigan, 

 Indiana, Illinois, Kentucky, western Tennessee, and Missouri) to the 

 plains of the Tartarian district, traversed by the Kuban, as described 

 by Pallas and Clarke, and he states that he thinks he meets in these 

 calcareous deposits " almost every fossil described and figured in Mar- 

 tin's Petrifacta Derbiensia." 



Although he makes no allusion to specific identification, this is a 

 clear recognition of the " Carboniferous rocks " in these limestones of 

 the interior. 



In 1822 Zachariah Cist gave an account of the Lehigh and Schuyl- 



1 Am. Jour. Sci.. vol. 3, p. 226. 



8 Jour, of the Acad, of Sci. of Philadelphia, 1821, vol. 2, pp. 14-65. 



