18i;0.] ^^ [Winohcll. 



agreeing "in general cliaracter and ])osition''^ with "the Black Shale 

 stratum of Ohio and Indiana." '^ 



In 1841, when Professor Hall was closing up his labors upon the geology 

 of Western New York, he undertook an extended tour through the west- 

 ern states for tlie purpose of ascertaining to what extent the formations 

 recognized in New York could be traced in other regions. The general 

 residts of this tour were announced in 1842.16 At this time, he was led 

 to regard the Waverly series (einbraciiig everything between the Black 

 Shale and the Conglomerate), as a prolongation of the Chemung and Por- 

 tage groups of New York. The thick bedded sandstones at Newburg and 

 Waverly were identified with the Portage sandstones, while the shaly 

 sandstones and flags near Cleveland were regarded as representing the 

 Gardeau shales and flagstones. From Newburg to Cuyahoga Falls, and 

 also at Akron, he identified the shales and sandstones of the Chemung 

 group. 



Passing down the Ohio into Indiana, Prof. Hall again identified strata 

 corresponding to the Portage, and doubtfully to the Chemung ; while 

 above these, and beneath the carboniferous limestone, was a series of are- 

 naceous strata becoming interstratified above with beds of mountain lime- 

 stone, and, on the whole, exhibiting affinities Avith the Carboniferous 

 system. Nevertheless he inclined to regard them as " sub-carboniferous' ' 

 (used in the sense of suhter-carhoniferous,) remarking that " a limit should 

 be fixed between what is to be strictly referred to the Carboniferous period, 

 and older deposits." "■ The Black Shale of Ohio and Indiana was regarded 

 by Professor Hall as the equivalent of the Marcellus Shale of New York 

 "being the only representation of that rock, the Hamilton group and the 

 Genesee slate" (lb. 280). 



During the same year, Mr. Conrad '^ read a paper before the Aca4emy 

 of Natural Sciences of Philadelphia, in which he embraced brief descrip- 

 tions of three fossils from the IVIarshall sandstone of Moscow, Michigan, 

 which he referred to the Carboniferous system. Mr. Yanuxem's Report 

 on the Geology of the Third District of New York, also appeared this 

 year. 



In 1847 the distinguished European geologist, de Yerneuil, gave the 

 world the results of an extended and critical investigation of the parallel- 



ij It is interesting to note tliis early identification of the now styled Marshall sandstones with 

 the cliaracteristic portion of the Waverly sandstone series; and the Black Shale of Michigan with 

 the Black Shale of Ohio and Indiana ; as these opinions were expressed by Hubbard anterior to 

 the first elaborate attempts by Hall and de Verneuil to trace the parallelism of formation in the 

 different states. Dr. Houghton had, indeed, previously recognized the correspondence of the "Black 

 Shale " with certain formations in western New York, as described in the annual reports of that 

 State ; though there is room to doubt whether he made the identification preferably with the ?Iar- 

 cellus or the Genesee Shale. Under the great natural difficuities attending the exploration of the 

 ''wilderness of Michigan," then just emerging from a territorial condition, and the equally great 

 embarrassments resulting from the undisturbed condition of the strata, it is indeed remarkable 

 that the early geologists of the state succeeded in establishing so many conclusions which have 

 stood the test of nearly a third of a century. ,- 



16 Amer. Jour. Sci. and Arts, xhi p. 51 ; Jour. Bost. Soc. Nat. Hist. v. p. 1, and more fully in 

 Trans. Assoc. Amer. Geol.,p. 267. See also Geol. Eep., Fourth Dist. N. Y., p. 229. 



1' Trans. Assoc. Am. Geol., p. 281. '« Jour. Acad. N. S., Phil., vol. viii, p. 249 and 2ii9. 



