278 Revieivs — American Geological Surveys, Ohio. 



Survey, The old band of the Black slate proved to be Nos. 8 and 9 

 of the series. The Chemung group, which is a sand-rock in New 

 York, passes into a slate in Ohio. Not aware of this lithological 

 change, it is not strange that the earlier geologists attempted to cor- 

 relate it with the higher Waverley group. So satisfactory is the 

 new identification, that it was immediately adopted by the Geo- 

 logical Section of the American Association for the Advancement 

 of Science without a dissenting voice. The Huron shale is a new 

 name borrowed from the Michigan Survey, and it seems to be a 

 better designation than the New York equivalents. It had been 

 supposed to be the equivalent of the Hamilton. It contains the 

 Dinichthys Herzeri} The Erie shales on a superficial view appear to 

 be identical with the Huron group, but the imbedded fossils show that 

 the two groups do not run parallel to each other, — they meet along 

 the line of strike. They are 400 feet thick — and contain few 

 fossils of interest. 



The old Waverley series is now svib-divided in the north part of 

 the State into the Cuyahoga shale 150 feet, Berea grit 50 feet, 

 Bedford shale 60 feet, and the Cleveland shale 20 to 60 feet thick. 

 It is the equivalent of the Marshall group of Michigan, as earnestly 

 maintained by Winchell before the organization of the Ohio Survey. 

 Fifteen species of fish rewarded the collectors in 1869, belonging to 

 the genera Palceoniscus, Ctenacanthus, 'Gyracanthns, Orodus, Helodus, 

 Polyrhizodus, Cladodus. The Carboniferous Conglomerate is a hard 

 rock about 100 feet in thickness, forming the floor of the Coal- 

 measures, and containing many plants like those of the Coal-measures. 

 It is the Millstone -Grit of the Old World. 



None of the final results of the Survey will do more for the ad- 

 vancement of Palseontology than the history of the Coal-measures. 

 Dr. Newberry has devoted many years of his life to the study of its 

 plants and animals, and has finer illustrations of them than any other 

 person in the country. Fifty plates of drawings are ready for pub- 

 lication. There are ten workable beds of coal in this State, cover- 

 ing about one-fourth of its area, or 10,000 square miles, and belong- 

 ing to the ^reat Appalachian Coal-field. 



The material on hand a year since, ready for publication, was 

 sufficient to form an octavo volume of 500 pages, consisting of an 

 historical sketch of geological investigation in Ohio, descriptions of 

 physical geography, the relations of Ohio geologically to North 

 America, with detailed descriptions of the formations themselves and 

 their characteristic fossils. The first part of it has already appeared, 

 forming an octavo volume of 184 pages. 0. H. H. 



1 See Geological Magazine, 1868, Vol. V., p. 184. 



