williams.] HALL, ORTON, HERRICK. 187 



James Hall, 1 in a paper before the American Association, discussed 

 the limitations between the Cheniuug and Waverly groups, according 

 to paleontological evidence. Spirifera disjuncta is considered as char- 

 acteristic of the upper part of the Chemung. Concerning the sand- 

 stones and conglomerates which had been considered as of Carboniferous 

 age, it has been found by a study of the fossils that they represent the 

 upper member of the Chemung group. Above them occurs a series of 

 non-fossiliferous shales of unknown thickness. The correlation of this 

 series of rocks was studied by Mr. C. E. Beecher, who prepared a section 

 exhibiting about 1,500 feet and a list of fossils characteristic respectively 

 of the Chemung group and of the Waverly group following it. 



From the record of a well in Cleveland, Ohio, Edward Orton 2 deter- 

 mined the thickness of the shales below the Berea grit. 



This well was commenced about 760 feet above tide-water and about 

 75 feet below the Berea grit. The first rock met was Bedford shale, 

 followed by the Devonian shales, classified by Dr. Newberry as the 

 Cleveland, Erie, and Huron divisions, and having a thickness of 1,3C0 

 feet. 



In the years 1885 to 1888 C. L. Herrick 3 applied to the solution of the 

 Waverly problem the new methods of correlation previously elaborated 

 by Williams in the interpretation of the upper Devonian formations. 

 (See chapter on the Chemung-Catskill problem.) 



This paper is a fine illustration of what can be done in the way of 

 dissecting out the individual faunas, showing their composition, and 

 determining their affinities with faunas of other regions by a minute 

 study of local geology. 



Although the study was primarily of a local series of faunas, the 

 author has made abundant use of material from other regions for com- 

 parison. The result is that we have a valuable series of the successive 

 faunas of the Lower Carboniferous formations of central Ohio, which 

 will serve as standards in all future work in correlation. 



The great mass of the paper is devoted to specific descriptions ; the 

 final results of the study are given in volume iv. 4 



The section is divided into three parts or divisions by two conglom- 

 erates ; these are subdivided into ten zones, and at the close a list of 321 

 species is given with the particular position or range in this scale of 

 each species. 



1 Hall, James : Note on the intimate relations of the Chemung group and Waverly sandstone in 

 northwestern Pennsylvania and southwestern New York. Am. Assoc., Proc, vol. 33, 1884, pp. 416- 

 419. 



2 Orton, Edward: The record of the deep well of the Cleveland Rolling Mill Company, Cleveland, 

 Ohio. Am. Assoc. Proc, vol. 34, 1885, pp. 220-222. 



3 Herrick, C L. : A sketch of the geological history of Licking County, accompanying an illustrated 

 catalogue of carboniferous fossils from Flint Ridge, Ohio. Denison Univ., Bull., vol. 2, pp. 5-68, 144- 

 148; vol. 3, pp. 13-110; vol. 4, pp. 11-60, 97-123, 1885-1888, with numerous plates illustrating the fossils. 



* Ibid., pp. 95-114. 



