JaNUAEY 17, 19U2.J 



SCIENCE. 



83 



species correspond in a remarkable degree 

 to those observed in western New York. 

 The encrinal limestone is the central mem- 

 ber in both localities, and the chief coral 

 zone lies just above this stratum in both. 

 A striking dissimilarity exists between the 

 Hamilton of Thedford and the correspond- 

 ing horizon (Traverse group) of Alpena, 

 Michigan, the next important outcrop of 

 this formation to the northwest. The dif- 

 ference is shown chiefly in the faunas. 

 The paper was discussed by J. M. Clarke, 

 H. S. Williams and A. W. Grabau. 



The Traverse Group of Micliigan: Amadeus 



W. Grabau, New York, N. Y. 



Two sections, one on Thunder Bay and 

 the other on Little Traverse Bay, show the 

 strongly calcareous facies of the strata, 

 which is most marked in the western sec- 

 tion. In both sections the upper limit of 

 the Traverse groups is marked by the St. 

 Clair Black shale, and the lowest portion 

 of the group is a bed of blue clay 80 feet 

 thick. The fauna varies with the rock. 

 The reef character of the limestone strata 

 was discussed. The faunal character of 

 the strata was discussed by Professor H. 

 S. Williams, and the reef structure by Mr. 

 Chas. D. Walcott. The Society then ad- 

 journed for lunch, many members availing 

 themselves of the opportunity offered to in- 

 spect Ward's Natural History establish- 

 ment, where a lunch was provided. 



The afternoon session was called to order 

 at 2 o'clock. The following papers were 

 read: 



The Lower Carioniferous Area in Indiana: 

 T. C. Hopkins, Syracuse, N. Y. 

 The Lower Carboniferous strata in west 

 central Indiana undergo quite marked 

 changes along the strike. The outcrops 

 have been traced in detail and represented 

 on the State map. The heavy calcareous 

 deposits of the southern part of the area 

 thin out to the northward and give way to 



argillaceous and sandy deposits. This 

 transition has an important bearing on 

 the geological history of this region. 



The following subdivisions, based on 

 lithologic but not paleontologic features, 

 were discussed. Kaskaskia, Mitchell, Bed- 

 ford; Harroddshurg and Enobstone. 



The paper was briefly discussed by W. 

 B. Scott, J. B. Wolf and W. M. Davis. Dr. 

 A. C. Lane discussed the relations of sim- 

 ilar beds in Michigan, and raised the ques- 

 tion as to the origin of the silica in the 

 beds under consideration, and its value as 

 a horizon marker. He suggested that it 

 might be supplied by volcanic eruptions, 

 even from a distance. Mr. Walcott briefly 

 discussed the economic importance of the 

 limestones of these formations. Brief re- 

 marks were also made by Dr. A. F. Foerste, 

 and responded to by Dr. Hopkins. 



Geological Horizon of the Eanaiuha Black 

 Flint: I. C. White, Morgantown, W. Va. 

 The first comprehensive description of 

 the Kanawha Black Flint was given by 

 W. B. Rogers, and besides this, the works 

 of Stevenson, the Piatt Brothers and H. 

 M. Chance were considered as having added 

 most to our knowledge of the details of the 

 Appalachian carboniferous stratigraphy. 

 The name Conemaugh, proposed by Frank- 

 lin Piatt, has, according to W. B. Clark, 

 priority over Elk River series applied to 

 the ' Barren measures ' of Rogers, by 

 White. Piatt's name was accepted for the 

 beds lying between the Pittsburg coal and 

 the Upper Freeport coal. The position of 

 the Kanawha Black Flint is at the base of 

 the Conemaugh series, though David White 

 places it some 200 feet down in the Alle- 

 ghany series from paleobotanie evidence. 

 The work of Messrs. Campbell and Men- 

 denhall was reviewed, the speaker disagree- 

 ing with their interpretations. The prob- 

 lem was attacked anew by the speaker and 

 from a new standpoint, by tracing the 



