March 13, 1908] 



SCIENCE 



409 



The Nomenclature and Subdivisions of the 

 Upper Siluric Strata of Michigan, Ohio 

 and Western New Torlc: A. C. Lane, 

 Charles S. Prosser, W. H. Sherzer 

 and A. W. Grabau. 



The Monroe formation of Michigan and 

 Ohio comprises a number of paleontologie 

 zones, each ranging through from fifty to 

 two hundred feet of strata. The species 

 of each zone are restricted to it, and the 

 zones are recognizable at widely distant 

 localities. The lowest of these extends into 

 western New York, having been named by 

 Grabau, in 1898, the "Greenfield forma- 

 tion," and being represented in eastern 

 New York by the Cobleskill Limestone. 

 The characteristics of the several divisions 

 were discussed, and the conclusions 

 reached by the four authors given. Names 

 for the divisions were proposed and their 

 distribution given. 



The papers were discussed by A. C. Law- 

 son, A. P. Coleman, A. M. Miller, H. M. 

 Ami, I. C. White and A. C. Lane. 



The concluding paper of the afternoon 

 was 



Structure and Stratigraphy of the Ouachita 

 Ordovician Area, Arkansas: A. H. Pur- 

 due, Fayetteville, Ark. 

 Discussed by A. C. Lane and G. K. Gil- 

 bert. 



Soon after 5 o'clock the society ad- 

 journed and at 7 :30 met again in the 

 dining room of the Hotel Alvarado for its 

 annual dinner, which was enjoyed by 

 thirty-seven persons, including a few of 

 the prominent educators of the territory. 



SESSION OF TUESDAY, DECEMBER 31, 1907 



The society convened at 9:10 a.m., with 

 President Van Hise in the chair. The re- 

 port of a committee favoring the establish- 

 ment of a series of stations for the study 

 of volcanic and seismic phenomena was 

 adopted. The consideration of an over- 



ture on the formation of a Committee on 

 Geological Nomenclature was deferred to 

 the end of the session. The report of the 

 council was accepted and ordered printed 

 in the Proceedings, and the auditing com- 

 mittee was continued and given leave to 

 report to council. The society then pro- 

 ceeded with the reading of papers, the first 

 two being presented together by Professor 

 J. E. Wolff. They were 



Notes on the Crazy Mountains, Montana: 

 John E. Wolff, Cambridge, Mass. 

 The Crazy Mountains were visited by 

 the author in 1883 and 1889, and a paper 

 on their geology was published in the Pro- 

 ceedings in 1892. Last summer, with Dr. 

 G. E. Mansfield and Mr. H. B. Merwin, a 

 review was made of their physiographic 

 and geologic features, and some three hun- 

 dred photographs were obtained, dealing 

 with points of especial interest. One small 

 glacier was discovered and visited, and an- 

 other, not so readily accessible, was noted; 

 the relative age of the granite-diorite stocks 

 and of alkali-syenite was found and minor 

 points determined. After a review of the 

 geology of the mountains and of their spe- 

 cial features, the results of last summer's 

 work were described and the whole illus- 

 trated by a small selection of lantern slides. 

 The accompanying paper, by Dr. Mans- 

 field, was included in Professor Wolff's 

 presentation. 



Glaciation in the Crazy Mountains of Mon- 

 tana: George Rogers Mansfield, Cam- 

 bridge, Mass. (Introduced by J. E. 

 Wolff.) 



During the Glacial Period the Crazy 

 Mountains were the seat of local glaciation. 

 All the higher valleys contained small gla- 

 ciers, as indicated by the numerous cirques. 

 Some of the glaciers on the south and east 

 slopes attained considerable size, notably 

 those of Big Timber and Sweetgrass-Amer- 

 ican Fork canyons, which must have had 



