218 



SCIENCE. 



[N. S. Vol. XVII. No. 423. 



Geological Society for reading before that 

 body as a part of its program, with the 

 exception of five which were read before 

 Section B Monday afternoon (there being 

 no vice-presidential address this year), and 

 the papers dealing with the Lesser Antilles 

 and the recent eruptions there, which were 

 read before the same body Friday morn- 

 ing, the Geological Society adjourning at 

 that time for the purpose of attending the 

 meeting of Section B. 



The Shifting of Faunas as a Problem of 

 Stratigraphic Geology: Henry S. Wil- 

 liams, Yale University. 

 A comparison of sections through the 

 Upper and Middle Devonian rocks of the 

 New York-Pennsylvania province discloses 

 marked differences in the faunas which 

 occur at corresponding levels. The ex- 

 planation of the facts is found in the shift- 

 ing of faunas during the time represented. 

 The paper discussed at length the nature, 

 extent and mode of recognition of faunal 

 shifting in studying stratigraphy, and 

 modifications were suggested in the cus- 

 tomary practice of correlating formations 

 by their fossils. 



Some Relations of Tertiary Formatiotis of 

 the Northern Great Plains: N. H. Dar- 

 TON, U. S. Geological Survey. 

 For several field seasons, the author has 

 given a portion of his attention to the 

 formations from Oligoeene to Pliocene in 

 age of Nebraska, South Dakota and eastern 

 Wyoming and Colorado. Structural and 

 stratigraphic relation^ have been deter- 

 mined, and the origin and geologic history 

 of the formations have been considered. 

 In studying the Black Hills, Big Horn 

 Mountains and Laramie range, it has been 

 found that there are extensive overlaps of 

 the White River Oligoeene beds to high 

 altitudes where there are old shore lines 

 which define some of the physiographic 

 conditions. The materials of the forma- 



tions have been deposited principally by 

 streams, but at some points fine-grained 

 materials have been laid down in wide- 

 spread overflows or in local lakes and 

 bayous. 



The Economic Geology of Michigan: Al- 

 fred C. Lane, Lansing, Mich. 

 The author defines economic geology as 

 the science of raw materials. The effect 

 of the presence of these materials upon 

 industry and the effect of geological con- 

 ditions upon their development were il- 

 lustrated by reference to several Michigan 

 products. Such factors were considered 

 as the position of the state in the center 

 of the Great Lake distributing system, the 

 tilting of the Great Lake basin and its 

 effects, the mutual relations of coal and 

 iron and the development of the iron-ore 

 business, the peculiai-ities of lake copper 

 as compared with that of the far west. 

 Salt, limestone and lumber and their mu- 

 tual relations, the coal basin and the causes 

 of its retarded development, were consid- 

 ered. 



Some BesuUs of the Lake Minnesota Geo- 

 logical Survey: N. H. Winchell, Min- 

 neapolis, Minn. 



This paper mentioned: (1) Some of the 

 scientific conclusions, and (2) some of the 

 known economic results of the Survey pre- 

 sented in the final report. (1) Scientific: 

 (a) The identification of the parts of the 

 Upper Cambrian, (&) the definition of the 

 Lower Silurian, (c) the determination of 

 the extent of the Cretaceous toward the 

 east, (d) the definite determination of the 

 duality of the ice epochs, (e) the deter- 

 mination of the duality and alternation of 

 the ice lobes and the restiltant glacial 

 lakes, (/) the discovery of the duality and 

 later of the triple character of the iron 

 horizons of the Lake Superior region, (g) 

 the separation of the Archaean into two 

 non-conformable parts, (7i) the discovery 



