394 ScienUfic Intelligence. 



IJ. Geology and Mineralogy. 



1. United States Geological Suruey : C. D. Walcott, Direc- 

 tor. — The following publications have recently been received: 

 Folios No. 92. Gaines Folio, Pennsylvania-New York. 

 No. 93. Elkland-Tioga Folio, Pennsylvania; by Myron L. 

 Fuller and William C. Alden. 



These folios are specially interesting as an expression of the 

 revision of classification of the terminal Devonian formation of 

 the New York-Pennsylvania area based on recent surveys. The 

 classification adopted is as follows : 



f i Pottsville 30'-200' 



I Peimsylvanian •< Sharon conglomerate 60-100' 

 / Mauch Chunk O-lOO' 



Carboniferous <J 



[ Mississippian { ^^^^^^ 



1000' 



Devonian -{Cattaraugus 500' 



Chemung 600-2000' + . 



The definition of the formations is based upon lithologic charac- 

 ters. In describing the Chemung on the Gaines quadrangle the 

 author says : " It should be clearly distinguished from the paleon- 

 tologic division called Chemung which includes both the marine 

 fauna of the lithologic Chemung and the fresh and brackish 

 Avater i'auna of the overlying Cattaraugus and lower portion of 

 the Oswayo formations." In other words, the Chemung fauna 

 may be regarded as ranging above the Chemung formation and 

 as high as the lower part of the Oswayo formation. 



Lithologically the Chemung is limited below by the bluish 

 shales of the Portage, not reached in these quadrangles, and 

 above by the red shales of the Cattaraugus. Soft laminated 

 shales predominate ; limestones predominate in upper part ; 

 the thickest beds in the upper TOO or 200 feet. A single 

 bed of bright red shale is reported ? 300 feet down in the Tioga 

 quadrangle, and a thin lens of iron ore at same level, with 

 dull reddish brown shales still lower, A bed of gray cross-bed- 

 ded sandstone of Cattaraugus type is reported 60 or 100 feet 

 below the top. Vertical worm borings, concretions of sand, and a 

 few thin lenses of conglomerate are seen in the upper part of the 

 formation. Two horizons of iron ore beds are seen, one " close to 

 the top," the second 300 feet or more down. The upper is the 

 '' Mansfield " ore beds a few feet below the first red bed of the 

 Cattaraugus. Chemung character of rock and fossils are said to 

 occur for 50 to 100 feet after the reds of the Cattaraugus first 

 appear. 



The limits of the Cattaraugus are given as from the first pro- 

 nounced red beds upward for 500 feet, the upper limit arbitrarily 

 drawn. The red beds are thicker in the southeastern portion of the 

 area and are thinner and more widely separated by more pro- 



