124 GEOLOGY. 



Marvine, a.. II. Position and General Geology of the Gold-Hill 

 Mining region. Amer. Journ. ser. 3, vol. viii. p^). 29-33 (with 

 sketch map). 



This paper is an Appendix to that of Prof. Silliman on Tellurium 

 ores of Colorado. The Gold-Hill Mining region is not far from the great 

 continental " divide," which has here a height of 13,000 feet. 

 This, formed of Archaean and metamorphic rocks, is covered on 

 the flanks by red beds, probably Triassic, which are followed by the 

 upturned edges of Jurassic and Cretaceous beds, with the Lignite 

 group (of disputed Cretaceous or Eocene age). The Archaean schists and 

 granites are pierced by many dykes of felsite-porphyry, with which the 

 Tellurium ores are connected. E. B. T. 



Meek, Prof. F. B. On the age of the Lignitic formation of the Bockj- 



Mountain Eegion. Amer. Journ. ser. 3, vol. viii. pp. 459-463. 

 This article is an abstract of the writer's discussion of this subject 

 in Hay den's Beport of the Geol. Survey of the Territories for 1872. 



MiLLEE, S. A. Position of the Cincinnati Group in the Geological 



Column of Eossiliferous Bocks of North America. Cincin. Quart. 



Journ. Sci. vol. i. pp. 97-115. 



Contains a review of the various subdivisions of the Silurian series, 



as developed in different portions of the North American area, with 



special references to the position of the " Cincinnati group." H. A. N. 



Newberry, Prof. J. S. Circles of Deposition in American Sedi- 

 mentary Bocks. Proc. Amer. Assoc, vol. xxii. B. pp. 185-196. 

 Dr. Newberry's views may be illustrated by the following arrange- 

 hient : — A. Betreating sea (mixed sediment) : Hudson, Helderberg 

 and Hamilton groups, Coal Measures. B. Open sea (organic) : Trenton, 

 Niagara and Corniferous groups, Carboniferous Limestone. C. Off shore 

 (mixed deposit) : Calciferous, Clinton, Schoharie and Waverly groups. 

 D. Shore (mechanical) : Potsdam, Medina, Oriskany, and Erie groups. 



G. A. L. 



. On circles of Deposition in Secondary Sedimentary Bocks, 



American and foreign. Proc. Lye. Nat. Hist. N. York, ser. 2, 

 no. 4, pp. 122-124 (abstract). 

 Application of the writer's ^iews (see before) to the succession of 

 Cretaceous beds between the Colorado Biver and the eastern part of 

 Kansas and Texas. Everywhere in that region the lowest member is 

 a sandstone or conglomerate; then comes a great limestone rich in 

 marine fossils, next a double series first of limestones and then of 

 clays, shales, and mixed sediments. In the discussion following the 

 paper Prof. Wtjrtz suggested for the three types of formations the names 

 Siliceous, Calcareous, and Aluminous. Prof. Newberry prefers the 

 terms Mechanical, Organic, and Mixed. G. A. L. 



. On the Linton Coal-bed and Fauna. Proc. Lye. Nat. Hist. 



N. York, ser. 2, no. 4, pp. 134, 135. 

 Remarks suggested by Prof. Cope's * Catalogue of Air-breathing Ver- 



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