abstracts: geology 19 



GEOLOGY. — -The transportation of debris by running water. Grove 

 Karl Gilbert. Based on experiments made with the assist- 

 ance of Edw. Chas. Murphy. U. S. Geological Survey Profes- 

 sional Paper 86. Pp. 263. 1914. 

 For original brief statement of results see this Journal, 4: 154-158. 



1914. 



GEOLOGY. — The Montana group of Northwestern Montana. Eugene 

 Stebinger. U. S. Geological Survey Professional Paper 90-G. 

 Pp. 68. 1914. 

 For original brief statement of results see this Journal, 4: 383-384. 

 1914. 



GEOLOGY. — A reconnaissance in the Canyon Range, west-central Utah. 

 G. F. Loughlin. U. S. Geological Survey Professional Paper 

 90-F. Pp. 10. 1914. 



The formations studied are all of sedimentary origin and include 

 limestone of lower Mississippian (Madison) age, quartzite of probable 

 upper Mississippian age, Eocene conglomerates and sandstones, and 

 the Pleistocene Lake Bonneville beds. The principal structural fea- 

 tures are a series of folds, some open and others close, one of the latter 

 being accompanied by a strike fault of probable reverse character. 

 Evidence of "basin range" faulting is also present. The contact 

 between Eocene and Carboniferous strata indicates that the former 

 were deposited on an erosion surface of considerable irregularity. 



The folding of the Carboniferous rocks is believed to have taken 

 place in late Jurassic or post-Jurassic time. This was followed by an 

 erosion period, in Cretaceous time, and by deposition of the Eocene 

 strata, which probably once covered the entire area of the present 

 range. The volcanic eruptions took place in late Eocene or post- 

 Eocene time. The volcanic period was followed by profound faulting 

 and uplift of the range. Sevier River maintained its course during the 

 uplift, cutting through the Eocene beds and following a probable pre- 

 Eocene synclinal valley in the quartzite. Pleistocene time was marked 

 by the deposition of the Lake Bonneville beds and subsequent erosion 

 of them along the present course of Sevier River. 



The ore deposits of the range, which is included in the Leamington 

 mining district, include small replacement bodies of oxidized and sul- 

 phide lead-zinc ore, with low silver values, and also small showings of 

 oxidized copper minerals in quartz veins, which have been only super- 



