May 19, 1921 abstracts: geology 237 



ment along such deep faults, but admits that the folds in the region considered 

 have characters which could not be accounted for in this way. The "granite 

 ridge" which is overlain directly by Pennsylvanian rocks must have originated 

 in late Mississippian or early Pennsylvanian time, perhaps by movement 

 along one of these deep-lying faults. Successive movements along these 

 lines at distinct periods have resulted in different effects at different depths. 

 The origin of the assumed deep-lying faults is ascribed to pre-Cambrian moun- 

 tain-building movements, as all subsequent movements in this Mid-Continent 

 region are considered inadequate to have produced them. M. I. Goldman. 



GEOLOGY. — The Lance Creek oil and gas field, Niobrara County, Wyoming. 

 E. T. Hancock. U. S. Geol. Survey Bull. 716-E. Pp. 32 (91-122), pis. 4. 

 1920. 



The Lance Creek field lies in east-central Wyoming, west of the Hartville 

 uplift which connects the Rocky Mountains and the Black Hills. It is 

 probably separated from that uplift by a broad syncline. Cretaceous and 

 Tertiary formations from about 1660 feet below the top of the Cretaceous 

 Pierre shale up to the Tertiary White River formation and Quaternary'' al- 

 luvium are exposed. The sinuous anticline from which oil and gas are being 

 obtained, as represented on a map by 100-foot contours, has a dominant 

 east- west trend but turns north at its east end and south at its west end. 

 The total length of the a:xis is probably about 20 miles, the closure of the 

 anticline about 1,000 feet. The north and west flank is steep with dips up 

 to 27° but on the south flank the dips run from 2^/2° to 5°. 



Production is being obtained from what the author considers the Newcastle 

 sandsto-ne about 200 feet above the Dakota sandstone, around 3,500 to 4,000 

 feet below the surface. The yield of the principal wells ranges from 250 to 

 2,500 barrels of oil and from 8 million to 30 million cubic feet of gas per day. 

 The author suggests testing deeper beds at least to include the Jurassic Sun- 

 dance formation which he estimates could be reached, by a well located on the 

 top of the anticline, at a depth of about 4,200 feet. He also draws attention 

 to the possibility of production from the Wall Creek sandstone which lies 

 about 1,050 feet above the Newcastle sand. M. I. Goldman. 



ENTOMOLOGY. — The colonizing reproductive adults of termites. T. E. 

 Snyder. Proc. Ent. Soc. Wash. 22: 110-150. 1920. 



This paper, which was presented to the Faculty of the Graduate School of 

 George Washington University as part of the requirements for the degree of 

 Doctor of Philosophy, summarizes the literature and the author's extensive 

 field notes of the colonizing habits of the reproductive adults of white ants. 

 The three types of reproductive forms are discussed in detail, the nymphs 

 characterized, and methods of colonization described. The results of the 

 breeding experiments and attempts at cross-breeding are set forth. A sum- 

 mary of the paper and conclusions drawn is given and the article concluded 

 by a list of the literature cited. S. A. Rohwer. 



ENTOMOLOGY. The subfamilies of Formicidae, and other taxonomic notes. 

 WiLLLVM Morton Wheeler. Psyche 27: 47-55. Figs. 3. 1920. 



This short paper gives a phylogenetic tree of the various subfamilies of ants. 

 It also includes descriptions of new genera and subgenera and some remarks 

 on the digestive system. S. A. Rohwer. 



