Mat 8, 1908] 



SCIENCE 



723 



distributed in layers that generally strike 

 and dip with the surrounding rocks. 



The sedimentary rocks are correlated 

 with the Grenville series of Bast Ontario 

 and the Adirondacks. 



Petroleum Fields of Illinois in 1907: H. 

 Foster Bain, director of the Illinois 

 Geological Survey, Urbana, 111. 

 The author declared that in 1907 Illinois 

 will produce more than 24,000,000 barrels 

 of crude petroleum. This is more than 

 any state in the union, save California, 

 produced in 1906 and in fact more than 

 any country, save Russia and the United 

 States. Production began here in June, 

 1905, with 5,489 barrels. The oil is of 

 good grade, running about 32° Baume. It 

 ocsurs in Carboniferous strata in Clark, 

 Cumberland, Crawford and Lawrence 

 counties. A number of different pro- 

 ducing horizons have been recognized rang- 

 ing from Upper Coal Measures down to 

 the Chester group of the Mississippian. 

 There is marked irregularity in pressure, 

 in productivity and in relations to gas and 

 salt water in the different pools, and it 

 seems likely that final studies will lead to 

 important conclusions regarding the genesis 

 and accumulation of the oil. 



General Petrology of Wisconsin Igneous 

 Bocks: S. Weidman, Madison, Wis. 

 This paper described the general chem- 

 ical features of a large area of intrusive 

 igneous rocks in central and northern Wis- 

 consin. These were intruded as three sepa- 

 rate or distinct magmas, as rhyolite, dio- 

 rite-gabbro and granite-syenite. Phases of 

 the granite-syenite magma are the highly 

 interesting and rare rocks, nepheline-syen- 

 ites and associated pegmatites. The sev- 

 eral intrusive magmas are each character- 

 ized by relatively high alumina and low 

 magnesia. The nepheline-syenites and as- 

 sociated quartz-syenites are especially char- 



acterized by high alumina and low mag- 

 nesia and in them are developed such rare 

 minerals as fayalite and hedenbergite as 

 important rock constituents. Several un- 

 usual rock phases are developed. All the 

 igneous rocks of the region show a close 

 chemical relationship, and this close rela- 

 tionship is especially well illustrated in the 

 chemical character of the minerals devel- 

 oped in the syenites and pegmatites. 

 Geology and Mining Industry of Chihua- 

 hua, Mexico: Rurus M. Bagg, Jr., 

 Urbana, 111. 



The author described briefly the main 

 topographic features of the state of Chi- 

 huahua and explained their bearing upon 

 the mineralization of the region. 



The geologic formations were also dis- 

 cussed and the main types of ore deposits 

 classified. Many examples of mines were 

 cited to illustrate these types. The history 

 of mine development and the future out- 

 look of the mining industry in Chihuahua 

 were discussed in conclusion. 



Niagaran and Oriskanian in the Western 

 Part of Virginia: E. B. Branson, Ober- 

 lin, Ohio. (Read by title.) 



The Earthquake of 1872 in the Owens Val- 

 ley, Calif ormia: Willard D. Johnson, 

 D. C, and W. H. Hobbs, Ann Arbor, 

 Mich. (Read by W. H. Hobbs.) 

 This paper consisted principally of the 

 description of a series of photographs and 

 specially detailed maps of the country af- 

 fected by the Owens Valley earthquake. 

 The maps exhibited in an unusually fine 

 manner the courses of recent faults in the 

 valley and their general characteristics. 



A Design for a Universal Seismograph 

 with Duplex Recorders for Horizontal 

 Motion: C. P. Marvin, U. S. Weather 

 Bureau, Washington, D. C. 

 The author described the construction of 



a single seismograph that will give every 



