Geology. 499 



counties named. The salt industry of the state has also rapidly 

 declined in recent years, although at Maiden and other points it 

 has survived in consequence of the valuable by-products of 

 bromium and calcium chloride. A larger demand in the future 

 is expected. 



The treatment of the sandstones follows that of the limestones 

 described in Volume III. The Report contains much valuable 

 information as regards the different occurrences and the tests to 

 which the samples have been subjected. Here also it is noted 

 that a much greater extension of the industry in the state may 

 be looked for. 



3. Geological Survey of New Jersey ; Henry B. Kummel, 

 State Geologist. Annual Report for the year 1908. Pp. xi, 159, 

 with 21 plates, 6 figures. Trenton, 1909. — In addition to the 

 administrative report, the State Geologist contributes here some 

 further facts on the changes at Manasquan Inlet, and also 

 notes on the mineral industry of the state. The other two parts 

 of the volume are devoted to a general description of the zinc 

 deposits of Sussex County, by A. C. Spencer, and on the building 

 stones by J. Volney Lewis, the latter illustrated by excellent 

 colored plates. The report on the zinc deposits gives some of the 

 results developed by work done in cooperation with the U. S. 

 Geological Survey ; the facts are more fully presented in the 

 Franklin Furnace Folio noticed in vol. xxvii, p. 189. 



4. Relations betioeen local magnetic disturbances and the 

 genesis of Petroleum; by George F. Becker. U. S. Geol. Survey, 

 Bulletin 401. Washington, 1909. — The author has been led 

 from a consideration of the different theories for the origin of 

 the natural hydrocarbons, oil, gas, etc., to investigate the pos- 

 sible relations between the distribution of these hydrocarbons and 

 the variation of the compass needle. While some oils are doubt- 

 less of organic and others of inorganic origin, the fact that the 

 action of dry ammonium chloride on native iron results in a 

 copious evolution of hydrocarbons, suggests the derivation from 

 carbides of iron or other metals as an important source; it is well 

 known that such carbides exist both in artificial iron and in 

 various meteorites. By plotting the locations of petroleum 

 deposits in the country on a chart showing the isogonic lines for 

 1905, it is shown that the irregularities in the curves of equal 

 declination are strongly marked in the principal oil regions, and 

 the author regards these coincidences as too numerous to be 

 explained by accident. The relations thus brought out "are 

 compatible with the supposition that the great oil deposits are 

 generated from iron carbides, either by, or without, the agency 

 of water. Of these alternatives the latter is the more plausible. 

 What the map does prove is that petroleum is intimately associ- 

 ated with magnetic disturbances similar to those arising from the 

 neighborhood of minerals possessing sensible magnetic attraction, 

 i. e., iron, nickel, cobalt or magnetite. Henceforth no geological 

 theory of petroleum will be acceptable which does not explain 

 this association." 



