724 REVIEWS 



covering most of the eastern portion of the peninsula indicates that 

 beneath (i) the layer of relatively free circulating soft surface waters 

 there is (2) an important horizon of sodium chloride waters, beneath 

 which (3) the water is nearly saturated, in many places, with calcium 

 chloride. It is suggested that the lowest waters are connate, indicating 

 therefore the composition of sea water at the time of deposition of the 

 rocks. The presence of copper chlorides in the lower water, the mode of 

 occurrence of the copper deposits, the chemical character of the altera- 

 tions of the rock, and the low temperature gradient of the region are all 

 thought to be consistent with the theory that the copper has been 

 deposited in zones of relatively low oxidation by the waters. The ulti- 

 mate source of the copper must be the formation itself, which as a whole 

 carries about o . 02 per cent copper. R C M 



Le Revermont, etude sur une region karstique du Jura meridional. 



By Georges Chabot. Ann. d. Geog., XXII (1913), pp. 339- 



415. Maps 2. 

 The Revermont is a fragment of the southern Jura Mountains more 

 or less separated from the main part of the range by the valley of the 

 river Ain. While physiographically and structurally an integral part 

 of the Juras, by reason of its position bordering the fertile plains of 

 La Bresse, it is geographically a dependent of the latter. Coralline and 

 foraminiferal limestone of Sequanien to Kimeridgien (Jurassic) age 

 forms the floor of the Revermont valleys, most of which are in the syn- 

 clines of the highly folded strata. Local conditions make the work of 

 ground-water very important. Large inclosed depressions or sinks into 

 which surface waters drain are characteristic, and comparatively recently 

 the Suran River has dried up completely in the lower part of its course, 

 the water disappearing beneath the surface. The soil is poor and 

 cultivation difficult. Consequently for a number of years there has been 

 a depopulation of the district. R C M 



A New Gypsum Deposit in Iowa. By G. F. Kay, U.S. Geol. Surv., 

 Bull. 580, pp. 59-64, Fig. 11. 

 The discovery of a deposit of gypsum in the Mississippian rocks of 

 the central southern portion of Iowa is of scientific interest. The 

 gypsum, with some anhydrite, occurs at a depth of more than 500 feet. 

 Whether it will prove to be of economic importance is undetermined. 



R. C. M. 



