472 Reviews — The United States Geological Survey. 



rocks that the iron-ores have been formed. Five types of deposit are 

 recognized: (1) beds and irreguhar masses of hematite representing 

 nearly complete replacements of dolomite ; (2) layers of hematite in 

 crystalline dolomite; (3) small replacement deposits in sediments 

 at the contact of minor quartz-monzonite intrusions ; (4) veins in 

 quartzite ; and (5) veins in quartz-monzonite. The first type 

 includes quite 80 per cent of the ore in the district. The ore is 

 now in the form of hematite, but the occurrence of pseudomorphs 

 shows that magnetite and pyrites were the original minerals formed 

 by the replacement. A consideration of the ore-bodies and of the 

 associated rocks shows that they result from the replacement of 

 dolomite by ore-bearing solutions of deep-seated origin : the replace- 

 ment followed the intrusion of the quartz-monzonite sills, but it 

 preceded certain minor intrusions of aplite, quartz-diorite, and soda- 

 syenite-porphyry. 



No fossils having been found, nothing is known of the precise age 

 of the quartzites or of the periods at which the intrusions took place. 



3, Bulletin No. 530 (1913) consists of " Contributions to 

 Economic Geology (Short Papers and Preliminary Reports). 

 Part I. — Metals and Non-metals except Fuels". Part II, on 

 " Mineral Fuels", was noticed in the Geological Magazine for July 

 (p. 322). In the work before us there are reports on gold, silver, 

 copper, lead, zinc, iron, manganese, aluminium ores, and on some 

 rare metals such as vanadium, carnotite, etc. There are notes and 

 bibliographies on clays, fuller's earth, building stone, gypsum, glass- 

 sand, asphalt, abrasive materials, phosphates, mineral paints, sulphur, 

 graphite, etc. 



Bulletin No. 537 (1913) is on "The Classification of the Public 

 Lands ", by Mr. George Otis Smith and others. It contains accounts 

 of the laws relating to agricultural, mineral, coal, and other lands; 

 and of the methods of classification of lands and their valuation 

 in reference to various minerals, water-power and reservoir sites, 

 public water reserves, etc. It should furnish useful information and 

 suggestions to the many owners and land-surveyors now concerned in 

 this country in the valuation of estates. 



4, Water-supply Paper No. 259 (1912), by Messrs. M. L. Fuller 

 and F. G. Clapp, deals with "The Underground Waters of South- 

 western Ohio", containing a general description of the topography 

 and geology, and special accounts of the geology and water prospects of 

 each county. The chemical character of the waters is discussed by 

 Mr. 11. B. Dole, who considers the suitability of various waters for 

 domestic, industrial, and medicinal purposes, likewise the physical 

 qualities of waters, the suspended mineral matter, the growths of 

 microscopic plants, and the questions of purification and softening. 

 No. 293 (1912) is on the "Underground Water Resources of Iowa", 

 a voluminous report separately printed also by the Iowa Geological 

 Survey (see Geol. Mag. 1913^ p. 226). No. 297 (1913) consists of 

 part iii of a "Gazetter of Surface Waters of California", by Mr. B. D. 

 Wood, dealing with the Pacific coast and Great Basin streams. No. 300 

 (1913), by Messrs. H. D. McGlashan and H. J. Dean, is on the "Water 



