308 Bibliographical Notices. 



forest. It is followed by one-seed juniper and pliion. The other 

 coniferous trees form individually but small percentages of the total 

 growth, and are confined to more or less circumscribed tracts. 

 Among the broad-leafed species, aspen takes first rank, but is closely 

 followed by the oaks. The rest of the species of this class consists 

 of isolated trees or small groups scattered on the breaks to the 

 larger canyons." 



And at page 18 of the same no. 7 Forestry memoir : — " The 

 aborescent growth in the Reserve falls naturally into three chief 

 types or divisions, with one which is intermediate or transitional. 

 These types in their altitudinal extensions, and in the species which 

 correspond in a general way to the different ratios of precipitation 

 which prevail over the various districts in which they are found. 

 Yet here, as elsewhere, the soil-moisture, not always closely propor- 

 tioned to the annual precipitation, comes into play, and limits the 

 range of the different types, or extends it into areas where other- 

 wise they would not occur." 



At pages 30 and 31 of " no. 8 " both the natural retention and the 

 " run-off" of rain-water in a forested area are carefully considered, 

 with true scientific application of the topographical evidences. 



The Geology and Ore-deposits of the Bisbee Quadrangle, Arizona. 

 By Fkederick Leslie Raxso-Ue. 168 pages. 4to. With 29 

 plates and 5 text-figs. Government Printing Office, Washington, 

 1904. 

 This memoir is the " 21st Professional Paper" of the United States 

 Geological Survey, and, as usual with that series, contains a 

 trustworthy and complete description of a definite region as to 

 its production of materials useful for arts and manufactures, and 

 its surface-features, geological structure, and its palaeontology, all 

 carefully observed, noted, and illustrated by members of the 

 Survey, under the superintendence of the Director, C. D. Walcott. 

 The Volume before us treats of an ■ important copper district in 

 Arizona, the territory lying south of Utah, near the mouth of 

 the great Colorado River, and forming part of one of the 

 great metalliferous regions of N.W. America. The strata of the 

 country belong to the Precambrian, Cambrian, Devonian, Carbon- 

 iferous, and Cretaceous formations, and there are superficial beds 

 of Quaternary age. Some of the older strata have been more 

 or less metamorphosed by contact with the intrusive granite and 

 granite- por2)hyry of post-Carboniferous date. There are also dykes 

 of later date and less importance, probably doleritic, but much 

 altered. 



This work, by Mr. F. L. Ransorae and his colleagues, is richly 

 illustrated with good geological maps, views, and sections, and with 

 characteristic fossils, also plans and details of mining. The distribu- 

 tion, the genesis, and condition of the ores, both of primary and 

 secondary origin, are considered, the latter having been enriched by 

 the natural leaching of copper-salts from the pyrites lying at a 

 higher level. The limonite and kaolin, met with in local abundance, 



