Geology and Mineralogy. 237 



SCIENTIFIC INTELLIGENCE. 



I. Geology and Mineralogy. 



1. United States Geological Survey. — The following publica- 

 tions have recently been received : 



Professional Papers No. 21. — Geology and Ore Deposits of 

 the Bisbee Quadrangle, Arizona ; by E. L. Ransome, 162 pp., 

 29 pis., 5 figs. — The lowest rocks of the Bisbee district are pre- 

 Cambrian schists derived from arkose sediments and separated 

 from the overlying Paleozoic beds by a profound unconformity. 

 Cambrian quartzite, 4500 feet of limestone belonging to Cambrian, 

 Devonian, and Carboniferous time, and 4500 feet of Cretaceous 

 sediments constitute the strata represented. Faulting and fold- 

 ing accompanied by intrusions of granitic magmas and by min- 

 eralization occurred at the close of the Carboniferous. Later 

 disturbance took place in post-Cretaceous time. The effect of 

 intrusion of granite porphyry is inconspicuous. Faults in this 

 region are numerous and the larger ones are located along a 

 NW.-SE. tract about 2-j- miles wide. Certain of the reversed 

 faults are occupied by dikes intruded during the faulting. None 

 of the workable ore deposits occur as lodes or fissure veins. 

 With few exceptions the deposits, from which 400,000,000 pounds 

 of copper have been taken, are irregular replacements of lime- 

 stone. 



No. 22. — Forest Conditions in the San Francisco Mountain 

 Reserve, Arizona; by J. B. Leiberg, L. F. Rixon and A. Dod- 

 well, with an introduction by F. G. Plummer, 91 pp., 7 pis. 



No. 23 — Forest Conditions in the Black Mesa Forest Reserve, 

 Arizona ; by E. G. Plummer from notes by L. F. Rixon and A. 

 Dodwell, 60 pp., 7 pis. 



No. 28. — Superior Analyses of Igneous Rocks from Roth's 

 Tabellen 1869 to 1884, arranged according to the quantitative 

 system of classification; by H. S. Washington, 51 pp. The 

 chemical analyses of rocks published from 1884 to 1900 inclu- 

 sive, are collected in Professional Paper No. 14. To this have 

 now been added the more reliable and complete earlier analyses. 

 The poor quality of early analytical work is made evident from 

 Doctor Washington's selections. Analyses made previous to 

 1861 are discarded; of those made between 1861 and 1884 

 10*24 per cent are retained; and of those made between 1884 

 and 1900 64*70 per cent are worthy of permanent record. Of 

 5,303 analyses made between 1861 and 1900 inclusive, 2,112 or 

 39*83 per cent are classed as superior. 



Bulletins. No. 224. — A Gazetteer of Texas; by Henry Gan- 

 nett, 176 pp., 8 pis. As revised in the second edition the Gazet- 

 teer of Texas is a model for such work. Besides the list of place 

 names, data are given regarding soil, climate, education, industries 

 and other geographic elements. 



