Geology and Natural History. 427 



1 8. The Ore Deposits of New Mexico ; by Waldemar Lind- 

 GREN, Louis C. Graton and Charles II. Gordon. U. S. Geol. 

 Sill-., Professional Paper No. 68, 1910. Pp. 349, 33 figs., 22 pis. — 

 The mining districts of New Mexico form a belt extending from 

 the north central part of the state to the southwest corner. 

 Silver or gold, or both, are present in nearly all of the districts 

 and as a rule are accompanied by copper, lead and zinc. A 

 great number of types of ore deposits are represented in New 

 Mexico. Among them are copper and ii'on ores in sedimentary 

 beds ; fissure veins ; mineralized shear zones ; lenticular bodies ; 

 replacement deposits ; contact metamorphic deposits ; placers. 



The pre-Cambrian schists contain disseminated ore in shear 

 zones and veins of copper and zinc sulphides with some gold but 

 little silver; the Paleozoic limestones carry irregular copper, lead 

 and zinc deposits ; the intrusive porphyries and granites contain 

 fissure veins with gold and silver ; finally, the rhyolite and ande- 

 site inclose fissure veins rich in gold and silver. The major part 

 ot the deposits occur in or near the many, usually small, areas of 

 intrusive rocks — mostly monzonites— which extend across the 

 state. 



The study of the ore deposits of the state has resulted in the 

 establishment of various periods for their formation with distinct 

 characteristics for each period. Thus the pre-Cambrian deposits 

 are mainly lenticular veins, shear zones and " fahlbands " in 

 schists which carry chiefly gold and copper. In late Cretaceous 

 or early Tertiary time widespread intrusion took place along 

 what is now the mining belt. After these intrusions most of the 

 metal deposits were formed ; they consist of contact-metamorphic 

 deposits, veins, shear zones and silver-lead replacements in lime- 

 stone. In the latter part of the Tertiary period lava flows 

 occurred in certain sections and at several places fissure systems 

 in these rocks were filled with gold and silver ores. The age of 

 the copper deposits in sandstone has not been fully established. 

 Their formation probably commenced after the general uplift in 

 the early Tertiarj^, when atmospheric waters began to penetrate 

 the Red Beds, from which the deposits are believed to have con- 

 centrated their copper ores. w. e. f. 



19. Meteor Crater in Northern Central Arizona ; by D. M. 

 Barringer. Pp. 24, with 21 plates and maps (privately printed). 

 — The Meteor Crater in Arizona, or Coon Butte as it was earliei 

 called, is unquestionably one of the most remarkable spots on the 

 earth and the problems that it presents have never been faced 

 elsewhere. It has been described by numerous writers since 

 attention was first called to it by A. E. Foote in 1891.* A very 

 full and satisfactory accountf of the locality and the associated 

 meteoric material with a discussion of the origin of the crater was 

 given by G. P. Merrill two years since in volume 1 of the Quarterly 

 Issue of the Smithsonian Miscellaneous Contributions for January, 



*See this Journal (8), xlii, 413, 1891. 

 t Ibid (4), XXV, 265, 1908. 



