August i8, 1910] 



NATURE 



217 



THE MINERAL SURVEY OF PERU. 

 'T'HE Cuerpo de Iiigenieros de Minas del Peru cont'nues 

 to issue actively its valuable bulletins on mining 

 areas. In No. 58 (lyoS) Mr. A. Jochamowitz reviews the 

 mineraj resources of the somewhat remote department of 

 Apurimac, in the mountains south-east of Lima, where the 

 rivers run northward along the ranges to join the great 

 flow of the .Amazon. The level lands are mainly devoted 



jtfl^f 



w from ill;; Lower Cretaceous Coal-beds of Cupisiiique, 1' 



to the cultivation of sugar-cane for the production of 

 alcohol ; but alluvial gold-areas exist, and gold occurs in 

 decomposed ferruginous zones among the prevalent stratified 

 quartzites. Portuguese miners in old days appear to have 

 secured most of the spoil that could be readily obtained. 



Mr. E. T. Duenas describes, in Boletin 62, the provinces 

 of Tayacaja, Angaries, and Huancavelica, famous for their 

 mineral wealth, from silver-lead to mercury and gold. 

 Here again alcohol is one of the main agricultural pro- 

 ducts, and the soil of the valleys, 

 when watered, is highly productive. 

 The sugar-cane crop, however, at pre- 

 sent suffers greatly from locusts. The 

 three provinces lie in a basin of the 

 Andes, between Lima and Cuzco, and 

 at the head-waters of the Mantaro. 

 The rocks are much faulted, with 

 crystalline masses thrust in among 

 them. A series of slates is regarded 

 as Silurian, and a red-rock series, con- 

 taining salt, and traceable into that of 

 Cuzco, is referred to the Trias. Meso- 

 zoic limestones and sandstones occur 

 in places, and fossils prove some of 

 these to be Liassic and others Upprr 

 Cretaceous (p. 154). The author (p. 

 24) explains the course of the Mantaro 

 as of double origin. The western 

 canon above Anco is ascribed to the 

 overflow of a lost lake in the upland 

 south of Jauja — this town, by the by, 

 might have been just squeezed into the 

 margin of the map. The second 

 canon past Coris and Surcubamba was 

 cut by the waters of another lake, the 

 " Lago de Huanta," which has left 

 its gravels below .Anco and as far 

 south as .Acobamba. The Jauja lake drained into this near 

 .■\nco. Both cafions are connected with faults running out 

 from the .Andes, and their excavation in Quaternary times 

 was thus facilitated, until they grew large enough to drain 

 off their respective lakes and unite in the sinuous course 

 that now forms the Mantaro. We wish that the resources 

 available in the United States Survey for the topographical 

 representation of such problems had been at the disposal 

 of Mr. Duenas in Peru. Wolfram occurs at Lircay, in 



NO. 2129, VOL. 84] 



the province of Angardes, and the author reviews the 

 world's production of tungsten, now so important an 

 element (p. 118). Mesozoic coal-seams are found in 

 Huancavelica. It would have been convenient for refer- 

 ence if the name of this province had not appeared at the 

 top of all the pages of the memoir. 



The great rise in the price of antimony in 1907 leads 

 Mr. E. Weckwarth (No. 68) to review tlie occurrences of 

 antimony ores throughout Peru, including antimonial lead 

 and silver ores. The bulletin also 

 forms a compact monograph on the 

 uses of antimony and its metallurgical 

 extraction. No. 69 (iqog), by Mr. E. 

 du Bois Lukis, lias geographical and 

 geological interest, in addition to its 

 description of a mining area. It 

 describes the coal-bearing strata of the 

 country near Cajamarca, in the midst 

 of the Andes, and contains numerous 

 photographs of the somewhat barren 

 scenery of the highland. Even at 

 Cupisnique, only 40 km. from the coast, 

 we are up among rocky walls and desert 

 features that remind one of the Witte- 

 bergen of South Africa (Fig. 1). Stein- 

 man n has referred the coal-bearing 

 sandstones at this point to the Lower 

 Cretaceous. In the extensive Pifiipata 

 held away to the north-east, above the 

 long Maranon valley, the coal is prob- 

 ably of much the same age (p. 31). 

 These Peruvian coals, which crop out 

 on the hillsides, among strata that 

 can be traced for miles across a rocky 

 country, are mostly anthracitic, with a 

 rather high percentage of ash ; but a 

 considerable future is predicted for them, and the Depart- 

 ment of Mining Engineers, as in other bulletins, sounds 

 a patriotic note, and urges the Peruvians themselves to 

 do something towards the development of their re- 

 sources. 



The coast of southern Peru, and the Pampas west of 

 the -Andes, are studied by Mr. V. F. Marsters in Boletin 

 70 (1909). Here again the numerous illustrations appeal 

 to the geographer, and include several features due to 



Fig. 2.- 



ed alluvial valley-flo 



* Afequipa, with the 



recent volcanic outbreaks. The huge cone of Misti 

 (Fig. 2), more than 22,000 feet in height, appears in 

 several views. A small picture even shows the snow-flecked 

 rim of the crater, with its broad central cone. The pampas 

 are swelling plains of detrital material, which is often of 

 volcanic origin, and volcanic cones sometimes break their 

 surface. They rarely show features due to erosion, and in 

 places contain traces of saline pools. The discovery of a 

 limited deposit of caliche, or nitrate-bearing earth (p. 6ii, 



