. The Andes of southern Peru; geographical reconnaissance along the seventy-third meridian. Yale Peruvian Expedition (1911); Physical geography; Geology. PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 241 are marked by heavy beds of basal conglomerate and sandstone, and an abundance of ripple marking and other features associated with shallow-water and possibly near-shore conditions. CABBONIFEBOTJS Carboniferous strata are distributed along the seventy-third meridian and rival in extent the volcanic material that forms the western border of the Andes. They range in character from basal conglomerates,
. The Andes of southern Peru; geographical reconnaissance along the seventy-third meridian. Yale Peruvian Expedition (1911); Physical geography; Geology. PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 241 are marked by heavy beds of basal conglomerate and sandstone, and an abundance of ripple marking and other features associated with shallow-water and possibly near-shore conditions. CABBONIFEBOTJS Carboniferous strata are distributed along the seventy-third meridian and rival in extent the volcanic material that forms the western border of the Andes. They range in character from basal conglomerates, sandstones, and shales of limited develop- ment, to enormous beds of extremely resistant blue limestone, in general well supplied with fossils. On the eastern border of the FRONT RANGE. Fig. 159—Topographic and structural section at the northeastern border of the Peruvian Andes. The slates are probably Silurian, the fossiliferous limestones are known Carboniferous, and the sandstones are Tertiary grading up to Pleistocene. Andes they are abruptly terminated by a great fault, the continua- tion northward of the marginal fault recognized in eastern Bolivia by Minchin2 and farther north by the Coarse red sandstones with conglomeratic phase abut sharply and with moderate inclination against almost vertical sandstones and lime- stones of Carboniferous age. The break between the vertical lime- stones and the gently inclined sandstones is marked by a promi- nent scarp nearly four thousand feet high (Fig. 159), and the limestone itself forms a high ridge through which the Urubamba has cut a narrow gateway, the celebrated Pongo de Mainique. At Pasaje, on the western side of the Apurimac, the Carbonifer- ous again appears resting upon the old schists described on p. 236. It is steeply upturned, in places vertical, is highly conglomeratic, and in a belt a half-mile wide it forms true badlands topography. * Eastern Bolivia and the Gran Chaco, Proc. Royal Geogr. Soc, Vol. 3, 1881
Size: 3821px × 654px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbo, bookcentury1900, bookdecade1910, booksubjectgeology
