The Andes of southern Peru . *C :j « ?*i u m C ^ 07 O a o u< Fh on s o rt o **-t 1^3 *c: a CJ o ti; -^ -a o 2 = O o 0) F-. o c c cs Q) o OS 5 CJ ^ ;3 rt IV 2 q :S ? p H CO r~! A CH ^ c_ C3 « § 3 -te 5 o (h OJ C -*-3 c) X Qj n ?^ ^ G O PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 24-7 tlie region now occupied by the Andes. However, from the rela-tion of the Carboniferous to the basal schists, and the most con-servative extension of the known Carboniferous, it may be in-ferred that the Carboniferous sea did not completely cover theentire area but was broken here and there by island masses in t
The Andes of southern Peru . *C :j « ?*i u m C ^ 07 O a o u< Fh on s o rt o **-t 1^3 *c: a CJ o ti; -^ -a o 2 = O o 0) F-. o c c cs Q) o OS 5 CJ ^ ;3 rt IV 2 q :S ? p H CO r~! A CH ^ c_ C3 « § 3 -te 5 o (h OJ C -*-3 c) X Qj n ?^ ^ G O PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 24-7 tlie region now occupied by the Andes. However, from the rela-tion of the Carboniferous to the basal schists, and the most con-servative extension of the known Carboniferous, it may be in-ferred that the Carboniferous sea did not completely cover theentire area but was broken here and there by island masses in theform of an elongated archipelago. The presence of land plantsin the Carboniferous of Pisco warrants the conclusion that a sec-ond island mass, possibly an island chain parallel to the tirst, ex-tended along and west of the present EvS Alluvium ^^limestonelHIDSandstone 5 Shale ^Volcanic CEETACEOtJS The Cretaceous formations are of very limited extent in thebelt of country under consideration, in spite of their generallywide distribution in Peru. Theyare exposed distinctly only onthe western border of the Cor-dillera and in special the gorge of Cotahuasi, overseven thousand feet deep, abouttwo thousand feet of Cretaceouslimestones are exposed. Theseries includes only a very re-sistant blue limestone and ter-minates abruptly along a well-marked and highly irregnilarerosion surface covered by al-most a mile of volcanic ma-terial, chiefly lava flows. Thecharacter of the bottom of thesection is likemse unknown,since it lies apparently far be-low the present level of ero-sion. The Cretaceous limestones of the Cotahuasi Canyon are every-where greatly and irregularly disturbed. Typical conditions arerepresented in the maps and sections. Figs. 166 and 167. They are
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Keywords: ., bookcentury1900, bookdecade1910, bookidandeso, booksubjectgeology
