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 situations already described. In each case the topographic out- lines are as clear an index of their manner of formation as are the shells found upon the terraces at Paita, Camana, and Cal- dera. Though these embedded and contemporary shells are interesting confirmatory evidence, they are not really essential to the proof of formation by the sea and geologically recent up- lift, for the topographic evidence is of a thoroughly conclusive sort.

lf the boldness of the desert coast is a measure of Andean scenery the traveler may well fecl that what lies ‘behind the ranges”’ is worth crossing the desert to sec. It is therefore no less than astounding to climb the steep and in places precipi- tous coastal scarp (Fig. 44) and find oneself among tame and rounded hills that form the summit and castern border of the Coast Range (Fig. 94, p. 267). 1t is only the coastal scarp that is physiographically young; the Coast Range has every mark of great antiquity. It is not a bold mountain range but the wreck of one. It is one of the “‘old lands’ of South America. After erosion had reduced it to its present smoothly molded aspect there came a time of profound crustal disturbance. The floor of the Pacific broke away from the edge of the continent and sank to abyssal depths. At the same time the land rose. Yet so recently in geological time have these great events taken place that the old erosion surfaces formed when the land was thousands of feet lower may still be seen not merely on the summit of the Coast Range but in the high cordillera itself. It is by such differences of form and scenery that the physiog- rapher is able to continue the calendar of the years where the record of geological deposits is altogether missing.

The older rocks and forms show that the sea was once over what is now land and that the whole shape and contour of the continent were wholly different from what they are today. Great masses of granite were then intruded into the coastal belt, bowing it up to form a range which was subsequently eroded to its very roots. Were we able to see a picture of the coast of that time it would show a shore line probably not un- like that of the Guianas today. That the old forms of the Coast Range are still visible and but little modified from their orig-