The Andes of southern Peru . andabove which are: 3. Lofty residual mountains composed of resistant, highly deformed rock, nowsculptured into a maze of serrate ridges and sharp commanding peaks. 4. Among the forms of high importance, yet causally unrelated to the otherclosely associated types, are the volcanic cones and plateaus of the western Cordil-lera. 186 THE ANDES OF SOUTHERN PERU 5. At tlie valley heads are a full complement of glacial features, such as cirques,hanging valleys, reversed slopes, terminal moraines, and valley trains. 6. Finally there is in all the valley bottoms a deep all
The Andes of southern Peru . andabove which are: 3. Lofty residual mountains composed of resistant, highly deformed rock, nowsculptured into a maze of serrate ridges and sharp commanding peaks. 4. Among the forms of high importance, yet causally unrelated to the otherclosely associated types, are the volcanic cones and plateaus of the western Cordil-lera. 186 THE ANDES OF SOUTHERN PERU 5. At tlie valley heads are a full complement of glacial features, such as cirques,hanging valleys, reversed slopes, terminal moraines, and valley trains. 6. Finally there is in all the valley bottoms a deep alluvial fill formed duringthe glacial period and now in process of dissection. Thougli there are in many places special features either re-motely related or quite unrelated to the principal enumeratedtypes, they belong to the class of minor forms to which relativelysmall attention will be paid, since they are in general of small ex-tent and of purely local interest. The block diagram represents all of these features, though of. Fig. 126—Block diagram of the typical physiographic features of the PeruvianAndes. necessity somewhat more closely associated than they occur innature. Reference to the photographs. Figs. 121-12-4, will make itclear that the diagram is somewhat ideal: on the other hand thephotographs together include all the features which the diagramdisplays. In descending from any of the higher passes to the val-ley floor one passes in succession down a steep, well-like cirque ata glaciated valley head, across a rocky terminal moraine, thendown a stair-like trail cut into the steep scarps which everywheremark the descent to the main valley floors, over one after anotherof the confluent alluvial fans that together constitute a large partof the valley fill, and finally down the steep sides of the inner val-ley to the boulder-strewn bed of the ungraded river. THE PERUVIAN LANDSCAPE 187 We shall now turn to eacli group of features for descriptionand explanation, selecting
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Keywords: ., bookcentury1900, bookdecade1910, bookidandeso, booksubjectgeology
