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 lake. Only near the lake in little hollows along the shore can strawberries, lettuce, and other vegetables be grown,

An accurate survey of the shore lines of the lakes that spread their waters over the depression of the plateau country of the Central Andes would be a contribution to the study of the question of uplift in its effect upon man. The shore lines about many of the lake basins are still quite fresh and may be scen even from points many miles away as a thin white or light yellow line rounding the promontories and running up hollows and ravines, ‘There has been no major modification of the landscape since the basins were filled with water. Ac- curate mapping of the shore lines would tell us whether they stand level today as they must have done at the time of their development. If such mapping should show that broad re- gional tilting occurred, that the landscape has been deformed since the lakes have disappeared, it would throw at least a part of the period of deformation and uplift of the mountain belt into the period since the great Ice Age and increase the probability that the last of the great changes of climate and elevation in the Central Andes occurred during the period of human occupation.

We turn to some specific illustrations of the manner in which slight changes of climate may affect human occupation, whether such changes are brought about by uplift of the earth's crust or by other and more general causes affecting the whole world. Gunardo Lange, in the publications of the Museum of La Plata has described the ruins of a hill bordered by steep slopes, the long axis of the hill running from south to north, There is a principal fort on the broadest part of the summit and an advanced fort farther north on the highest point of the hill (Fig. 114). The material of the fortification consists of stone without mortar. The walls have an exterior height of