The remaining portion of the Yokuts-Miwok territory lay in the valley and foothills north of the Merced River. This area (see maps 1 and 5, areas 8-13 inclusive), particularly the delta of the San Joaquin and Sacramento rivers, was entered relatively early by the Spaniards and by the year 1820 had been almost completely swept of its native population. The names of many whole tribes have been lost and the exact locations of many others are now almost impossible to ascertain. Of village names only those few are known to us which were preserved, often by chance, in the mission records and accounts of expeditions. Several attempts have been made to reconstruct the aboriginal human geography but none has been entirely successful. Kroeber's account, which accompanies his discussion of the Plains Miwok and northern Yokuts in the Handbook of California Indians, is manifestly incomplete. Merriam's paper on the Mewan Stock of California (1907) is helpful, but probably the best work of the modern investigators is that of Schenck (1926). The early nineteenth-century accounts for this region are also less satisfactory than for the central and southern parts of the San Joaquin Valley. Moraga's record is useful only for the Tuolumne River, and the delta is covered only by Abella and Duran. It is true that both Sutter and Gatten give figures for villages south of Sacramento but their information pertains only to the badly depleted natives of the 'forties. Hence their censuses are of little value for assessing the aboriginal condition.