Linear distances along streams are useful as a basis for comparison in country where the rivers are similar ecologically but are clearly separated spatially and where the human population is concentrated along the stream banks to the exclusion of the interfluvial hinterland. Where a territory is marked by a network of creeks and sloughs, and the intermediate land is marsh, the linear comparisons become impossible. Areas must be substituted.
In relation to the present problem three such areas may be delineated. The first comprises the territory of the Bolbones (including all the subordinate villages) and the Leuchas. Following Schenck's map, it embraces all the land between the channels of the San Joaquin plus a strip approximately two miles wide east of the main river in T1 and 2S, R6E which accounts for the Leuchas. The area, as projected from a large-scale map onto coördinate paper, is 775 square miles, the population 3,400, and the density 4.39 persons per square mile. The second comprises the home of the Ochejamnes, Guaypem, Quenemsias, and Chucumnes-Chuppumne. For the habitat of these groups we have followed Schenck as far as possible. Our line runs actually from the junction of the east and west channels of the Sacramento at the foot of Grand Island southeast to the main channel of the San Joaquin, thence northeast and north to just east of Walnut Grove and then, at a distance of about 2 miles east of the eastern channel of the Sacramento, to a point 4 miles north of Courtland. Here the line crosses the river and continues downstream, 2 miles west of the river, to the starting point. This strip of the western bank of the western branch of the Sacramento is included in order to take in the Chucumes, who may have lived on the west side of the river. The area of this territory is 330 square miles, the population 2,950, and the density 8.94 persons per square mile.
The third area is the one shown by Schenck as belonging to the Chupunes, Tarquines, Julpunes, and Ompines, with the exception of the region east of the San Joaquin attributed to the Tarquines. For reasons stated previously the author does not believe that the Tarquines occupied this spot aboriginally. A strip 2 miles wide is included on the north shore, however, between Rio Vista and Collinsville, in the probable land of the Ompines. The eastern boundary is formed by the borders of areas one and two. In area three there are 600 square miles. The mean of the densities of the other two areas is 6.67 persons per square mile. Hence the population would have been 4,002 persons. No significance should be attributed to the third and probably also the second digit in these numbers. They are used only for purposes of estimate.
The three methods employed have yielded respectively 3,000, 2,000, and 4,000 as the most likely population of the five groups here being discussed. In default of any other evidence we may take the average 3,000.
(Chupunes, Tarquines, Ompines, Julpunes ... 3,000)
Adding the totals for the tribes known to inhabit the delta region of the great rivers and the southern shore of Suisun Bay, we arrive at a total population of 9,350.
Delta area ... 9,350
It is now preferable to depart from a strictly tribal sequence and revert once more to a classification based upon river basins. Three areas of this type are sufficiently clearly marked out; those corresponding to (1) the Cosumnes River, (2) the Mokelumne River, and (3) the lower San Joaquin River from just below the Merced to the head of tide water near Manteca. The inhabitants may be designated village or tribal groups in accordance with the river system where they were located.
The Cosumnes group.—On the river of this name lived the large and important aggregate of peoples known popularly as the Cosumnes, which included a restricted tribelet or subgroup also called Cosumnes. Ethnically a portion of the Plains Miwok, they extended from Sloughhouse close to the foothills, along the lower course of the Cosumnes River to its confluence with the Mokelumne near Thornton, and from that point northwestward to the Sacramento. The tribe as a whole was divided into either villages or tribelets, the names of many of which have come down to us from the Spanish records or have been ascertained by informants from ethnographers. As might be expected, there is considerable confusion among the different sets of names.
The mission documents are replete with village and tribal names but the number of baptisms was not as large as might be anticipated from what must have been a very populous aggregate of natives. The reason probably lies in the fact that missionizing expeditions to the Cosumnes were preceded by exploratory and punitive expeditions which, to be sure, brought home a few converts but which were chiefly preoccupied with military objectives. The Cosumnes, together with the Mokelumnes and other peoples of the lower San Joaquin Valley, had the time and the opportunity to develop great facility in the raiding and stealing of livestock and consequently for many years were in a state of uninterrupted war with the coastal settlers. The bitter hostility thus generated, together with the aggressive psychology which accompanied successful physical opposition to the Spaniards, made extensive conversion to Christianity very difficult. As a result the relative proportion of the natives baptized was unquestionably much lower than among the bay and delta tribes previously considered. The baptisms which appear in the mission records follow.