The total for San Francisco and San José equals 1,848 baptisms. Adding an estimated 400 for Santa Clara makes 2,248. This figure, which has to be regarded as a minimum for population since it covers only mission baptisms from the region, is as great as the estimates based on the expeditions of the first decade of settlement, and proves beyond question that those estimates were highly conservative. If we assume that the aboriginal population was twice the value of the baptisms, the total would have reached 4,496. If it be allowed that conversion close to the missions was exceptionally rapid and thorough, a somewhat lower figure may be accepted, say 3,000. This estimate, however, must be regarded as the lowest consistent with the known facts. Although little direct information pertaining to population can be secured, it is nevertheless interesting to consider the prehistoric sites in the East Bay which have been noted by California archaeologists. Most of those which can be regarded as habitation mounds have been recorded by the University of California Archaeological Survey, and have been plotted on map 1. Area 1 Area 2 Area 3 Area 4 Area 5 Total San Francisco 33 206 211 297 15 762 Santa Clara 400 San José 347 136 603 1,086 --- --- --- --- --- ----- Total 380 342 211 297 618 2,248 It must not be thought that each site represented on the map by a dot was inhabited in 1769, or the years immediately preceding, for many of the mounds are known to have been formed during the Middle Culture period, which antedated modern times by several centuries. The chief physical characteristic of these accumulations is the very high content of mussel, and to some extent clam, shell. From this feature it has been deduced that at one time a very large population existed along the shore of the Bay. The record of known sites, as shown on map 1, is valuable, not as an indication of the size of population, but rather of its distribution. Admitting that perhaps the majority of the sites along the Bay shore from San Leandro to Crockett were abandoned before 1770, it is still apparent that the areas designated on the map as Alamedan and Huchiun contained a heavy concentration of inhabited spots. This conclusion is in conformity with the waterfront habitat and the probable large food reserves. Along the strait and the southern shore of Suisun Bay the known habitation mounds are less numerous, but there are enough to indicate a reasonably high population density. This area on the map has been ascribed to Karquin.