It must also be constantly borne in mind that the Spanish records themselves do not give us an absolutely undistorted picture of aboriginal conditions. It is very evident from the reports of the earliest official pioneers, like Garcés in 1776 and Martin in 1804, that from 1770 onward and perhaps even before white men had straggled into the valley and had consorted with the natives. There is reason to believe that these unknown interlopers may have introduced diseases which adversely affected the population and may have initiated a process of general social disruption. The best we can do is get as close to the prehistoric condition as the records allow. Two other demographic consequences arise from this very early white contact. In the first place, the documentary record, if we ignore Garcés for the moment, runs nearly continuously from 1804 to approximately 1840. During this long period an uninterrupted change was going on among the native population: the population was _continually decreasing_. Hence later reports tend to deviate from earlier ones, and indeed may show an entirely new state of affairs arising within a very few years. In the second place, the deterioration in certain areas took place so rapidly in the first part of the nineteenth century that any information secured from informants alive since 1900 is completely useless. Unless very good documentary evidence is available for such areas, there is no recourse but to fall back on the method of extrapolation and area comparisons. The principal Spanish accounts upon which we must rely include a few which have been published. Most of them, however, are to be found in manuscript form in the Bancroft Library, University of California, Berkeley. Some of them were translated for an unpublished manuscript by the Late Professor Herbert I. Priestley and several were translated for Dr. C. H. Merriam. Merriam's translations are on file in his manuscript collection. The citations to these accounts, published and unpublished, are given in the manuscript section of the Bibliography. In this text they are referred to, without further citation, by the author's name and date. THE TULARE LAKE BASIN