Barrett and Merriam, however, give data only for the southernmost part of the Kato range, including an area of approximately 150 square miles. The remainder of the Kato territory extended some distance along the upper waters of the South Fork of the Eel River and its area may be reckoned as 100 square miles or 40 per cent of the entire Kato territory. On the other hand, living conditions were not as good in this portion of the range and the density was probably less than in the vicinity of Laytonville and Branscomb. Hence we may add 300 persons (rather than the full 40 per cent) and consider the total as 1,100. With the Kato we arrive at an area where it becomes possible to utilize historical and documentary, as well as ethnographic, sources of information. For the period 1850-1856 there are three accounts left us by white men who were direct observers, as distinguished from data supplied from memory to modern white men by Indian informants. With respect to the region north of San Francisco Bay these observations by Americans must be regarded as supplementary to the basic ethnographic material derived from Indians. Nevertheless they are of considerable value in confirming, negating, or modifying the ethnographic data. Two primary sources are pertinent here. The first is the expedition of Colonel Redick M'Kee, one of the three "commissioners" sent out in 1851 to negotiate treaties with the California Indians. M'Kee went first to Clear Lake, then up the Russian River, over to the Eel River watershed, down to Humboldt Bay, and eventually up the Klamath and Trinity rivers. Two records of this expedition were kept. The first, and far better known, is the Journal of George Gibbs, which was later published by Henry R. Schoolcraft (1860). The other is the Minutes of the expedition, written by John M'Kee, a relative of the Colonel. These Minutes, together with considerable correspondence, were published in Senate Executive Document No. 4, 33rd Congress, Special Session (1853). The second source is a report written by Major H. P. Heintzelman at the request of Indian Agent Henley, in 1855. Major Heintzelman (1855) made a survey of the tribes of Sonoma and Mendocino counties which might be placed upon a reservation at the mouth of the Noyo River. He interviewed numerous headmen, or chiefs, of community units and reported on the Indian population. His total, for the territory extending from the upper Eel River to San Francisco Bay was 21,200, a figure in excess of the value conceded by ethnographers.