The Mattole-Sinkyone boundary begins at Spanish Flat on the coast and goes northeast from there, crossing the Mattole River just above the mouth of Upper North Fork, Mattole River, and continuing in that direction to the headwaters of the Bear River. I have altered Merriam's map on this point. It shows the Mattole-Sinkyone line reaching the coast at Big Flat, a point about six miles down the coast from Spanish Flat. Merriam's notes say, however, that the line ends at Spanish Flat. Merriam's line crosses the Mattole River near the town of Upper Mattole about five miles below the mouth of Upper North Fork, but Goddard's Mattole informant gave him villages as far up as the mouth of Upper North Fork and I have considered this fact to be decisive. Nomland's Mattole-Sinkyone line reaches the coast at Four Mile Creek, about five miles up the coast from Merriam's line at Spanish Flat. This line of Nomland's is probably a tribelet boundary, which Merriam and Goddard give as occurring at about that point (see Mattole Tribelets). Otherwise Nomland's boundary agrees with that of Merriam. Merriam's line dividing the northern or Lolangkok Sinkyone from the southern or Shelter Cove Sinkyone begins in the east on South Fork Eel about a mile or two above the mouth of Salmon Creek, runs west from there through Kings Peak, and crosses the Mattole River just north of Ettersberg, intersecting the Mattole line a few miles from the coast. This line as given is the same as Merriam's, except that his begins in the east at Redwood Creek instead of at Salmon Creek. The change here is based on Goddard's village list, which indicates the present line. The Lassik-Nongatl line begins in the east just below Ruth on the Mad River. It goes west from there around the headwaters of the Van Duzen River until it crosses the Eel at the mouth of Dobbyn Creek and thence west to the Sinkyone line. Kroeber and Merriam agree on the eastern part of this line but Essene disagrees with them, including a much larger portion of the drainage of the Mad and Van Duzen rivers in Lassik territory. I am at a loss to explain this version, since Essene's informant from the Lassik was the same one consulted by Merriam. It is not clear that Essene's boundaries were obtained from his informants, and this fact may explain the discrepancy. I have accepted the Kroeber-Merriam line here. To the west of this, Kroeber's line, instead of crossing the Eel, follows the river toward the northwest, so none of the main Eel River valley falls in Nongatl territory. Goddard gives villages on the main Eel which are said to be allied with others in the Blocksburg region, so the Nongatl must have claimed at least a small section of the Eel. I have therefore accepted the Merriam version.