338 



HYDROGRAPHY. 



the Columbia again turns to the southeast, and continues the same 

 course up to Smoke Island, a distance of 25 miles. Five miles above 

 the turn the prairie terminates, where a high basaltic bluff rises, 

 which I named Waldron's Bluff ; it is 3 miles in length, and rises 800 

 feet above the river. Above the turn at Oak Point there are two 

 islands, Gull and Weaquus; the former is 2 miles long, by one-third of a 

 mile wide, separated from the prairie land by the Kinak Passage, one- 

 eighth of a mile wide. Off its northwest end is a shoal, which must be 

 avoided. Weaquus Island lies to the north of Gull : it is quite small, 

 one-third of a mile long; it has a shoal surrounding it. The main chan- 

 nel passes to the north of Weaquus Island. When Plumondon Island, 

 which lies opposite to Waldron's Bluff, opens, steer for it. This course 

 will lead into the deepest water, and avoid the shoals which make 

 off the north shore, opposite to the upper end of Gull Island. Wala 

 Creek here empties into the Columbia. From it to the mouth of the 

 Cowlitz River there is an extensive prairie of several miles in 

 width, on which, near to the river bank, is situated Mount Coffin, a 

 regular cone, rising to the height of 720 feet. It is the only high 

 land on the north shore in this distance. 



Opposite to the upper part of Waldron's Bluff lies Walker's Island, 

 one-third of a mile from the shore : it is li miles long and one-sixth of 

 a mile wide. The best channel lies between it and the south shore, 

 but that on the north may be used, care being taken to avoid the shoal 

 making off from the east end of it. The shoal which lies above the 

 island has a small sandbank on it ; bare at low water. 



Latap Bluff lies on the south side of the river, and extends from 

 opposite Mount Coffin to Sandy Island, a distance of 11 miles; it is 

 450 feet high. The river from Waldron's Bluff to above the mouth 

 of the Cowlitz, I have named Mount Coffin Reach. Its average 

 width is nearly a mile. 



The mouth of the Cowlitz is 4 miles above Mount Coffin. At its 

 entrance into the Columbia it is one-sixth of a mile wide; off its mouth 

 lies Taney's Island, low and at times submerged ; it is one-third of a 

 mile long. The Cowlitz is serpentine, and cannot be navigated, except 

 when there is a freshet, or when its waters are backed up by those of 

 the Columbia ; then barges may ascend the Cowlitz a distance of 18 

 miles. 



Kanem Island lies 1 mile above the mouth of the Cowlitz, on the 

 northern shore, is 1 i miles long, and one-sixth of a mile wide. The 



