Itinerary 13 



valley. The uniformity of the walls is also broken at intervals by 

 deep gashes cut by tributary streams through the basalt sheet. 

 Above the upstream limit of the basalt sheet low mountains rise a 

 short distance back from the valley walls near the boundary line. 

 From here to the upper limit of the Ramparts the green slopes 

 which replace the basalt walls are frequently broken by shattered 

 pinnacles, bold crags, and minarets of brilliantly tinted rocks. 



About ten miles above the lower entrance to the Upper Ram- 

 parts, opposite the mouth of Salmon-Trout River on a small bench 

 of Pleistocene fluvial sediments that rise about forty feet above the 

 river level, the Hudson Bay Company formerly maintained a trading 

 post called Rampart House. Later this settlement was moved up 

 the Porcupine about thirty miles to remove all doubts about its 

 position in regard to the boundary line. This establishment was 

 designated New Rampart House and the former site was known as 

 Old Rampart House. New Rampart House is situated a short dis- 

 tance east of the 41st meridian of longitude that separates Canada 

 from Alaska and about two hundred and ten miles by river from Fort 

 Yukon at the mouth of the Porcupine, on an elevated bench of 

 Pleistocene silts similar to that where the older post was located. 

 These are the only two areas of such deposits of any extent through- 

 out the Upper Ramparts. The Hudson Bay Company have dis- 

 continued trading posts on the Porcupine River for the past eight 

 or ten years and for this reason apparently it has been abandoned by 

 Indians, who now frequent it only upon occasional hunting excur- 

 sions. 



Above the Upper Ramparts which terminate about twenty-five 

 miles east of the international boundary the river meanders out into 

 another basin filled with Pleistocene silts. This area appears to be 

 much more extensive than the Coleen Basin and the designation 

 Bluefish Basin is suggested for it because it appears to be drained 

 largely by that river. The Porcupine flows along its northwest 

 margin, the channel frequently abutting directly against the old 

 limestone formation of the Upper Ramparts, the higher extension 

 of which along the north side of the valley forms the Old Crow 

 Mountains, the summits of which attain elevations of about two 

 thousand feet along the river. The river presents the same features 

 as already described for its course through the Yukon Flats and the 

 Coleen Basin except that greater thicknesses of silts are exposed. 

 Here they rise to heights of one to two hundred feet above the 

 river and present almost vertical exposures on the concave sides of 

 the banks. On some of these high blufifs elevated ice-beds were 



