STRIKE FIORDS 



Archipelago is so direct in its course that a straight line 

 190 miles in length could be laid out upon it without 

 touching either shore. It heads in the mainland at the 

 extreme north and, trending a little east of south, termi- 

 nates in the Pacific coast. The southern three-fifths, which 

 bears the name Chatham Strait, has an average width of 

 about seven miles; the northern two-fifths, known as 

 Lynn Canal, averages five miles. Our direct observation 

 was restricted to the northern part. 



This straightest of all the passages is also deepest. No 

 soundings have yet been charted for the southern third, 

 but those of the northern part indicate that a continuous 

 channel can be traced with 700 feet as its minimum 

 depth, and the maximum depth, as already mentioned, is 

 2,900 feet. The bounding mountains, so far as we saw 

 them, are 4,000 to 5,000 feet high, and the full depth of 

 the trough is in the neighborhood of 6,000 feet. At its 

 head the trough divides into four parts, which penetrate 

 the upland, first as fiords or inlets and then as river val- 

 leys. These parts diverge from their point of junction 

 like the ribs of a fan, their directions ranging from north 

 to northwest; and their courses are remarkably straight, 

 especially in the lower parts. 



The unusual straightness of this great trough naturally 

 suggests that its course was determined by some struc- 

 tural feature, such as a fault or the outcrop of an easily 

 eroded rock. Its breadth is in better accord with the 

 second of these tentative explanations; but the matter is 

 not free from doubt. If the trough is a strike valley, we 

 should naturally expect to find parallel valleys associated 

 with it, but the number of such is limited. A short 

 parallel trough lies fifteen miles west of Lynn Canal 

 and contains Excursion Inlet. East of Chatham Strait 

 are Seymour Canal and Stevens Passage, which are 

 approximately parallel. But a number of other features 



