172 



KNOWLEDGE. 



June, 1915. 



southwards, part of the west side of Kniglit Island, 

 and most of the coast from Knight Island tt) within 

 four or ti\e miles of I'ort l.atouchc. Along the 

 soutli-west roast of the main branch of Kussell 

 Fiord the uplift varies from two feet downwards. 

 On the coasts of Nunatak Fiord the level on both 

 sides seems unchanged, (ii) The areas of depression 

 are much smaller. Here and there along the coast 

 from Yakiitat to Knight Island and in the neigh- 

 bouring islands, in a short length of the coast to 

 the north of Knight Island, and at the southern 

 end of the south branch of Kussell Fiord, the land 

 has been lowered by amounts ranging up to seven 

 or eight feet, (iii) The areas of elevation arc much 

 larger and the amounts of elevation are in some 

 cases extraordinary. The coast from four or five 

 miles south of Fort Latouche to near the entrance 

 to Russell Fiord has been uplifted by amounts 

 ranging from seven and a half feet to nearly eighteen 

 feet, and on Haenke Island by more than nineteen 

 feet. The most remarkable uplift of all is that of 

 the west coast of Disenchantment Bay between 

 Turner and Black Glaciers. Here the rise ranges 

 from thirty-seven feet to the greatest ever recorded 

 in any earthquake — of forty-seven feet four 

 inches. The north-cast shore of the main branch 

 of I^ussell Fiord has undergone a nearly uniform 

 elevation of about seven feet, while both shores of 

 the southern branch, except the south coast, have 

 been raised by amoimts varying from three to ten. 



A remarkable feature in the changes of elevation 

 is their rapid variation in amount over a short 

 distance of the coast. For instance, at one point 

 on the west coast of Disenchantment Bay the 

 amount of the uplift is forty-two feet, about a mile 

 to the west it is thirt}- feet, and about a quarter of a 

 mile farther it is nine feet. On the cast side of the 

 same bay the uplift is seventeen feet one inch close 

 to the north end of the peninsula ; in the small 

 island (Osier Island) just to the north of the 

 peninsula there is no evidence of any change of 

 level. In the main portion of Russell Fiord, which 

 is about a mile and a half wide, the elevation is 

 slightly more than seven feet along the east coast, 

 and less than two feet along the opposite shore. 

 At the southern end of the south branch of Russell 

 Fiord the change of elevation varies suddenly 

 from an uplift of se\"cn feet four inches to a 

 depression of five feet. 



Nature of the Deformation. — Such sudden 

 variations in the changes of level must be due 

 either to faulting or to folding or warping. Minor 



faults, as will be seen, occur in many parts of the 

 region, but no great fault-scarps have been detected 

 such as would account for the abrupt variations. 

 Nevertheless, it can hardly be doubted that Messrs. 

 Tarr and Martin are correct in attributing the 

 variations to faulting rather than to folding. 

 They mention four facts which are opposed to the 

 latter explanation. The lines of deformation ex- 

 tend in too many directions ; the zones of gradation 

 between areas of different degrees of deformation 

 are very narrow, while the intervening areas of 

 uplift are broad ; minor faulting occurs in parts of 

 the region ; and profound faulting is proved by the 

 occurrence of the great earthquakes. 



The straight broken lines in Figure 151 represent 

 the courses of the faults which are inferred from 

 the variations in the changes of level. One of the 

 most remarkable of these faults is that marked A. 

 At its south-eastern end it crosses the head of 

 Russell Fiord just where the uplift changes to 

 depression, and where also there is a change in 

 geological structure ; it also passes exactly through 

 three other areas in which uplift gives place rapidly 

 to depression or to no change of level. To the east 

 of this line there is a straight mountain front with 

 truncated mountain spurs reaching out nearly to 

 the fault-line. Another fault, B, or it may be a 

 continuation of the same fault with a slight change 

 of direction, runs along the east shore of Yakutat 

 Bay, where the mountain front is straight and 

 steep. If this line be continued across . Yakutat 

 Bay, it meets the opposite coast just to the west 

 of the short line of coast in which the uplift changes 

 rapidly from thirty to nine feet. The great uplift 

 of more than forty-seven feet of the west side of 

 Disenchantment Bay, the smaller uplift of seventeen 

 to nineteen feet on Haenke Island and on the shore 

 of the peninsula to the north of it, and the still 

 smaller uplift of seven to nine feet along most of 

 t4ie east side of Disenchantment Bay are explained 

 by two faults, C and D, one on either side of Haenke 

 Island. A fifth fault, E, must follow the course of 

 the main portion of Russell Fiord, for the eastern 

 shore consists of crystalline rocks which were 

 elevated seven feet or more, while the western 

 shore consists of unmetamorphosed rocks which 

 were uplifted by less than two feet. In addition 

 to these five faults, the evidence for which is 

 distinct, Messrs. Tarr and Martin attribute other 

 displacements to three smaller faults, two, F and 

 H, in the islands near Yakutat, and one, G, on the 

 west side of Yakutat Bay. 



(To be concluded.) 



MISTLETOE ON THE OAK. 



As mistletoe \-ery rarely grows on Oak trees, 

 Figures 155 and 156, which are from photographs 

 taken by the Rev. George Sampson, are of con- 

 siderable interest. The tree shown is growing at 



Hackwood Park, the property of Lord Bolton, and 

 now occupied by Lord Curzon of Kedleston. The 

 Oak belongs to the species Quercus pedunculata, 

 and is about fifty feet in height. 



