TIIK WAKE OF THE DORA 



i'liuto by Joiiu i;. I'll 

 THROUGH THE Fl.OATTXG I'l'MICE 



Fishermen reported a field of pumice in Shelikof Strait dense enough to support a man. 

 The pumice consists of rhyolitic glass, with a small amount of crystals of feldspars and 

 pyroxenes. It is a lava which solidified at a time when it was giving off gases, and is con- 

 sequently of a porous and spongy texture, which makes it so light that it will float. 



boat. Even this was invaded by the float- 

 ini^ rock, vhich jammed tight arotmd and 

 carried our boat with it when it moved^ 

 in spite of two anchors and two pieces 

 of pig iron down, and forced us to make 

 fast to a projecting cHff. The floating 

 pumice was twelve inches thick alongside 

 the boat and possibly was much thicker 

 in the center of a large field. Fishermen 

 reported a pumice field dense enough to 

 su])port a man in Shelikof Strait. 



The pumice, once in the sea. will drift 

 around until it is thrown high upon some 

 beach, is ground to powder, or finally 

 becomes waterlogged and sinks. 



EFFECT ().\ LIFE 



The efifect of the eruption on whatever 

 vegetation clothed the flanks of the vol- 

 cano was certainly annihilation. The 

 position of the death-line around the 

 mountain is not known, but it came prac- 

 tically down to the sea, 15 miles from 

 the crater at Katmai. The conditions 

 under which the bushes in Katmai Val- 

 ley were killed is uncertain, but a hot 

 blast like that of Pelee is stiggesleil. 

 The brush is living in Amalik Bay, no 

 farther from the volcano, and where the 



fall of ash was twice as great as at 

 Katmai. 



The efifect on the vegetation of Kodiak 

 and Afognak islands was apparently 

 only that of burial. \\'here the ash was 

 washed ofif, even after many weeks, the 

 grass soon came up, and apparently 

 showed the effects of no other injury 

 than that which would be caused by a 

 similar burial imder any other material. 

 The stronger-stemmed plants, especially 

 the fireweed, lui)ines, and some of the 

 grasses, forced their way up through the 

 cracks in the ash, and even through its 

 solid mass where the thickness was not 

 too great (see page t8o). 



The finer dust stuck to the trees, espe- 

 cially to the spruces, causing a wintry- 

 looking scene which lasted all summer. 

 This fine dust does not wash or shake 

 oft' readily, and probably will cling to the 

 more sheltered spruces for manv years. 

 The dust from the eruption of Redoubt 

 in January, 1002, was still lodged on the 

 sjiruces along T.ake Clark in the summer 

 of KJ09. It api)arently had a serious ef- 

 fect upon the trees, only the to])s and 

 the outer tips of the boughs showing a 

 healthv growth. This same after effect 



I7Q 



