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rests directly on the tuff of the mud flow. Moreover this stratified 
ash covers a more extended area and on the South slope of Mt. 
Katmai there lies upon this ash a cold mud flow. This cold mud flow 
is explained by Grices as the result of heavy rains, with which 
explanation I fully agree. The cold “lahars’ from the Smeru volcano 
(Java) which brought about the notorious disaster of Lwmadjan, 
are one of the many parallels to this cold mud flow (lit. 11). 
Grices seems to be unaware of other mud flows from voicanic 
material than those caused directly by rainwater or by the thaw 
water from glaciers’), but there are sufficient indications in the Katmai 
region that the glaciers did not melt to any great extent in connection 
with the explosion of Mt. Katmai. Grices has estimated the cubical 
capacity of the tuff of the great hot mud flow as one cubic mile 
(lit. 5 p. 1387), or, in other words, as 4096 million cubic metres. 
To hold this quantity of solid material in suspension he esteems 
necessary at least as much water, i.e. at least 4096 million cubic 
metres, and he has not succeeded in finding a source for this enor- 
mous quantity of water. 
Moreover he has been unable to account for the fact that the 
great mud flow must be older than the ashfall, although according 
to his views the ash deposited as subaérial sediment was caused by 
the explosion of Katmai. 
If the strata of ash lay below and the mud flow rested upon 
it, it is assumed by Griaces that the matter is capable for simpler 
explanation, but this is by no means the case, for the reason that 
the great mud flow was hot. Since he could not find water coming 
from above Griees has concluded that the mud which formed the 
great mud flow welled up from within the valley itself. His view is 
that the mud welled quietly up without any explosive action through 
several fissures in the floor of the valley. 
Grices is well aware that he has imagined a voleanologic pheno- 
menon wholly unknown to science and declares that he is unable 
to suggest any hypothesis to account for the mecanism which brought 
about the great mud flow. 
His conclusion he has talked over with some students of volcanism 
in America, who after the most violent opposition have accepted, 
as he says, his interpretation as the only one in harmony with the facts. 
From this it would appear that the numerous publications on the 
Klut voleano (lit. 7—15) are not well known in America. 
The nature of the outbreaks of the Klut volcano, which is known 
1) These “mud flows are known in Iceland by the name „jökulhlaup” 
(lit. 18 p. 171). 
