SCIENTIFIC SUMMARY. 
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the remaining marine drift, and left the island with its present contour. 
After the raising of the great north-east and south-east ranges, first coast- 
ice flowed east and west, and afterwards the glaciers followed in a similar 
direction, and thus perhaps the origin of the boulders, those which are so 
curiously perched being due rather to the latter than to the former. Thus 
it would seem that icebergs and coast-ice preceded glaciers, but to say what 
might have come before the former of these agents would only be diving 
deeper into the depths of a sea of speculation/’ 
The Ash-showers of Iceland. — Professor Nordenskiold, in the “ Geological 
Magazine” (June), has an important paper on this interesting subject. 
From this we extract the following : — 11 Our knowledge of these eruptions, 
however, unfortunately is not as yet founded on any scientific examination ; 
and it is perhaps the less necessary to repeat here the interesting accounts 
of those grand phenomena that have appeared in the newspapers, as I expect 
to have an opportunity another year of returning to the subject, since the 
region will probably be visited next summer by a distinguished geologist, 
well acquainted with the natural history of Iceland. I will only mention 
that the eruption began in the month of Dec. 1874, and then continued with 
shorter or longer intervals from numerous craters situated in the interior of 
the country, partly on Dyngjufjall, partly in the northern part of Vatna- 
jokul, or in the region between these enormous glaciers and the great snow- 
clad volcano Herdabreid. The most plentiful ash-rain on Iceland itself took 
place in consequence of an eruption which began at the place last mentioned 
on March 29, and the ashes which fell in Scandinavia probably belong to 
the same point of time, in which case less than twenty-four hours was 
required for carrying the ashes from Iceland to Scandinavia ; that is, for 
their passing over a distance of 200 Swedish miles, or 2,000 kilometres. 
Geological science has recorded many accounts of the fall of volcanic ashes, 
where the ashes have been carried by the wind to very remote regions ; 
among others that ashes had already been carried, a couple of centuries ago, 
from Iceland to Bergen, on the west coast of Norway ; but no example of 
so extensive a spreading of volcanic ashes with the wind, as from Iceland to 
the east coast of Sweden, is previously known. On Iceland the ashes fell 
in such quantity that at some places they covered the ground to a depth of 
6 inches, and destroyed the pastures. The cloud of ashes was for several 
hours so close that the sunlight could not penetrate it, and lights required 
to be kindled in the middle of the day. The ashes must also have fallen in 
considerable quantity in the sea between Iceland and Norway, and on its 
bottom there are doubtless found places where the remains of such falls 
collect during centuries without any considerable mixture of foreign matter. 
Here must be formed thick beds of volcanic ashes, which in the course of 
geological ages gradually harden together, and are metamorphosed to rocks 
of nearly the same composition, and therefore also strongly resembling those 
which in molten form burst forth from the interior of the earth ; and we 
have here, doubtless, the key to the extension over boundless regions of the 
earth of stratified so-called volcanic rocks, a circumstance to which I have 
already long ago drawn attention with reference to the occurrence of plu- 
tonic rocks regularly stratified in the polar regions.” 
American Earthquakes in the First Quarter of the Year. — In a good 
