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East of England. The interstratification of regular beds, the occa- 
sional appearance of stratification in the massitself, the juxta-position 
of rounded and angular fragments of various sizes and kinds of rock 
derived from distant mountains, and the frequent capping of gravel, 
indicate some peculiar but similar origin in this deposit of the above 
widely separated regions. Mr. Darwin follows Mr. Lyell in believ- 
ing that floating ice, charged with foreign matter, has been the chief 
agent in its formation ; but he adds that it is difficult to understand 
how the finest sediment was arranged in horizontal lamine, and 
coarse shingle in beds, while stratification is totally, and often sud- 
denly, wanting in the closely neighbouring till, if it be supposed 
that the materials were merely dropped from melting drift ice ; and 
he is disposed to think that the absence of stratification, as well as 
the curious contortions described in some of the stratified masses, 
are mainly due to the disturbing action of icebergs when grounded. 
He believes also that the total absence of organic remains in these 
deposits may be accounted for by the ploughing up of the bottom 
by stranded icebergs, and the impossibility of any animal existing on . 
a soft bed of mud or stones under such circumstances. In confirm- 
ation of the disturbing action of icebergs, Mr. Darwin refers to 
Wrangeli’s remarks on their effects off the coast of Siberia. 
Chiloe.—North of latitude 47° and between it and the southern ex- 
tremity of Chiloe, the author landed at several points, but saw no 
boulders; and he explains their absence by the coast being at a distance 
from the Cordillera, and separated from it by intervening high land. 
At Chiloe erratic boulders, often of great size and consisting of granite 
and sienite, occur in vast numbers along the whole line of the east- 
ern and northern beaches, as well as on the islets. parallel to the 
eastern coast, and on the land at the height of upwards of 200 feet ; 
but the author did not observe any on the western coast at the two 
points which he examined, nor during an excursion of 30 miles 
across the high central portion of the island. Chiloe consists, as far 
as Mr. Darwin ascertained, of mica-slate and volcanic formations, 
extensively bordered, but chiefly on the eastern and northern sides, 
by a horizontally-bedded tertiary sandstone and volcanic grit. On 
the eastern coast, the land is indistinctly: modelled into successively 
rising plains, the surfaces of the upper and the whole thickness of 
some of the lower being in general composed of stratified shingle. 
A few boulders occur in this gravel; and as the shores have been 
extensively denudated, Mr. Darwin infers that most of the very 
numerous blocks on the beaches were originally included in it. At 
the northern end of the island, the granitic and sienitic boulders are 
intermingled, but 30 miles to the southward, the author noticed only 
granite blocks. ‘The parent rock he believes lies in the Cordillera; 
and several of the varieties of granite and sienite at the northern 
end of the island are stated, on the authority of an intelligent resi- 
dent, to form whole’ mountains in Reloncavi Sound, on the opposite 
part of the main land. The larger masses were quite angular, and 
resembled fragments at the foot of a mountain. One block measured 
