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276 : DYNAMICAL GEOLOGY. 

The balance of evidence at present available seems decidedly 
adverse to any theory which would account for ancient and modern 
changes in the relative level of sea and land by variations in the 
figure of the oceanic envelope, but to be in favour of regarding such 
changes as due to movements of the solid crust. The proofs of up- 
heaval and subsidence, though sometimes obtainable from wide areas, 
are marked by a want of uniformity and a local and variable char- 
acter indicative of an action local and variable in its operations, such 
as the folding of the terrestrial crust, and not uniform and wide- 
spread, such as might be predicated of any alteration of sea-level. 
While admitting therefore that to a certain extent oscillations of the 
relative level of sea and land may have arisen from some of the 
causes above enumerated, we must hold that on the whole it is the 
land which rises and sinks rather than the sea.* 
§ i. Upheaval.—Various maritime tracts of land have been ascer- 
tained to have undergone in recent times, or to be still undergoing, 
a gradual elevation above the sea. Thus, the coast of Siberia, for 
600 miles to the east of the river Lena, the islands of Spitzbergen 
and Novaja Zemlja, the Scandinavian peninsula with the exception 
of a small area at its southern apex, and a maritime strip of western 
South America, have been proved to have been recently upheayed. 
In searching for proofs of such movements the student must be on — 
his guard against being deceived by any apparent retreat of the sea, 
which may be due merely to the deposit of gravel, sand, or mud 
along the shore, and the consequent gain of land. Local accumula- 
tions of gravel or “storm beaches” are often thrown up by storms, 
even above the level of ordinary high-tide mark. In estuaries, also, 
considerable tracts of low ground are gradually raised above the tide 
level by the slow deposit of mud. The following proofs of actual rise 
of the land are chiefly to be relied on.? 
Evidence from dead organisms.—Rocks covered with 
barnacles or other littoral adherent animals, or pierced by lithodom- 
ous shells, afford presumptive proof of the presence of the sea. A 
single stone with these creatures on its surface would not be satis- 
factory evidence, for it might be cast up by a storm; but a line of 
large boulders, which had evidently not been moved since the cirri- 
pedes and molluses lived upon them, and still more a solid cliff with 
these marks of littoral or sub-littoral life upon its base, now raised 
that not only are “raised beaches” to be thus explained, but that there are absolutely 
no vertical movements of the crust save such as may form part of the plication arising 
from secular contraction ; and that the doctrine of secular fluctuations in the level of the 
continents is merely a remnant of the old “Mrhebungstheorie,” destined to speedy 
extinction, He is preparing a separate work on the subject, in which he will probably 
explain how he supposes the oscillations in the equilibrium of the oceans to haye been 
caused. See Verhand. Geol. Ieichs. 1880, No. 11. ; 
* The arguments which can be brought forward against the view above adopted and in 
favour of the doctrine that the increase of the land above sea-level is due to the retire- 
ment of the sea, will be found in an essay by H. Trautschold in the Bulletin Societé Imp. . 
des Naturalistes de Moscou, xlii. (1869) part i. p. 1. 
? See “ Karthquakes and Volcanoes” (A. G.), Chambers’s Miscellany of Tracts. 
