The Continental Platform 
a consideration of the relations of the formations in the British Isles is supported and strengthened by that 
drawn from the American side of the Atlantic ; namely, that this part of the great ocean was in the condi- 
tion of a land area when the bordering lands were submerged—a conclusion which is incompatible with 
the theory of permanence of land and sea. We are, therefore, forced to the inference that the relations of 
land and sea at the present day are the result of interchanges of land and sea, and movements of the 
crust itself. 
Such changes are quite intelligible when we recognise those which have taken place in Tertiary — 
times in the Alps, and other mountain ranges where Eocene and Oligocene beds of marine origin and 
containing fossils are found at elevations of thousands of feet above the ocean. 
In the succeeding Pliocene period began the general uprise of the land and retreat of the sea, 
accompanied by increase of cold conditions which culminated in the Glacial Period. On this account, 
Pliocene strata are only found within comparatively short distances of the coast; but are rich in 
representatives of the fauna and flora of the period.’ 
Continental Attraction. — Although we have necessarily taken the surface of the ocean as the 
standard of comparison for depths at any place, it is not to be supposed that this is constant over the 
whole globe; on the contrary, it is well understood that the continental lands exercise an important 
influence on the level of the surface as measured by its distance from the centre of the globe. The 
land attracts the sea, and the sea attracts the land; but as the former is (so to speak) immovable, the sea 
is drawn towards the land, and consequently the waters rise above the normal level as they approach 
the coast; while the water being withdrawn from the central parts of the ocean, the surface falls. 
This is a physical result which the researches of Professor Sir G. G. Stokes, Fischer, and Hann have 
established. Suess lays stress on this result, which is determined by the difference of the oscillations of 
the pendulum in 24 hours, on an oceanic island and on the margin of a continent.” 
An important physical result of the lowering of the surface of the ocean is, that some of the islands, 
now rising into land, owe their presence as such to the withdrawal of the ocean water, and others have 
their areas very much enlarged thereby. The present distribution of the volcanic islands of the Pacific is 
largely affected by the above results of continental attraction. There is an apparent discrepancy between 
the views of the above-named mathematicians and those of Lyell, as will be found from the following 
quotation : “There is no evidence from human experience of a rising or lowering of the sea’s level in 
any region ; and the ocean cannot be raised or depressed in any one place without its level being changed 
all over the globe” (Student's Elements of Geology, p. 48; edit. 1874). But this does not affect the 
question of the results of continental attraction in determining the level of the sea above or below the 
mean ellipsoidal, or geodetic, surface. Fischer’s formula is found by taking the difference between the 
observed and calculated observations of the seconds pendulum at any station or stations, and multiplying 
the result by 122, which gives the rise of the water surface above the mean ellipsoidal surface in metres. 
We must concur with Fischer as a general result that the ellipsoidal surface will intersect the actual 
surface in the ocean outside and beyond the margins of the continents. 
1 Prestwich, Geology, vol. ii. p. 425. 
2 Das Antlitz der Erde, vol. i. p. 2; trans. by Miss H. B. C. Sollas. 
