626 
naturally only a few have been discoveredaccidentally by soundings) still 
rise to different heights above the average level of the ridge but no longer 
attain the surface of the sea. Among these latter we mention three sub- 
marine mountains’) which near the western part of the Azores rise from 
the bottom of the ocean, which has there a depth of about 3000 m., 
to respectively 146, 128 and 88 m. below sea-level. The cause for 
the extrusion of such enormous masses of voleanic material might 
perhaps be sought, in the disruption of the American continent from 
the European-Afriean one with which it formerly cohered. This 
disruption was assumed by Pickering?) and Taytor*) and a plea 
for it is again brought fore by WEGENER on page 68 of his paper 
quoted before. On this supposition the mid-Atlantic ridge would 
in my opinion indicate the place where the first fissure occurred 
and the sima was first laid bare. From this it would follow logically 
that the ridge itself must consist entirely of sima and not of sal, 
as WEGENER assumes or page 69. 
Finally it may be remarked that according to the hypothesis 
put forward in this paper it is not possible that deposits formed on 
the floor of true oceanic regions will ever be definitely raised above 
sea-level and so partake in the building up of continents. In accordance 
with this is what experience had until now taught about the occurrence 
of fossil deep-sea deposits on the continents *). Although their occurrence 
there is much less limited than is generally supposed, they are 
exclusively found in geosynclinal regions, i.e. in parts which once, 
before their folding and forcing up, were deep troughs at a rela- 
tively small distance from the edges of continents and by no means 
true oceanic regions. 
APPENDIX. 
After this. paper had been read, the following contributions to 
our knowledge of the question at issue came to my notice. 
sidence caused by plastic yielding under the influence of gravity, on the contrary, 
is a slow one. Thus, notwithstanding their slow subsidence these islands may 
show well developed cliffs by the action of the waves. 
1) C. Gace. Le. p. 9. 
2) W. H. Pickerina. The place of origin of the moon. Journ. of Geol. XV. p. 
23, 1907. 
83) F. S. Taytor, Bearing of the tertiary mountain-belt on the origin of the 
earth’s plan. Bull. Geol. Soc. of America XXI, p. 179, 1910. 
4) G. A. F. Morencraarr. Over oceanische diepzeeafzettingen van Centraal Borneo. 
Versl. Afd. Nat. d. Kon. Akad. van Wet. Amsterdam Dl. XVII. p. 83, 1909. (On 
oceanic deep-sea deposits in Central Borneo. These Proceedings XVII, p. 141. 
