66 Proceedings of Philosophical Societies. (JuLy, 
shell or not ; but the extravascular position of the earthy matter 
of the shell, the separation of the membrana putamuinis in the 
latter stages of incubation, and particularly the singular fact of 
the small quantity of earthy matter, originally existing in the 
egg, remaining unappropriated at the end of the process of in- 
cubation, rendered this opinion very improbable. The. author, 
however, left this poimt to be determined by future observation. 
GEOLOGICAL SOCIETY. 
April 19,—On the Formation of Vallies by Diluvial Excava- 
tion, as illustrated by the Vallies which intersect the Coast of 
Devon and Dorset. By the Rev. W. Buckland, F.R.S. F.L.S. 
V.P.G.S. and Prof. of Geology and Mineralogy, University, 
Oxford. 
The author, on presenting the society with two sectional 
views of the coast on the east of Lyme, and on the east of 
Sidmouth, is led to consider the general causes to which val- 
lies owe their origin, and particularly such as occur in hori- 
zontal and undisturbed strata within the limits of their escarp-+ 
ments. 
Many vallies may be ascribed to the elevation or depression 
of the strata composing the adjacent hills, by forces acting at 
very remote periods from within the body of the earth itself; 
and to similar forces, principally we may refer the high incli- 
nations and contortions of the strata that compose the most 
elevated mountains, and some also of the minor hills. 
Other vallies have been occasioned by the strata having 
been originally deposited at irregular levels, and others to some 
partial slips or dislocations of portions of strata. 
But at different periods of time, intermediate between the 
deposition of the most ancient and the most recent of the 
strata, the irregularities of level arising from the preceding 
causes, have been variously modified by the action of violent 
- inundations, hollowing out portions of the surface, and remoy- 
ing the fragments to a distance. To such inundations, we 
must ascribe the water-worn pebbles of the red marl and of the 
plastic clay formations. 
A cause similar to that last mentioned, has wrought exten- 
sive changes on the surface, however variously modified by 
preceding catastrophes, at a period subsequent to the deposi- 
tion and consolidation of the most recent of the regular strata. 
For rocks of all ages bear on those portions of their surface 
which are not covered by more recent strata, the marks of 
aqueous excavation, and are strewed over with the mingled 
is of the most recent, as well as of the most ancient 
eds. 
When one or more sides of a valley are formed by any of 
those abrupt escarpments, such as usually terminate the out- 
goings of our secondary strata, it is then difficult to say to 
