64 PROCEEDINGS COTTESWOLD CLUB I9OI 
far as to submerge the lowest tract of land which lay 
between the great salt lakes and the wide spreading 
southern ocean.” But before this barrier had disappeared, 
the level of the water of the Keuper Sea may have been 
greatly reduced by evaporation,’ with the result that a great 
part of the conglomerate, once formed beneath the waters 
of the inland sea, would now be considerably above water, 
without any movement of elevation. Ramsay’ considered 
it probable that after the water-level had been thus reduced, 
the inland sea gradually became filled with water, perhaps 
by increase of rainfall. The “ Dolomitic Conglomerate” 
would hardly be consolidated when exposed to sub-aérial 
denudation, and hence would be subject to removal in 
places, especially if a pluvial period had set in.” 
Slowly, however, the Mendip area sank, and the junction 
with the Rhetic ocean seems to have been effected when 
the inland sea was almost filled with sediment. Deposition 
in Rhetic times was extremely slow, the paucity of 
sediment being manifested in the “ bone-bed.” The “ bone- 
bed” at Milton Lane included angular limestone 
fragments.° 
In the Harptree district occurs a very remarkable 
set of arenaceous and cherty beds of Rheztic and Lower 
Lias age. The lower strata consist of hardened reddish 
brown micaceous sandstone with Pudllastra arenicola.* 
The exact age of certain beds in this district is difficult 
to determine, and also the precise junction of the Rhetic 
and Liassic stages. The sandy conditions point to a 
marginal deposit derived from the Old Red Sandstone. 
The “bone-bed” in places was formed during a slight 
elevation, as seen at Aust Cliff; and a similar movement 
1 A. J. Jukes-Brown, “ The Building of the British Isles” (2nd Ed., 1892), p. 222. 
2 Quart. Journ. Geol. Soc., vol. xxvii., p. 196. 
3 Quart. Journ. Geol. Soc., vol. xxii., p. 93. 
4 Mem. Geol. Surv., “ Jurassic Rocks, etc.,” (1893), vol. iii., p. 123. 
OE EE EE 
