VOL. XVI. (3) EXCURSION—SHEPTON MALLET, FROME 225 
millions of years later, the quarrymen came to work the Carboniferous 
rocks, they removed the Limestone, but left the soft in-fillings of 
Rhetic, Liassic or Inferior-Oolite rocks as useless, and therefore 
standing up in the form of walls or ‘‘ dykes.” 
In the quarry on the opposite or north side of the road is a very 
fine “dyke,” from the sides of which numbers of teeth and scales of 
Rheetic fish may be collected. In a hollow in the quarry-face is seen 
White-Lias rock mixed with clay in which are embedded sub-angular 
masses of chert and extremely well-rounded pebbles of Carboniferous 
Limestone, covered with specimens of the little Rhzetic shell Démyodon 
intusstriata (Emmerich). The sub-angular blocks and rounded pebbles 
have been derived from the Carboniferous Series in the neighbour- 
hood, rolled about, and encrusted with little shells in the far-off 
Rhetic Epoch before ever the Lias of the Vale of Gloucester and the 
Oolite of the Cotteswold Hills were formed. 
Rejoining the brakes, the route followed was over Nunney 
Common and Whatley to Mells. By the roadside near Whatley 
Church were some Sarsen Stones or ‘‘ Grey Wethers,” which are 
not at all uncommon in this neighbourhood, there being a considerable 
number of them at the foot-bridge near Nunney Castle. Sarsen 
Stones are portions of a once incoherent deposit of (Palzogene) sand 
that have become coherent by the infiltration of a siliceous cement, 
and while the uncemented portions of the deposit have been removed, 
these have remained—even during the time of removal of a consider- 
able thickness of subjacent rock. 
After tea at the Talbot Hotel, Mells, the Members drove through 
Elm to Hapsford Mills at the entrance to Vallis Vale. 
Vallis Vale is well known for its romantic scenery and marked 
geological unconformities. In most places the Doulting Stone sub- 
division of the Inferior Oolite rests directly upon the planed, bored, 
and oyster-covered surface of the highly-inclined Carboniferous Lime- 
stone; but at the northern end, where the planed surface of the 
limestone is inclined downwards, and becomes more and more widely 
separated from the Inferior Oolite, intervening beds appear. The 
first to thus come in is the Rhetic Series, which may be studied near 
Hapsford Mills. In Vallis Vale the covering of Jurassic rocks has 
been cut through by the stream which now meanders in an alluvial 
flat bordered by steep quarried cliffs of Limestone capped with Oolite. 
The Members first proceeded to the place where the two streams 
join in Murdercombe, to study the classic section, showing Oolite 
resting upon Carboniferous Limestone, which was pictured by Sir H. 
de la Beche.* A number of fossils was collected, and the planed, 
oyster-covered and bored surface of the Carboniferous Limestone was 
the subject of special comment (PlateXXV.) Regret was expressed 
that the extensive quarrying operations were so speedily destroying 
the picturesqueness of one of the most beautiful and romantic parts of 
Somerset. 
1 Mem. Geol. Surv., vol. 1 (1846), p. 289. 
