92 LIAS OF ENGLAND AND WALES : 
by Dft la Beche, and some of ihe sections have been described by 
W. Boyd Dawkins, H. AY. Bristow, and E. Etheridge.* 
During the years 1871-3, Mr. J. II. Blake was engaged in a 
re-survey of the Secondary tracts in West Somerset, and he then 
revised the boundaries of the Lower Lias, and marked with great 
care the exposures of beds on the foreshore and the numerous 
faults that affect them. 
The strata that are shown, include the zones of Ammonites 
plaiiorbis, A. anrjnlatiis, A. Bucklandi, and A. snnicostutus (or 
A. Turneri). No representatives of any beds as high as the zone 
of A. oxynotus, are known to occur in the area. 
As on the opposite coast of Glamorganshire, the beds, which 
consist of a series of limestones and shales or clays, are by no 
means rich in fossils, though here and there layers occur that 
abound in organic remains, < r these may be met with in patches 
or shoals in otherwise unfbssilifcrous rock. 
Owing to the extent of coast-line, she inaccessibility of certain 
portions, and the numerous faults and undulations, it is difficult to 
determine the limits of the several divisions, and to measure with 
accuracy the thickness of the beds. Here and there the Rhsetic 
Beds or New Red Marls form the mass of the clink 
AVe find in the lowest division (zone of A. jtl(inorMs) that lime- 
stones arc not so prominently developed as at Street and at 
Lavernock, Ivt these beds are surmounted, as at Lavernock, by a 
grey marl :"! vision that may be grouped with the zone of 
Ammonites u.ifjulatus. Siiil higher we come to the main mass of 
blue limestones, which here, as at Dunraven and eastwards on the 
Glamorganshire coast, belongs to the zone of Ammonites Buchlandi. 
Above these beds there is again a considerable thickness of grey 
marls with subordinate bands of argillaceous limestone. These 
represent the zone of Ammonites semicostatus, and may perhaps 
include portions of still higher beds, for west of Kilve I obtained 
a specimen, doubtfully referred by Messrs. Sharman and Newton 
to A. densinodus. 
The following is the general succession of the strata seen along the coast of 
West Somerset : 
FT. IN. FT. IN. 
f5. Dark grey shaly marls with thick bands 
of argillaceous limestone, and , near the 
base, a conspicuous band of paper- 
shales. Seen in cliffs above the cave 
east of Kilve Pill, by Kilve Farm and 
westwards to Quantockshead ; also J>40 to about 45 
near Donniford Kiln, by the Bathing 
Cove at Watchet, and to the east of 
Blue Anchor. Large Ammonites, A. 
semicostatus, A. Turneri, Curdiina, 
[_ Pentacrinus. 
* Vertical Sections (Geol. Survey), Sheet 47, No. 6 ; Ktheridge, Froc. Cottesw. 
Club, vol. vi. p. 35; Dawkins, Quart. Journ. Geol. Soc., vol xx. p. 397. 
