60 LIAS OF ENGLAND AND WALES : 
the species has actually been obtained at Lyme Regis ; but Dr. 
Wright records it from the Hard Marl, and from the underlying 
clays and shales down to the " Grey Ledge/' and have obtained 
specimens from the foreshore. A. Bonnardi is recognized by 
Messrs. Sharraan and Newton from this locality, and this is a 
form closely approaching A. Turneri. Specimens of both species 
of Ammonites are frequently partly enveloped or replaced by 
iron-pyrites ; and most of them have been found on the beach 
or among the fallen blocks near the northern end of the Church 
Cliffs. Specimens thus mineralized would not have come from 
the Hard Marl, but might occur in any of the shaly strata. A 
block of limestone purchased from Mrs. Dollin, of Lyme Regis, 
contains A. Bonnardi and A. Turneri ? Dr. Wright records 
A. Bonnardi from the beds (above mentioned) which he groups 
in the zone of A. Turneri; but I have not found it in situ. 
It occurs also higher up in the series. Mr. Day, indeed, con- 
sidered that A. Broolici was the local equivalent of A. Turneri, 
forms regarded by Dr. Wright as very closely allied; but A. 
Brookei occurs in a higher horizon, in the zone of A. obtimnx. 
Under these circumstances it will be best to regard the upper 
portion of this Blue Lias series rather as the zone of Ammonites 
semicostatus than of A. Turneri, for the former species is found 
often in abundance on the same approximate horizon in other 
parts of England and lias more generally been adopted as the 
zonal Ammonite.* 
The Blue Lias series of Lyme Regis thus includes the zones of 
Ammonites planorbis, A. angulatus, A. Bucklandi, and A. scmi- 
costatus'- an arrangement that fits in well with other parts of 
England, as it includes the main mass of the Lower Lias lime- 
stones, where these are well-developed. 
The Hard Marl, and the West Rock, an iron-stained cement- 
stone that occurs in West Cliff at a higher level in the clays 
above, are said to make a superfine cement when mixed together. 
The following is a detailed account of the Blue Lias series of 
Lyme Regis, with the local names applied to the beds by the 
workmen : f 
FT. IN. 
Division E. 
with 2 beds of 
marl and lime- 
HARD MARL or TABLE LEDGE. (" INDU- 
RATED MARL," of De la Beche.) Grey marl. 
Ammonites semicostatus [A. Turneri}, Avicula, 
stone : about 
1 Q foot 
incequivalvis, Rhynchonella calcicostn (= vari- 
ly ieet. 
Representing 
zone of 
Ammonites 
semicostatus. 
Seen in Church 
Cliffs, West 
r*MPP nr*A 
abilis of Wright) 
SAURIAN BED. Shale. [Ichthyosaurus com- 
' munis, I. platyodon, Am. semicostatus, Rh. 
caldcosta'] - 
SPLIT LEDGE or FISH BED. Shaly limestone, 
breaking into pencil-like slabs. [Am. Turneri, 
A. semicostatus] - - 
3 
12 

6 

4 
\Ain, ana 
Marl and shale with limestone-nodules - 
3 
8 
Pinhay Bay. 
* Ussher, Geology of Lincoln (Mem. Geol. Survey, Sheet 83), p. 16. 
f A detailed section was published by Dr. Wright, Quart. Journ. Geol. Soc., 
vol. xvi. pp. 401, &c. The species included in square brackets are given on hi? 
authority, but it is not possible to correlate all the particular heds he enumerates, 
with those above noted. 
