LIAS OF ENGLAND AND WALES : 
Ammonites bifrons, A. communis, A. Jibulatus, A. heterophyllus, 
A. serpentinus, together with Belemnites subtenuis, B. vulgaris, 
and Nautilus terebratus, may be obtained in abundance. 
The Upper Lias was subdivided as follows by Mr. Dalton: * 
FT. IN. 
Zone of Ammo- f Shales with ferruginous and calcareous no- 
nites bifrons. \ dules (cement -stones) about 38 
f Shales with comminuted shells : yielding 
7/> _ f , Ammonites communis, Gasteropods, &c., 
Zone ot A. com- I , .,, XT , m f , , 
<^ ana with at top a Aucula- or Irigoma- bed, 
with Nucula Hammeri and Trigonia pul- 
[_ chella - - - - -80 
Zone of A. ser- f" Shales with septaria and shelly beds yield- 
pentinus andl ing A. heterophyllus, A. serpentines > Belem- 
A. hetero-\ nites subtenuis; and with Lucina-bed at 
phyllus. I top - - 40 to 45 
f" Shales with two or three bands of argillaceous 
rf P j limestone (Fish and Insect Limestones) : 
Zone or A. annn-4, A . , . ,, r ' 
j . Ammonites anntilatus, A. commnnis, Inoce- 
L ramus dubius, about 8 
The lowest beds (here grouped as the zone of A. annulatus), 
are evidently equivalent to the Basement Beds of other localities; 
while the mass of the higher strata evidently belongs to the beds 
elsewhere grouped as tho zone of A. communis, 
The highest division has yielded but few fossils, and it cannot 
therefore be compared with the beds which Mr. Beeby Thompson 
has grouped in the zone of A.jurensis. The nodular bed at the 
base of the Inferior Oolite series, is suggestive of a break, and 
compares well with the evidence we have throughout the country 
from the neighbourhood of Banbury northwards. Mr. Ussher 
indeed is disinclined to regard the junction as unconformable, but 
it appears most reasonable to conclude with Mr. Dalton, that there 
is evidence generally of transgressive overlap of the Inferior 
Oolite. 
The Basement Beds (clays and shaly limestones), were exposed 
in a brickyard north-east of Navenby station, and there Mr. 
Ussher procured a fragment of an Ammonite, identified as 
A. striatulus ? by Messrs. Sharman and Newton. Such an 
occurrence accords with the evidence obtained in Dorsetshire.f 
(See p. 255.) The higher beds of Upper Lias clay were seen 
near Coleby. Northwards by Brattleby and HarpswellJ there 
are few exposures of Upper Lias ; and onwards by Kirton 
Lindsey and Santon to Winteringham, the evidence shows that 
the thickness is considerably diminished. 
A shaft sunk at Appleby indicates about 70 feet of Upper 
Lias, and perhaps a similar thickness was passed through at Brigg, 
but other bovings tend to show that the thickness may be much 
less, and according to Mr. Ussher little over 25 feet in places : an 
* Geol. Lincoln, p. 33. See also W. T). Carr, Geol. Mag. 1883, p. 164. 
f Geol. Lincoln, p. 180. 
j See Memoirs of W. Smith, p. 96. 
Ussher, Geol. Lincoln, pp. 55, 56, 211. 
