210 
LOWER OOLITIC BOOKS OF ENGLAND : 
eroded, some of them being slightly encrusted Avith calcareous 
matter." His lists evidently include species not only from Great 
Ponton, cutting but also from the shallow cuttings, between the 
two larger ones. Among the species of Gasteropoda the following 
have been recorded* : 
AciEeonina glabra. 
Alaria hamoides. 
pontonis, 
Amberleya gemmata. 
Ataplirus Belus. 
discoideus. 
Bourgnetia (Phasianella) 
gang. 
pontonis. 
ele- 
Brachytrema binodoaum. 
subvaricosum. 
Ceritella lindonensis. 
Sowerbyi. 
Cerithium Georgei. 
limaaforme, var. pontonis. 
Cylindrites tnrriculatus. 
Exelissa pulchra. 
Littorina Phillipsi. 
Monodonta Lyelli. 
ITerinaea bacillus. 
cotteswoldijB. 
pseudopunctata. 
(cf.) Stricklandi. 
subglabra. 
Onustus ornatissimus. 
Patella. 
Eissoina obliquata, and 
parcicostata. 
Trochotoma extensa. 
Trochus Ac is. 
Ibbetsoni. 
monilitectus. 
The Lincolnshire Limestone has been well exposed at Denton, 
and from the lower beds Malaptera Bentleyi has been recorded. 
From the neighbourhood of Grantham to Ancaster, the thick- 
ness of the Lincolnshire Limestone appears to increase to a total 
of about 100 feet, while the underlying Lower Estuariue Beds 
and Northampton Sand, have been estimated to have a thickness 
of 40 feet at some localities, but usually this does not exceed 20 
or 30 feett 
A good section of the lower beds was noted as follows, by 
W. H. Holloway, in Syston Park, N.E. of GranthamJ : 
FT. IN. 
Lincolnshire J Soil and rubbly oolite - - 3 8 
Limestone. \ Sandy limestone - - - 1 2 
Lower Estuarine J Sandy marls ; red, white and greenish 
Series I san ds; white, purplish, black and 
I grey clays - - - - 12 6 
The sandy limestone, no doubt, represents the Collyweston 
Slate : a similar bed was shown in the railway-cutting west of 
Ancaster railway-station. There also the details were measured 
by Holloway. The Lower Estuarine Beds consist of alternations 
of white sands and laminated clays, as in the above section, and 
attain a thickness of 7 or 8 feet ; they rest on a ferruginous and 
sandy rock, with thin calcareous bands, exposed to a depth of 
4 feet. This last-named bed represents the Ironstone of the 
Northampton Sand, and rests on the Upper Lias Clay. The 
thickness of the Northampton Sand at Belton Ashes was proved 
to be 15 feet. 
* Moms, op. cit., p. 327 ; see also Hudleston, Gasteropoda of the Inferior Oolite, 
pp. 72, &c ; Hudleston and Wilson, Catalogue of Jurassic Gasteropoda, 183J. 
t Sharp, Quart. Journ. Geol. Soc., vol xxix. p. 266 ; Morris, Geol. Mag., 1869, 
p. 103 ; Jukes-Browiit, Geol. S.\V. Lincolnshire, p. 45. 
Geol. S W. Lincolnshire, pp. 50, 51. 
