session 1907 - 1908 . 
Xlll 
Field Meeting, 4th April, 1908. 
LEIGHTON BUZZARD. 
This meeting was under the direction of Mr. G. W. Lamplugli, 
F.E.S., F.G.S., and was held in conjunction with the Geologists’ 
Association, as also were the next two meetings. 
Its object was to examine the Lower Greensand at the 
Shenley Hill sandpits, a mile and a half north-east of Leighton. 
Boulder-clay forms the summit of the hill, beneath it is the 
Gault, and beneath that the Lower Greensand from which sand 
is dug in large pits on the south-east side of the hill. 
The Gault, here a bluish shaly clay, is about five or six feet 
thick. At the top of the Lower Greensand is a thin band of 
iron-grit, and beneath that is a bed from one to two feet in 
thickness described by Mr. Lamplugh as “ ochreous or greenish- 
yellow loamy sand, grit, and breccia; replaced here and there 
by lenticles of pale flesh-coloured or yellowish gritty limestone 
full of fossils.” # That this bed contained fossils was discovered 
by Mr. Lamplugh in June, 1902. In describing it before the 
Geological Society he said: “ The new locality is of especial 
interest in presenting the hitherto-unknown fauna of the highest 
part of the sandy deposits of the district. This fauna exhibits 
anomalous characters which are without parallel in any other 
bed known to occur below the Gault in England. Indeed, if the 
stratigraphical evidence had been less definite, the fossil-band 
would probably have been classed on palaeontological grounds 
with the Upper Greensand.” The fossiliferous blocks afford 
evidence of having been uncovered on the sea-floor, where they 
have been eroded, but the embedded fossils are in perfect 
preservation, rarely showing any trace of abrasion. Brachiopods 
are by far the most numerous, then pectens ; spines of echino- 
derms are rather plentiful; joints of a crinoid and carapaces 
of a crustacean occur ; and many fossils are encrusted with 
Bryozoa. In commenting on this discovery in the 4 Victoria 
History of the County of Bedford’ (vol. i, p. 12), the writer 
remarked : 44 Similar forms of life doubtless occur under similar 
conditions, but the connection is here so close that it leads to 
the inference that the Lower and Upper Greensand must 
somewhere be continuous, the fauna of the Lower Greensand 
migrating under the altered conditions of the Gault period and 
coming back with no further change than would occur in its 
natural process of development and modification elsewhere 
during the deposition of the Gault.” 
Beneath this fossiliferous bed there is a thin band of iron-grit 
very like that above it, then comes a bed of greyish greensand 
with lenticles of pebbly grit, then an irregular bed of iron-grit, 
fuller’s earth, etc., and lastly the beautiful 44 silver-sands,” at 
least fifteen feet thick, for which the pits are mainly worked. 
* 4 Quart. Jo urn. Geol. Soc.,’ vol. lix, p. 288 (1903). 
