1870.] SHARP—NORTHAMPTONSHIRE OOLITES, 371 
It will have been observed that in “‘ The Roylands,” bed no. 3, 
much wood, and slabs ripple-marked, have been found. These, I 
take it, indicate estuarine or littoral conditions during the period of 
deposition. 
In the “ White Pendle,” no. 5, we have a prominent example of 
the limestone and slaty beds which I have found to occur at different 
points over a considerable area in the same position in the general 
section of the district. The calcareous nature of these beds, and the 
slaty character of the so-called “ Colleyweston Slate’ (no. 5, 6), and 
indeed of the Colleyweston Slate itself, I consider to be attributable 
to accidental and local causes, as are also, within more limited areas, 
the remarkable variations upon the same horizon in beds described 
in former sections; but I cannot but think that the persistency of 
this limestone band over a considerable local area indicates a pas- 
sage in time, an alteration in the depth of the aqueous bottom, and 
possibly a change to more marine conditions, which raise that band 
above the synchronous and patchy variations so frequent in the 
beds of D. This persistency, although sometimes the slate bed and 
sometimes both beds have been wanting, has induced me, for my 
own guidance, to adopt these beds as a mark of separation between 
what I consider to be the Middle Division (D) and the Lower Di- 
vision (EH) of the Northampton Sand. 
At a distance of a few hundred yards from this Duston “ Old” 
pit, is the “Old Slate-quarry Close.’ Here a stone-pit (v) was 
opened a few years since, which exposed some of the old workings, 
carried on, at some unknown distant time, for the obtaining of slate 
alone. ‘The old process was that still sometimes adopted at Colley- 
weston, and called ‘‘foxing.” Shafts were sunk, and the slate was 
extracted from beneath the overlying beds by means of adits. 
The section of this pit has a less elevation than that of the « Old 
pit; and the beds are imperfect continuations of those of the latter, 
exhibiting traces of both natural and artificial disturbance. The 
characteristic and crowded zone of Astarte elegans of the “ Rough 
Rag,” no. 5, of the last section, is continued into this section. I 
have also found this zone in two other sections in the Duston area, 
presently to be described, severally a mile and a half and two miles 
from this point, and also at the Harlestone pits, at v', more than a 
mile to the north-east of Duston “Old” pit; so that this Astarte- 
elegans zone extends over an area at least three miles in diameter in 
one direction. 
I have to thank the proprietor of these two stone-pits (Mr. Samuel 
Golby) for information communicated by, and fossils received from 
him. 
In a small pit temporarily opened at a short distance east of v, I 
obtained from the limestone-bed no. 5a, a very perfect tooth of 
Megalosaurus. 
About a mile south of the ‘‘ Old”’ Duston pit (at w), upon the es- 
earpment of the hill overlooking the wide valley, some four miles in 
breadth, traversed by the southern branch of the river Nen, and by 
the main line of the London and North-Western Railway, (in which 
