INFERIOR OOLITE: ROCKINGHAM FOREST. 
193 
Prof. Judd remarks that " A long narrow inlier of the North- 
ampton Sand is seen in the upper part of the valley of the Willow 
Brook, near Dene, Bui wick, and Blatherwycke, but there are 
seldom good exposures of the strata. At Dene brickyard we have 
the following section : " 
Lincolnshire 
Limestone. 
Lower Estuarine 
Series and 
Northampton 
Sand. 
Upper Lias Clay. 
Marly limestone - - 1 to 
Whitish caclareons sands 
Hard, blue-hearted, sub-crystalline 
limestone .... 
Brownish, calcareous sand, becoming 
indurated into stone at its base 
Hard and compact, coralline limestone, 
full of NerinoBa, with partings of 
clay - 
Irregular bed of siliceous concretions 
with mammillated surfaces below. 
This bed is intensely hard ; between 
its laminae are contained numerous 
plant-remains ; it appears to be the 
representative of the Collyweston 
Slate - 
Irregularly stratified and false-bedded, 
variegated sand - - 6 to 
Black, carbonaceous, sandy clays, with 
nodules of pyrites, and many frag- 
ments of wood converted into the 
same mineral .... 
Bed of hard sandstone of a dark-grey 
colour (" kale " of the workmen) 
Clay, similar to bed above, but lighter 
coloured and more sandy 
_Sandy ironstone (dug in a well) 3 to 
FT. 
2 
IN. 

6 
3 
8 
6 
" This section is of great interest as presenting another type 
of the Northampton Sand, namely that in which a great part of 
the formation is represented by beds of dark-coloured clay. 
These beds have in some instances been mistaken for the Upper 
Lias, and have, indeed, been sometimes mapped as such. A close 
inspection, however, soon convinces the observer that the resem- 
blance is a very superficial one, and is confined almost entirely to 
colour. The clays in question are totally wanting in the tenacious 
character of the Upper Lias, and indeed they are composed quite 
as largely of arenaceous as of argillaceous materials? ; their dark 
colour appears to be due to the large quantity of organic (vege- 
table) matter which they contain."* 
Slates are occasionally worked to the south of Dene Wood, 
and they were formerly worked west of Kirby Lodge to the 
north. A section which I saw in 1889, by Dene Wood, was as 
follows: 
FT. IN. 
Boulder Clay - - 2 to 4 
Lincolnshire f Compact brown gritty limestone used 
Limestone. \ for road-metal - - 3 
* Judd, Geol. Rutland, pp. 101, 102, 152 ; Sharp, Quart. Journ. Geol. Soc., vol. 
xxix. p. 236. 
B 75928. N 
