stone is that indicated in the diagram of the Northampton section, the true position of the Lincolnshire Limestone is below the Upper Estuarine series, and above the Lower Estuarine series of Mr. Judd's determination ; and to prove, by palseontological evidence, that the former belongs to the Great Oolite, and the latter to the Inferior Oolite group of formations.
Northampton to Kettering*.
In proceeding from Northampton in a north-easterly direction to Kettering (14 miles) en route for Stamford, are passed over (variously, according to the frequent alternations of hill and dale) the several beds of the Northampton section. The Lincolnshire Limestone is not encountered in any place on this line, nor indeed is any peculiarity worthy of comment here, excepting that, at a few miles south of Kettering, a wide tract of the Great Oolite limestone (of which Kingsthorpe offers a typical example) is hidden by overlying beds of Glacial Drift. The occurrence of such Drift-beds is very frequent in the south-eastern and southern districts of Northamptonshire ; but, as my purpose is to treat only of the Oolitic beds, I shall not again allude to these more recent deposits.
Before passing beyond Kettering to districts in which the great expanse of the Lincolnsbire Limestone may be explored, I will revert for a moment to parts of the county, west of that town, in which that formation occurs.
Maidwell, Harrington, and Old.
At a distance of about 10 miles due north of Northampton, in the lordship of Maidwell, is a small patch of the Lincolnshire Limestone, having a spread of about a mile east and west, and half a mile north and south. This patch ranges about half a mile further west than the town of Northampton, and marks the extreme western extension of the area of the formation.
About a mile and a half due east of this, and separated from it by a north and south Liassic valley (through which the Blisworth and Harborough railway passes), is a much larger patch of this Limestone ; which is the uppermost sub-surface rock throughout the greater part of the lordships of Harrington and Draughton.
Immediately beneath the Lincolnshire Limestone of these patches, as shown by the outcrop of the escarpment on either side of the valley, occur the Lower Estuarine and the Ferruginous beds of the Northampton Sand, without the intervention (be it particularly remarked) of the Upper Estuarine Clays, which, as B in the North-
- The route taken by the author in his descriptions and the areal disposition of the several beds he has described can be traced upon the maps of the
Geological Survey — quarter-sheet LII. N.W., revised by Mr. Judd, and the admirable map sheet LXIV., by the same gentleman; but that route perhaps may be more easily followed by reference to the accompanying reproduced diagrammatic map (P1. IX.), which was exhibited by the author on the occasion of the reading of this paper.
