1873.] SHARP OOLITES OF NORTHAMPTONSHIRE. 229 



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 pecu- 

 liarity 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 Northamp- 

 tonshire ; 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. 



Maid well, 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 exten- 

 sion 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 ; wbieh 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 Eerruginous 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 disposi- 

 tion 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 dia- 

 grammatic map (PL IX.), which was exhibited by the author on the occasion of 

 the reading of this paper. 



