Great Oolite . . 

 Inferior Oolite 



Mr. S. Sharp on the Oolites of Northamptonshire. 75 



T o . ~ ,., f Lower Estuarine Beds 1 Northampton 



Infenor Oolite . . . . | Ferruginous Eeds j gand . 



Upper Lias Clay. 



And this section, with the successive superaddition of Great Oolite 

 Clay, Cornbrash, Kelloway Kock, and Oxford Clay, is continued 

 due east across the country to the valley of the Nene, and on into 

 Huntingdonshire. 



Upon the same Ise escarpment, about a mile north-east of Ket- 

 tering, the thin end of the wedge of the Lincolnshire limestone is 

 seen to come in; and this sequence, for the first time, is pre- 

 sented : — 



' Limestone. 

 Upper Estuarine Clays. 

 Lincolnshire Limestone (very thin). 

 Lower Estuarine Beds | Northampton 

 Ferruginous Beds .... J Sand. 



Upper Lias Clay. 



The same sequence, with the occasional superaddition of the Great 

 Oolite Clay, was shown to be repeated upon the western escarpment 

 of the Ise, at Glendon, Barford Bridge, near Eockingham, at Weekly, 

 and at Geddington (the Lincolnshire limestone increasing in thick- 

 ness at every advance), and to occur over and over again upon in- 

 numerable escarpments in the counties of Northampton, Butland, 

 Lincoln, and York, offering unmistakable and incontrovertible evi- 

 dence of the true strati graphical position of the Lincolnshire lime- 

 stone. 



The author described the section in the ancient quarries at Weldon, 

 whence is obtained the highly reputed freestone of that name. He 

 exhibited a diagram of the horizontal section from Eockingham, on 

 the Welland valley (which marks to the north-west the line of divi- 

 sion between Northamptonshire and Eutland), through Weldon, by 

 Oundle, and across the Nene valley into Huntingdonshire. It was 

 shown by this diagram that, although the Lincolnshire limestone has 

 a thickness of some 30 feet at Weldon, it thins out very rapidly 

 eastwards, being nowhere found within three miles of Weldon, and 

 being altogether absent from the Nene escarpment at Oundle, which 

 presents, with this exception, the whole series of beds from the 

 Oxford Clay to the Upper Lias Clay inclusive. 



The author successively described sections in the Lincolnshire 

 limestone : — at Kirby, where the equivalent of the Colley weston slate 

 is quarried, this!being the extreme western point at which it has been 

 found ; at Deene, Wakerley, Morcot (where the whole series from 

 the Cornbrash to the Upper Lias inclusive occurs, the Lincolnshire 

 limestone attaining to a thickness of 60 feet), Ketton (where the 

 famous Ketton freestone is quarried), and Colleyweston. At the 

 last-named place the well-known calcareo-arenaceous slate has been 

 quarried for more than 350 years; and the numerous quarries 

 occupy an area exceeding a mile in diameter.* Here everywhere 

 may be noted the position of this slate-bed, passing the Lincolnshire 

 limestone series, and immediately overlying the Lower Estuarine 

 Sands. 



