102 Morris — Oolites of Northampton, ^c. 



and Cheltenham, which are known as Inferior Oolite. These forma- 

 tions change from the coarsely Oolitic character, through all shades, 

 to the finest sand, sometimes brown and ferruginous, sometimes 

 white, with yellow bands (Arbury Hill). Ammonites MurchisoncB is 

 certainly wanting, but Pecten personatus, Clypeus sinuatus, Pliola- 

 domya obtiisa, and others are chiefly found." 



Oppel refers these beds to the same period,^ and Dr. Lycett" also. 



In the Northampton area the White Oolites overlying the ferru- 

 ginous bed do not appear to contain, in their lower beds, many 

 forms of Mollusca belonging to the Inferior Oolite, as do those 

 limestones to which we shall presently allude in the neighbourhood 

 of Stamford. Species of Astarte, Nerincea, and Trigonia, are found, 

 and in the upper beds Pholadomyce abundantly occur, frequently 

 occupying the position in which they originally lived, as may be 

 well seen in the quarries on the Moulton-road. 



A somewhat similar arrangement of the same rocks may be found 

 in ascending from the Wellingborough Station to Wollaston, where, 

 however, beds equivalent to the Forest Marble occur, Terebratula 

 digona being found in tolerable abundance, associated with other 

 Great Oolite forms. 



The next point for consideration is the position of the Collyweston 

 Slates, which have been extensively worked in the neighbourhood of 

 Stamford, since the time of Henry VII. Quarries may be seen at 

 Wittering, Collyweston, Easton, Dene, and Kirby. 



The geological position of these slaty rocks can therefore be 

 clearly seen in many localities. 



Thus, in the Valley of the Welland as of the Nen, the ferruginous 

 Sand-rock before noticed overlies the Lias, and is covered by sand 

 and concretionary calcareous Sandstones, which split horizontally 

 after exposure, thus forming the so-called Collyweston Slates. 



Overlying these are a series of cream-coloured marly limestones, 

 as well as Oolitic rag-stones of some thickness, as seen in the quarries 

 near Stamford, where they yield the so-called " Stamford marble," 

 also at Barnack, Casterton, G-eeston, Ketton, and Collyweston, whilst 

 further west at Morcot, similar compact limestones overlie slaty 

 rock containing Lingida. It is these Lower Limestones which con- 

 tain a series or group of Mollusca, which are considered in part 

 to be characteristic of the Inferior Oolite, associated with similar 

 species of Cycads and Ferns {Pecopteris polypodioides) , as occur in 

 the Oolitic shales of Yorkshire, whilst the Upper White Limestones 

 include a fauna in which those forms are more rare. 



In some quarries, as near Ketton, a line of separation is marked 

 in the Oolitic rocks by definite perforations caused by LitJiodomi, 

 which clearly indicate a period of arrested deposition in this old sea- 

 bed, during which these moUusks lived and inhabited the surface of 

 the subjacent rock, already partly consolidated. 



It is above these upper beds that the laminated Clays and Shales 

 containing plants, with one or two species of Cyrena, showing their 

 probable fluvio-marine condition, occur, as seen at Ketton and 



1 See Die Jura-Formationen, 1856-58, p. 357. ^ The Cotteswold Hills, p. 73. 



