upper Formations of the New Red Sandstone System. 337 



To the south-east of Warwick, the red marls are so denuded, that there is 

 little hope of finding this band of sandstone clearly developed, though the 

 sandy character of the ground at Radford, about two miles from the lias escarp- 

 ment, seemed to us to indicate the range of the sandstone (see Section, 

 PI. XXVII., fig. 4.). The undulations and faults, near Warwick, by which 

 the younger beds are reproduced as outliers on the north-west, are, therefore, 

 very important for our present purpose. Having traced this peculiar sand- 

 stone through so wide an area, there was no difficulty in identifying it, when 

 discovered near Knowle and in the adjacent hills, between that place and War- 

 wick, as represented in Section, PI. XXVIL, fig. 4. Besides a precise mineral- 

 ogical resemblance with the sandstones of Burge-hill, Ripple, and Inkberrow, 

 the rock in Warwickshire contains the same peculiar little bivalve shell {Posi- 

 donomya minuta, PI.XXVIII., fig. 4.) which occurs at the southern extremity 

 of Worcestershire, and thus throughout a course of not less than forty miles, 

 we are enabled to mark the position of this thin band of sandstone, and to di- 

 stinguish it from other sandstones, which not only underlie it, but are sepa- 

 rated from it, by a great thickness of marl. 



Again, the exact geological position of this sandstone, which we consider 

 to be the equivalent of the Keuper sandstone of Suabia and Alsace, is 200 or 

 300 feet below the lowest beds of the lias, a position, which coincides well 

 with that of the principal mass of this sandstone in Wurtemberg, where one 

 of the authors has examined it. In Germany, however, the Keuper formation 

 contains several courses of sandstone and grit, but always subordinate to thick 

 masses of marl. In England, we have one well-defined band only, which, 

 occurring from 200 to 300 feet below the lias, is completely and distinctly 

 separated from the great red sandstone of the central counties, by a vast 

 thickness of red and green marls, which in certain tracts are saliferous. In- 

 dependently of natural sections, the great thickness of the red marls, or 

 the depth to which they extend beneath the Keuper sandstone, is established 

 by the shafts and borings made at the saltworks of Stoke Prior, near Droit- 

 wich, where the gypseous marls with masses of rock salt, were penetrated to a 

 depth of nearly 600 feet without an indication of ani/ bed of sandstone* . 



Combining these facts with the sections exposed in the escarpments of Ink- 

 berrow, Knowle, and other places, it appears evident, that the Keuper of Eng- 

 land (on the whole quite as largely developed as that of Germany) is, like t!ie 

 " Marnes Irisees" of Prance, a great marly formation, with one principal band 



* See Dr. Hastings's paper in the Analyst, vol. ii. p. 359. 



