A. Sfrahan — Lower Keiqjer Sandstone. 401 



In the earlier works on the Trias of Cheshire, the base of the 

 Keuper was placed at this horizon, namely, at the base of the Water- 

 stones, the Keuper Basement Beds being classed with the Bunter 

 (see papers by Mr. Ormerod and others). This classification was 

 changed in 1 852 and the following years by Prof. Hull, for reasons 

 which he gives in full in his Memoir on the Triassic and Permian 

 Eocks of the Midland Counties, p. 9. These reasons, stated briefly, 

 are the absence of any sign of a break in the sequence from the 

 Lower Keuper Sandstone up into the Red Marls, but an apparent 

 unconformity between the Lower Keuper Sandstone and the under- 

 lying beds. 



It seems then that if the separation between the Lower Keuper 

 Sandstone and the Waterstones is as well mai'ked in other districts 

 as in those which have been at present re-examined, the former 

 of these reasons for dissociating the Lower Keuper Sandstone 

 from the Bunter will be done away with, for in those localities 

 which have been described above, though there is no unconform- 

 ability, there is no passage from this rock up into the overlying 

 Waterstones. 



With regard to the second reason, namely, the break at the base 

 of the Lower Keuper Sandstone, it is necessary to avoid over- 

 estimating the value of the evidence brought forward in its favour. 



It was believed that the Bunter had been upheaved and suffered 

 great denudation before the deposition of the Keuper and that the 

 discordance in the dips produced by these pre-Keuper movements 

 was actually visible in a section at Ormskirk (Triassic Memoir, 

 p. 87). But on examining the section, I came to the conclusion 

 that there was no discordance in the dips of the two rocks, and that 

 certain beds in the Bunter which rise up to and end off against the 

 base of the Keuper, were only a portion of the current-bedding of 

 the former rock, and did not represent its true dip. More striking 

 instances of the cutting off of current-bedding planes may be seen 

 at the junction of the Waterstones and Frodsham Beds (figured in 

 the Memoirs on Prescot and Chester). 



Further evidence of the denudation of the Bunter is sought in the 

 fact that the Lower Keuper rests on beds of different colour in 

 Cheshire and Lancashire. For instance, on p. 85 of the Memoir, it 

 is stated that in the southern part of Liverpool "the Keuper 

 Conglomerate is found resting on red sandstone, which, as may be 

 seen at the Red Noses on the sea-coast at New Brighton, underlies 

 a considerable series of yellow sandstone of the Upper Bunter ; the 

 whole of which has in this instance been denuded away before the 

 Keujjer period," and again in the Geology of Wigau, p. 32, "the 

 yellow beds are between 200 and 300 feet in thickness, and therefore 

 when we find in any special locality the Lower Keuper Sandstone 

 resting upon the red beds, we are driven to conclude that the whole 

 of this 200 or 300 feet of strata have been denuded away in that 

 place." But I have previously shown how rapidly the Upper 

 Mottled Sandstone and other subdivisions of the Trias vary in colour. 

 This evidence of denudation, resting on the identification of horizons 



DECADE II. — VOL. YIII. — NO. IX. 26 



