SALIFEROUS MARLS AND SANDSTONE. 



29 



1. Saliferous Marls and Sandstone. 



Foreign Synonyms. — "Keuper" of the Germans, "Marnes irisees " of the French. 

 Qi. of coloured section, Plate 29. fig. 1. See also h of woodcut 1. p. 14. c. of woodcuts 

 3 and 4. pp. 22 and 26, and b. of woodcut 5. p. 28.) 



The whole of the New Red System, as seen in the narrow tract near Newnham and 

 Flaxley, in Gloucestershire, is exhibited only in the form of red and green marls, which, 

 on the east, pass upwards into Lias, and on the west repose unconformably upon the 

 Old Red Sandstone and Silurian Rocks. At Tibberton, five miles west of Gloucester, 

 they include courses of hardish sandy marlstone, of a light green colour, the upper- 

 most of which is nearly as white as chalk, and sometimes of a slightly brecciated 

 structure. No hard stone occurs in this formation between Gloucester and Newent. 

 As, however, we proceed northwards, the Burg Hill quarries, situated near the village 

 of Stainton, afford an exception, and contain a sandy marlstone of lightish green and flesh 

 colours, in some beds almost a grass-green, passing into calcareous, slightly micaceous 

 grit. From the neighbourhood of Gloucester to the north of Upton, the Severn flows 

 through soft Red Marl, exhibiting on its banks (as at the Mythe, north of Tewkesbury, 

 and near Upton) vertical sections of red and green beds, with spots of each colour- 

 Here the marls are of great thickness, and extend westward, almost to the foot of the 

 Malvern Hills, from which they are separated by only thin zones of sandstone and occasional 

 conglomerates. The junction line of the upper beds with the Lias, ranging from Glou- 

 cester to the north-east of Worcester, has been already described. The western boundary 

 of the formation in Worcestershire cannot be very accurately defined, in consequence of 

 the gravel which obscures so much of this low country; but, in general terms, it maybe 

 stated that the marls reach within a short distance of the Malvern and Abberley Hills. 

 Subordinate to these marls, and not far removed from their junction with the Lias, are 

 beds of whitish sandstone, which form thin courses at Combe Hill, west of Cheltenham ; 

 and at Bushley, west of Tewkesbury. At Longden they are thicker, and at Ripple on 

 the left bank of the Severn four miles north of Tewkesbury, they swell out to twenty 

 and thirty feet. This rock doubtless represents one of the sandstones subordinate to 

 red and green marls which occur at Coburg, Stuttgard, and other parts of Germany, and 

 at Luneville in France; constituting the "Keuper" formation of foreign geologists'. 



1 To convey to my readers some notion of the nature and succession of the strata comprehended by the 

 Germans under the term " Keuper," I herewith annex a section of that formation at Stuttgard, made by Pro- 

 fessor Sedgwick and myself in 1828. From this and subsequent observations of my own, particularly in the 

 neighbourhood of Nurnberg, Coburg, and Gottingen (1829), I came to the conclusion that the German forma- 

 tion, as established by Humboldt and Hoffmann, for the purpose of distinguishing the red marls and sandstone 

 which rest upon the Muschelkalk, from those which occur beneath that limestone was the true equivalent of the 

 upper division of our English New Red Sandstone. I afterwards stated this opinion to the Geological Society, 



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