Vol. 68.] ARDEN SAIS^DSTONE GEOTJP OF WARWICKSHIRE. 253 



108 square miles. The Keuper Marls occupy the whole of this 

 district, except where they are overlain in the south by the Rhaetic 

 and Lower Lias, and in the north, near Knowle, by an outlier of 

 the same formations. Geologically, the country forms part of the 

 southern portion of the broad syncline of New Eed Rocks that lies 

 between the South Staffordshire and the Warwickshire Coalfields. 

 Physically, it consists of a dissected plateau rising usually to 

 altitudes between 400 and 500 feet above O.D. in the north and 

 west, and sloping gently on the whole to the south-east and south, 

 the River Arrow at Wixford being only 110 feet above O.D. The 

 district is drained in the north by the Blythe and other tributaries 

 of the Tame, which falls into the Trent; and in the south by 

 the Alne and Arrow, which drain into the Warwickshire Avon 

 and so into the Bristol Channel. The topography of the watershed 

 between these two river-systems and the courses of the rivers are 

 interesting, but will not be discussed here. 



The district occupies the site of much of the ancient Forest of 

 Arden, but is now mainly given over to agriculture and is dotted 

 with old-world villages. The country is picturesque and well- 

 wooded, and affords a distinctly bolder type of scenery than does 

 the Keuper Marl country immediately to the north : a fact which 

 is no doubt attributable in some measure to the thinner mantle of 

 Drift, but is also partly due to the presence of a sandstone horizon 

 in the Marls of the area here described which gives rise to a number 

 of escarpments. Another set of ridges and low hills has been 

 produced by a hard zone lying at a higher horizon in the Marls than 

 the sandstone band ; while a third, and bolder, escarpment has been 

 formed at the junction of the Marls with the Rhsetic deposits. The 

 scarp-slopes, varying from 40 to 100 feet or more in height, are 

 frequently covered by woods and copses. Owing, as will be seen 

 later, to the low dips and undulations of the strata, they wind 

 about the country and so impart to it a particularly pleasant and 

 diversified aspect. The soil of the Marl country, except where the 

 sandstone zone crops out, is usually, and especially when freshly 

 ploughed, of a bright red colour, which adds warmth to the scenery, 

 particularly noticeable when intensified by the ruddy glow of the 

 setting sun. 



The marked change in colour observable, from the brilliant red 

 of the Marls to the pale-grey soil with sandstone fragments of the 

 sandstone zone, has been of the greatest assistance in tracing the 

 course of the sandstone horizon ; and, with the aid of the old marl- 

 pits with which the district is dotted, the stratigraphy of the area 

 can be usually worked out with close accuracy, except in places 

 where the drift deposits are thicker than usual. 



This sandstone is usually known as the Upper Keuper Sandstone ; 

 but, as it is evident from the writings of Prof. Hull (69),^ the late 

 Mr. Fox-Strangways,^ and others that two or more Upper Keuper 



1 The numerals in parentheses refer to the Bibliography, § XI, p. 276. 



2 ' The Geology of the Country between Atherstone & Oharnwood Forest' 

 (Expl. of Sheet 155) Mem. Geol. Surv. 1900, p. 36. 



t2 



