318 Mr. Weaver's Geological Observations on 



and succeeded on the south-west by Mayhill, and the hills which, inclosing the 

 coal-tract of the Forest of Dean, pass on into Monmouthshire. But the more 

 immediate objects presented to the eye from this station, in the vale below, 

 are the narrow transverse valleys of the Avon and Falfield ; the former pro- 

 ceeding from the south-east, the latter from the south-west; and coinciding at 

 a short distance above the village of Stone, their united waters pursue a course 

 to the north-west, finding a vent in the Severn below the town of Berkeley. 

 The Falfield valley and the lower part of the Avon are bordered on the west 

 by the isolated table-lands and ridges of Eastwood and Whitecliff park ; while 

 the general course of the Avon is bounded on the east by the foot of the great 

 escarpment. 



In the view thus described, the eye takes in at a glance a succession of 

 geological formations, extending from syenitic granite up to oolite. 



On the other hand, the view from the southern brow, at Wood-end or Lay- 

 hill, bears a different aspect. Here we appear to stand on the northern \erge 

 of an elliptic coal-basin, the immediate prospect being confined on either side 

 by a continuous ridge, which, diverging to the south-east and south-west, in- 

 closes a plain : eastward of this ridge, the line of the oolite escarpment may 

 be seen extending uninterruptedly from north to south ; the horizon being 

 bounded in the latter direction by the Somersetshire ranges, which spread 

 from the great escarpment on the east to the Dundry and Broad-field Down 

 hills on the west, beyond which, in the extreme distance on the south, a part 

 of the Mendip chain appears. The re-entering angle formed by the northern 

 extremity of this basin, bears a close relation to the salient angle produced by 

 the conjunction of the valleys of the Avon and Falfield. 



§ 2. To ascertain the nature and connexion of the formations surveyed in 

 these two views, which, taken together, extend between sixty and seventy miles 

 from north to south, is the object proposed in the following pages : and as 

 Tortworth is a position nearly intermediate between the two extremes, and 

 comprehends within a narrow compass almost the whole of the formations that 

 will come under our notice, I shall consider its environs in such detail, as will 

 render unnecessary more than a general view of the north-west of Gloucester- 

 shire and north-west of Somersetshire ; since in the two latter tracts we com- 

 monly meet with only a continuation or repetition of the same formations as 

 occur in the Tortworth district. 



§ 3. The immediate environs of Tortworth, which I am about to describe 

 in detail, may be comprised in a triangle, the base of which passes from Old- 

 bury-on-Severn on the west, through Thornbury, Milbury-heath, and Wick- 

 war, to Hawksbury Upton on the east ; the two sides converging to a point at 



