550 Aubrey Strahan — Rocks beneath the Coal-measures 



to be southerly, that is, towards the Silurian shales, close up to the 

 point where these shales reappear. This point is marked by slips 

 in both sides of the cutting, necessitating the covering up of the 

 side-drains. 



From Chilvers Coton northwards there is no section showing the 

 base of the Coal-measures for nearly four miles, but its position is 

 indicated by the rise of the ground, where the harder Silurian shales 

 with the intruded diorites rise to the surface. There can be little 

 doubt that the Coal-measures rest almost directly upon the highest 

 beds seen in the Midland Eailway cutting near Stockingford, for it is 

 known that the workable coal-seams crop out in the depression which 

 lies at the west end of the cutting. They are not exposed, but two 

 or three hundred yards south of the Accommodation Bridge there is 

 an old pit, now ploughed over, in which fragments of soft Carbon- 

 iferous sandstone occur, and which probably marks the position of 

 the boundary of these beds. On following the boundary northwards, 

 we find it marked by the outcrop of a seam of coal in the bed of 

 the stream west of Camp Hill, the hill itself consisting of the shale 

 with diorites, etc., seen in the western part of the railway cutting. 

 The coal-seams, which have been for the last two miles resting close 

 upon the Silurian shales, now begin to be separated from them by 

 beds which thicken steadily northwards. The nature of these beds 

 is first seen near Oldbury Hall. A pebbly sandstone dipping gently 

 to the west, and resting with a marked unconformity on the Silurian 

 shales, may be traced continuously from here to the Atherstone and 

 Birmingham high road. The rock is seen in the sides of a pond at 

 Oldbury (Farm) ; in the foundations of the farm west of Hopwood 

 Coal Wood ; in a sandpit near The Mawbournes ; and in some old 

 quarries 200 or 300 yards further west in the edge of the wood. 

 The rock is buff- coloured or white, and so soft as to be readily 

 broken down into sand by the use of a pick. It is associated with 

 some mottled red and white clays, which are exposed in the brook 

 near the south-west corner of Hopwood Coal Wood, and were found 

 in laying the pipes of the Atherstone Waterworks along the lane 

 which passes the sand-pit. The red tinge, however, is not confined 

 to the lowest beds of the Coal-measures, but may be seen in many 

 of the fireclays associated with the workable coal-seams. The sand- 

 stone is seen again in the north part of Monks Wood in an old pit 

 close to a small quarry in diorite and Silurian shale, and again in the 

 side of the bridle-path leading into the high road, but from this point 

 northwards the beds which underlie the coal-seams rapidly disappear, 

 until the seams come down, as at Stockingford, close on top of the 

 Silurian shales. 



The unconformity between the Coal-measures and the Lower 

 Silurian shales, which is generally masked on this side of the Coal- 

 field from the accidental parallelism between the bedding of the two 

 formations, is here very marked. The dip of the Coal-measures is 

 slight, ranging from 6° to 8°, while that of the Silurian shales ranges 

 from 20° to 40°. As a consequence of this the Coal-measures, where 

 they extend eastwards, at Mawbournes, overlap a great thickness of 



