16 Mr. De la Beche on the Geology of Southern Pembrokeshire. 



ing from West Angle on the west, to Giltar and Lidstip Points on the east. It 

 lies in a trough or hollow formed by the dipping beneath it on either side of the 

 old red sandstone belonging to the Pembroke and Orielton divisions of sand- 

 stone. 



At West Angle there is an excellent section of the western end of this 

 trough, the beds resting conformably on the sandstone on either side, but 

 being contorted in the intermediate parts. (See PI. II. fig. 3.) The lime- 

 stone near Pwlychrocan is almost concealed by diluvium, containing rolled 

 pieces of the sandstone and limestone : it may be seen, however, at Greenhill 

 Farm, Upper Hentland Farm, and Eastlington Mill*. The character of this 

 band of limestone, as occupying a trough, is well displayed at Pembroke, 

 which lies in the middle of the hollow. At a small cliff to the west of Bentlas, 

 near Pembroke, the limestone dips to the north at an angle of ?0°, and at the 

 opposite side of the river, near East Pennar Farm, to the south at 80°. At 

 Hodgeston the beds are highly inclined, with a drift from west-north-west to 

 east-south-east. At Rock Farm, to the north of Jamestown, they dip to the 

 south at about 60°. In Manorbeer Bay and at Lidstip Point they are vertical, 

 with a drift from west-by-north to east-by-south. At the cove north of Old 

 Castle Head the vertical limestone abuts against the sandstone. In the lane 

 between Lidstip and Penally, near Druselton Farm, the limestone dips to the 

 south at 45°, and in the cliff behind the same farm to the same point of the 

 compass at 80°. 



St. Margaret's Island and the northern half of Caldy Island form the con- 

 tinuation of the limestone of the Pembroke trough. The strata there are 

 nearly vertical. 



To the north and south of the limestone of this trough, between the lime- 

 stone and the old red sandstone, wherever a good section is afforded, the 

 slaty beds of the lower limestone-shale are to be discovered. This is particu- 

 larly observable in West Angle Cliffs, at Grove and East Pennar Farms, and 

 at a small cove between Shrinkle Farm and Old Castle Head. Wherever the 

 shale is exposed to the sea, small coves are formed, as the shale yields more 

 readily to the action of the waves than the limestone- and sandstone-rocks 

 which bound it. The bottom of the deep indenture in the west side of Caldy 

 Island is formed in the continuation of the slaty beds of the cove to the north 

 of Old Castle Head ; and the same beds traverse the island from west to east. 

 They become less calcareous as they approach the old red sandstone. 



The remains of Encrini, Corals, Productae, and Euomphali are found in the 

 limestone of the Pembroke band. 



* The stone of the latter place is very apt to fuse into scoriae in the kiln. 



