MOOEE — ABNORMAL SECO>"DART DEPOSITS. 



521 



8. Section at Brocastle. — On taking the road from Bridgend to 

 Cowbridge, numerous small Liassic sections are passed, in which Ain- 

 monites Sauzianus and other remains show that they represent the 

 higher members of the Bridgend section. After passing these quar- 

 ries and finding them all of the same general character, it was my 

 intention to proceed direct to Cowbridge ; but when midway, at 

 Brocastle, at the mouth of the Liassic inlet previously indicated, I 

 observed a limekiln some way up an arable field, on the right of the 

 roadway, and thinking the beds there might occupy a difi'erent horizon 

 I determined to give them an examination. Instead of a Liassic, it 

 proved to be a Carboniferous Limestone quarry, very full of encri- 

 nital and other remains of that age. A shallow cartway from the 

 field led into the northern face of the limestone. On leaving the 

 quarry, a thin deposit of conglomerate, resting on the limestone 

 immediately under the soil, attracted my attention, and was at once 

 seen to contain many beautifal corals and univalves, the age of which 

 could not then be recognized, but the Liassic character of which sub- 

 sequent examinations revealed. 



The section itself, given below, rendered at first but little assist- 

 ance in determining the age of the deposit. 



Fig. 6. — Section at Brocastle. 



a. Lower Lias. 



b. Conglomerate. 



c. Carboniferous Limestone. 



d. Lead-vein. 



d. A vertical fissure about 3 feet wide, formerly sunk about 50 feet in depth 

 for lead-ore. 



c. Eastern face of nearly horizontal Carboniferous Limestone, 12 feet thick, 

 leading in from the field to the quarry. 



b. Capping of Liassic conglomerate, accommodating itself to the edges of 

 the beds or to the surface of the Carboniferous Limestone when it formed the 

 base of the Liassic sea, averaging about 1 foot in thickness. 



a. Dense irregularly bedded Pentacrinital Liassic limestones with Rhyncho- 

 nella variabilis and corals, exposed for about 5 feet in height, but the thickness 

 of which is unknown, dipping slightly towards the centre of the Bx'idgend basin, 

 abutting against and gradually passing into the conglomerate. 



The very interesting fossiliferous deposit, No. 3, is in part com- 

 posed of angular blocks of Carboniferous Limestone, united by a very 

 dense variegated yellow, grey, or bluish Liassic limestone, and en- 

 closing also small pockets of Carboniferous Limestone sand, with 

 organic remains of that age, and into which colonies of Liassic Litho- 

 domi have penetrated. 



The bivalves of this deposit are usually so surrounded by its dense 

 matrix as to be difficult of extraction, and for this reason are as yet 

 but imperfectly represented in my collection. Some of the corals, 



