410 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 23, 



tougher, and more marly part of the Upper Boulder- clay. The stone 

 facing or " hulking " of the sloping shore from the New Pier to the 

 Gynn, conceals this clay on the coast ; but in the gully close to the 

 Gynn Inn a fine coast-section of it commences. It reaches a thick- 

 ness of at least 30 feet, and may be distinctly seen overlying the 

 middle sand and gravel for a distance of about two miles in a north- 

 erly direction, and irregularly attenuating until it is lost under blown 

 sand. In its upper part it is generally of a dull red colour and 

 somewhat incoherent ; in its lower part it is compact, and often of a 

 grey or blue colour. Generally speaking, though not always, stones are 

 rather sparingly distributed through it, and they are seldom large. 

 A kind of grey siliceous sandstone, occasionally with quartz veins, 

 is perhaps the most prevalent ; but greenish grey porphyry is very 

 common, and granite not unfrequent. A large boulder may here and 

 there be seen. The upper part of this deposit is used as a brick- 

 clay and the lower as a marl*. It is apparently devoid of stratifi- 

 cation, though, I believe, the action of spades in brick-pits and of 

 rain on sea-cliffs is capable of effacing aU traces of bedding in either 

 of the Boulder-clays (see Lower Boulder-clay between Bardsea and 

 Baycliff). The Eev. Mr. Thornber informed me that he found a 

 lump of haematitic iron-ore from the Eurness district in this clay. 



h. Middle Sand and Gravel. — Beneath the Upper Boulder-clay a 

 very fine section of sand and gravel may be seeu exposed in the cliff 

 north of Blackpool. It would appear to thin out in a southerly di- 

 rection before reaching Blackpool, or under some part of the town, 

 as no trace of it can be detected on the coast south of the New Pier, 

 where the lower clay comes nearly to the surface, and is directly 

 overlain by Scotch slutch or (a little further inland) by the upper 

 clay. I have not seen it exposed further south than the Gynn 

 gully. It cannot be cut off by a fault in the gully, as the lower 

 clay underneath preserves a nearly uniform level all along the shore. 

 It probably wedges out between the two clays a short distance to the 

 south of the Gynn. In the Gynn gully, about 30 feet in thick- 

 ness of the sand may be seen capped with the upper clay. Here the 

 edges of the laminae have to a certain depth been cut off by denuda- 

 tion on the landward side. To the north of the Gynn the deposit 

 of sand and gravel is well known; and many sea-shells ( Cardium, Tel- 

 Una, &c.) have been found in it by Mr. Binney, Mr. Darbishire, and 

 others. It consists of successive beds of fine and coarse sand dis- 

 playing many varieties of obhque lamination and false bedding, 

 alternating with layers of well-rounded pebbles likewise more or less 

 false-bedded. The sand comes nearly to the surface immediately to 

 the north of Uncle Tom's Cabin, but again becomes covered with 

 the upper clay. Northwards, nearly a mile beyond Uncle Tom's 

 Cabin, the middle drift consists almost entirely of arenaceous beds 

 (capped with clay) which dip towards the north at a small angle, 

 the surface of the ground above nearly conforming to the dip, until 

 in the direction of RossaU these beds are lost under blown sand. 



* The existence of marl-pits in this part of the country may almost be regarded 

 as an indication of Upper Boulder-clay. 



