DEPOSITS AND ELEVATION. 19 



These stones doubtless once lay at the feet of the now 

 overhanging cliffs amongst the breakers^ and in most cases 

 may be assumed to have fallen from a level somewhat 

 above that of the places where they now rest. 



All the holes^ that I have seen, occur in surfaces which 

 have obviously suffered some superficial waste. Hence 

 the smaller holes, which usually crowd the surface of a 

 burrowed stone off a recent beach, have generally disap- 

 peared, and the fossil holes which remain are the ends of 

 the larger perforations. 



The list following is purposely arranged along a rude 

 line of profile of the Head, from the north-east over the 

 Telegraph-hill to the precipices which overhang the isth- 

 mus on the south. 



1. At the stile above the archery-ground, in the foot- 

 way up to Gwydfyd farm, are two large slabs, each showing 

 several fine Pholas -holes. One is on the ground below ; the 

 other forms the coping of the westerly pillar of the stile. 

 Height 216 feet. 



2. In the cutting made to remove overlying clay above 

 the yellow clay-pit at Gwydfyd farm, a large cubical boulder 

 of limestone, measuring from 3 to 4 feet each way, and nine- 

 tenths buried in the superficial clay and humus, afforded a 

 very perfect group of three large burrows, with part of a 

 fourth. The largest hole is 4" deep, and i ^ in diameter at its 

 widest part. These holes were just visible above the sward. 

 It will interest naturalists to note that each was tenanted by 

 a large Helix aspersa. It is not quite safe to pronounce 

 upon the species of Pholas without the shells ; but, from 

 the shape of these three holes, which are singularly well 

 preserved, I am inclined in this case to suppose that they 

 were made by Pholas crispata, a species of well-ascertained 

 quaternary occurrence^. Height 350-360 feet. 



2 a. The same spot afforded another, smaller stone (2 feet 



* In the cases thus marked, specimens were exliibited. 



c2 



