192 THE GEOLOGICAL AGE OF CENTRAL AND WEST CORNTVALL. 



Nos. 4 and 5. These occur on the N. side of the river, 

 opposite No. 3, one on each side of the old " Bar House," about 

 a furlong apart, and near the inlet known as Navas Creek. On 

 one of these veins an adit has been driven in a N.N.E. direction 

 for a considerable distance, some deluded speculators having 

 been led to regard it as a mineral lode, and induced to 

 " adventure " on it in search of mineral wealth. It is probable 

 that the continuation of these veins might be discovered by 

 careful search in the neighbourhood of Caerwinion or Mawnan 

 Smith, but we have failed to find them on several occasions 

 when passing through the district. 



No. 6. The veins numbered from 1 to 5 are none of them 

 marked on any geological map hitherto published. No. 6, which 

 occurs in the cliffs beneath Mawnan Church was briefly described 

 by Sir H. Dela Beche in his classical " report," already referred 

 to. He gives a little figure of one of its modes of occurrence at 

 that point, which is here reproduced, together with his remarks 

 thereon. " In one j)lace," he says, " in the ledge of rocks near 



Fig. 2. — Ula-oJiiaji Cliffs, f}-o)n Dela Beche. 



Mawnan Church, dry at low tide, we see the singular intermix- 

 ture of trap and slate represented beneath. The dark shaded 

 part representing the trap, which has aj^parently been injected 

 in an irregular manner amid the laminae of the slate, forming 

 a continuous mass beneath, it merely having so happened that 

 the plane of the ledge cuts the junction of the two rocks so as to 

 produce this ai:)pearance. The trap probably forms a portion of 

 a dyke, which in the adjoining cliffs cuts partly among the beds 

 and partly cuts through them, in one place including a large 

 piece of the rock which it traverses.'' * 



A private communication with which one of us has been 

 favoured by the Eev. Wm. Eogers, the rector of the parish — 

 informs us that the trap rock appears again at surface in the 

 northern part of the churchyard, and that blocks of it were used 

 by the builders of the oldest portions of the church. Northwards 

 from the churchyard, this particular vein has not been traced, 

 * Bep. on Cornwall, Devon, &c., pp. 93, 94. 



