18 Dr. Mac Culloch's Account of Guernsey, 



stone lying transversely and resembling masonry. I supposed It to 

 be a vein of columnar trap similar to that I noticed at Paregorois. 

 From Experquerie to Port des Moulins I could not examine the 

 coast. 



The descent into Port des Moulins is through a narrov^ pass of 

 wild rocks, and the scenery of it is of the most picturesque class. 

 Detached masses of rock surrounded by the sea, and relieved by the 

 broad cliffs which bound it, constitute its peculiar feature. The whole 

 of these rocks are of grauwacke schist and grauwacke. The strata are 

 nearly horizontal, and are occasionally intersected by veins of quartz, 

 as is common elsewhere. It is no where of a foliated fracture pro- 

 ducing roofing slate, but in many places breaks into pieces well adapted 

 for square masonry. In some places where it lies near to granite it 

 seems to undergo an alteration of texture, and to become more sili- 

 ceous. It is intersected in one or two places by wide and perpendicular 

 veins of the magnesian class of stones ; and where it is in contact 

 with those veins, it appears to pass into schistose talc, and indu- 

 rated steatite. 



The veins I have mentioned contain various kinds of steatite, 

 often so contaminated with iron and clay, and so indurated, as to be 

 difhcultly distinguished from the argillaceous tribe. 



Talc, talcaceous schist, and asbestus, are found in the same veins ; 

 and with the asbestus are slender veins of argentine spar. 



Lapis ollaris is also found there, as well as in the land lying above 

 the cliffs, from which I guess that this vein extends across the island. 

 It is applied by the natives to economical uses. 



A very large wall of a redish granite, the end of a vein from 

 which the schistose strata have been washed, stands far out on the 

 shore, forming a natural arch. Where the arch is formed, a softer 

 cross fissure seems to have existed from which the looser materials 



I 



