124 Prof. Liveing, On the rocks of the Channel Islands. [Nov. 14. 



has thereby produced a fall of the superjacent rock leaving a 

 platform about 20 yards wide with a gentle slope seaward in the 

 plane of the bedding. 



The centre of elevation has been at the Port du Moulin above 

 mentioned : there the strata are upraised to the greatest height, 

 and are almost horizontal, and from that point they dip away in 

 all directions. The main line of dislocation appears to run from 

 this point across the island to the Creux harbour on the east side, 

 and has produced the ravine extending from the Port du Moulin 

 up the grounds of the Seigneurie, and that down which the road 

 runs to the Creux harbour. South of this line the strata dip 

 away towards the S.W. Their inclination at first is slight but 

 gradually increases to about 40° at the Coupee, as the isthmus 

 between Great and little Serk is called, and then diminishes again 

 to about 15° (measured by the eye only) at the southern end of 

 little Serk. To the north of the principal line of dislocation the 

 strata dip with a gradually increasing slope in a radial manner from 

 N.W. round to East. Northwards the schist dips under the syenite, 

 and the junction may be seen on the shore on the N.E. side near 

 the foot of the wall as you descend to the Epercherie landing 

 place, and on the N.W. side at a point nearly midway between 

 the Boutiques caves and the Autelets. On the west the schist 

 dips under the syenite near the extremity of Brecqhou. On the 

 south the junction may be seen on the shore of the Grande Greve 

 a little east of Point le Jeu, and a little north of the Moie on the 

 other side of Little Serk, both on the shore and in High Cliff 

 above. It is the great toughness and power of resistance of the 

 grey syenite which has preserved the projecting extremities of 

 the island at Little Serk, Brecqhou and Bee du Nez. 



The island is everywhere intersected by volcanic dykes mostly 

 vertical, and in many places also by veins of which one in Little 

 Serk is metalliferous, and was at one time worked for lead and 

 silver, but others are mostly mere cracks which have in places a 

 lining of quartz and have otherwise been filled up by debris from 

 the sides, and through the facilities they afford for the action of 

 the weather and the sea, have produced deep indentations of the 

 coast. The largest vein of this kind has thus given rise to the 

 Coupee, another to the Havre Gosselin. The volcanic dykes are 

 mostly greenstone, they are largest and most frequent on the N.W. 

 side, about the area of greatest elevation, and as their materials 

 are much more easily disintegrated than the tough hornblende 

 rock and syenite they have frequently been removed by the 

 action of the waves and weather, and left the deep chasms and 

 caves before alluded to. One of the most remarkable of the caves 

 runs right through the promontory called Moie des Moutons. The 

 dyke there is about 16 feet thick, and the lower part of it as high 



