Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/28

 16 nodules rudely approaching to ocular agates. These are accompanied by veins of mica and felspar in various states of decomposition, apparently from the failure of the mica, and by veins of chlorite containing here and there pyrites, together with talc and quartz, and calcaceous schistus, and a mixture of greenish steatite, felspar, and quartz. The rocks here also are of trap formation, and the beach is covered with jaspideous pebbles as at Havre Gosselin.

Such is Grande Havre, and the number of the soft veins here existing may serve to account for the great waste the land has undergone. The Coupée is becoming daily lower to the eye.

The southern point of the island is formed of a sienite, but there is no opportunity of tracing its connexion with the trap of the western shore; for, from the Coupée to l'Etat there is no access, unless under circumstances of weather which rarely occur.

The Etat very much resembles in shape the Mewstone of Plymouth, and from its appearance and inclination is probably of the same formation as that I have been describing. The felspar of the sienite is invariably white, and not nearly so beautiful as that of Guernsey before mentioned. It is intersected by various trap veins, one of the most remarkable of which near Paregorois runs N and S, inclining about 3° to the W, and is about six feet in thickness. This vein consists of trap porphyry and amorphous trap; and besides these, regular hex angular blocks, the sides alternately large and small, are quarried out of it. I was unable to find in what position they lie, as the vein was only accessible at low water, but from what I observed in a similar vein at Experquerie, I am inclined to think that the columns lie across it. Their joints are flat. Some veins of a brick red felspar are also here to be observed, and in some places the sienite passes into greenstone; but as this part of the coast is almost inaccessible, it is difficult to say what varieties may exist in it. The