186 FALKLAND ISLANDS. [CHAP. ix. 



man carries four or five pair of the bolas; these he throws one after 

 the other at as many cattle, which, when once entangled, are left 

 for some days, till they become a little exhausted by hunger and 

 struggling. They are then let free and driven towards a small 

 herd of tame animals, which have been brought to the spot on 

 purpose. From their previous treatment, being too much terrified 

 to leave the herd, they are easily driven, if their strength last out, 

 to the settlement. 



The weather continued so very bad that we determined to make 

 a push, and try to reach the vessel before night. From, the 

 quantity of rain which had fallen, the surface of the whole country 

 was swampy. I suppose my horse fell at least a dozen times, and 

 sometimes the whole six horses were floundering in the mud 

 together. All the little streams are bordered by soft peat, which 

 makes it very difficult for the horses to leap them without falling. 

 To complete our discomforts we were obliged to cross the head of 

 a creek of the sea, in which the water was as high as our horses' 

 backs; and the little waves, owing to the violence of the wind, 

 broke over us, and made us very wet and cold. Even the iron- 

 framed Gauchos professed themselves glad when they reached the 

 settlement, after our little excursion. 



The geological structure of these islands is in most respects 

 simple. The lower country consists of clay-slate and sandstone, 

 containing fossils, very closely related to, but not identical with, 

 those found in the Silurian formations of Europe ; the hills are 

 formed of white granular quartz rock. The strata of the latter 

 are frequently arched with perfect symmetry, and the appearance 

 of some of the masses is in consequence most singular. Pernety * 

 has devoted several pages to the description of a Hill of Kuins, the 

 successive strata of which he has justly compared to the seats of an 

 amphitheatre. The quartz rock must have been quite pasty when 

 it underwent such remarkable flexures without being shattered 

 into fragments. As the quartz insensibly passes into the sand- 

 stone, it seems probable that the former owes its origin to the 

 sandstone having been heated to such a degree that it became 

 viscid, and upon cooling crystallized. While in the soft state it 

 must have been pushed up through the overlying beds. 



In many parts of the island the bottoms of the valleys are 

 * Pernety, Voyage aux Isles Malouiuc?, p. 52G. 



