chap. iv. Turk's Cap and Prosperous Bays. 9 1 



glimmering scales, or of minute acicular crystals, of 

 feldspar, placed close by the side of each other, and 

 abounding with minute black specks, apparently of 

 hornblende. The basaltic strata of Prosperous Hill 

 project only a little above the level of the gently-sloping, 

 feldspathic streams, which wind round and abut against 

 their upturned edges. The inclination of the basaltic 

 strata seems to be too great, to have been caused by 

 their having flowed down a slope, and they must have 

 been tilted into their present position before the erup- 

 tion of the feldspathic streams. 



Basaltic ring. — Proceeding round the island, the 

 lavas of the upper series, southward of Prosperous Hill, 

 overhang the sea in lofty precipices. Further on, the 

 headland, called Great Stony-top, is composed, as I 

 believe, of basalt ; as is Long Range Point, on the 

 inland side of which, the coloured beds abut. On the 

 southern side of the island, we see the basaltic strata of 

 the South Barn, dipping obliquely seaward at a con- 

 siderable angle ; this headland, also, stands a little 

 above the level of the more modern, feldspathic lavas. 

 Further on, a large space of coast, on each side of Sandy 

 Bay, has been much denuded, and there seems to be 

 left only the basal wreck of the great, central crater. 

 The basaltic strata reappear, with their seaward dip, at 

 the foot of the hill called Man-and -Horse ; and thence 

 they are continued along the whole north-western coast 

 to Sugar-Loaf Hill, situated near to the Flagstaff; and 

 they everywhere have the same seaward inclination, 

 and rest, in some parts at least, on the lavas of the basal 

 series. We thus see that the circumference of the 

 island is formed by a much-broken ring, or rather a 

 horse-shoe, of basalt, open to the south, and interrupted 

 on the eastern side by many wide breaches. The 

 breadth of this marginal fringe on the north-western 



