14 Christinas Island — Valleys. 



The western flank of the island differs considerably from the 

 north and east, the upper cliffs being represented apparently by 

 gentle slopes, and even the first inland clitf, except towards North- 

 West Point (Fig. 5) and Egeria Point, is less clearly defined than 

 elsewhere. Another peculiar feature is the occurrence of several 

 narrow dales or gorges running towards the coast in a direction 

 a little south of west. Some of these cut down to the sea-level, 

 others open out on the shore terrace (as above defined). In 

 several cases their floor is formed by volcanic rock, and in the 

 wet season they are traversed by a small stream which descends to 

 the sea in a succession of falls and rapids. At the time of my visit 

 (October) there was no water in any of these valleys except one 

 towards the north (see Map, Hugh's Dale); but the rounded steps 

 and boulders, both of limestone and basalt, show that a considerable 

 volume of water must pass during the rains. The surface of the 

 basalt is often covered with a thick coat of lime deposited from 

 the water. Some of the falls are of considerable size ; one in 

 Sidney's Dale, formed by the edge of a bed of basalt, is 40 feet 

 high by about 30 broad. 



The cliffs shutting in the valley are sometimes 50 to 60 feet 

 high. They are generally much more developed on one side than 

 the other ; and on the northern side there may be merely a steep 

 slope, while on the southern there is a vertical cliff. The mode 

 of formation of these valleys will be considered in the geological 

 section, but it may be here mentioned that although water has 

 no doubt helped to deepen them — and in the case of those which 

 reach the sea, has cut through the shore terrace and sea cliff — 

 they do not appear to owe their origin to this agency. 



From time to time a good deal of slipping and faulting has 

 taken place round the flanks of the island, and in some localities 

 has been so extensive as to materially modify the arrangement of 

 the inland clifi's and terraces. 



Perhaps the most extensive of the slips that have taken place is 

 on the east coast a little south of North-East Point and beneath 

 the eastern sIojdcs of Phosphate Hill. Here for some distance the 

 first and second inland cliffs, or the slopes representing them, are 

 interrupted by a precipice, the upper edge of which is from five 

 to six hundred feet above the sea-level ; the lower third or so is 

 covered with a talus of immense blocks of limestone. This cliff' 

 seems to be the result of the slipping down of an outer portion 

 of the island, extending inland nearly as far as the cliff spoken of 

 above as the third inland cliff. This movement must have taken 

 place before the elevation which gave rise to the present shore 

 terrace and sea cliff, since these are continuous with tho^^e to the 

 north and south, and can be seen to consist, here as elsewhere, of 

 a raised fringing reef, which has here grown out upon the foot of 

 the talus slope above mentioned, and sometimes has included f'illen 

 blocks within itself. 



JNorth of the high cliff just noticed the first inland cliff is 



