THE BUILDING OK AN ISLAND. 7 I 



posed of a conglomerate formed of well water-worn pebbles of the older forma- 

 tion embedded in calcareous mud, and showing apparently an irregular stratifi- 

 cation dipping towards the north. The attention of the writer has been called 

 to a bed of similar conglomerate which crops out on a grassy knoll to the east 

 of the road as it goes over the top of Evening Hill, and which possibly may 

 be a continuation of the deposit at the Cay. This conglomerate of the Cay, 

 although so small a deposit, has in any case great interest, and especially so if 

 further examination should show that it is not a recent deposit, to be reckoned 

 as only a little earlier than our beach and reef limestones, but that it belongs 

 to the great formation covering the centre and south of the island.* 



It is, at all events, probable that the limestones of the Central Slope did 

 bend over to the northeast, and that the arch which would have revealed this 

 fact has been removed, perhaps in the first instance by the action of the sea on 

 the arch as it rose above the water, and later by the rains and consequent rills 

 which are still wearing back the hill front. Since the su])porting blue-beach 

 rocks must have shared in this arching, the comparatively low dip of these 

 rocks in some parts of Christiansted may possibly be due to it ; but on the 

 other hand it should be noticed that rocks of the same kind at Judith's Fancy 

 dip at about 45 degrees, so that fuller observation is needed before any clear 

 evidence in this direction can be adduced. 



In regard to the Central and Southwestern Plain, the interesting question 

 arises, how far has it been formed by the sea and how far by surface drainage ? 

 That the sea passed through it at an early period in the course of the elevation 

 seems to be likely; but the present form of its surface is certainly due to the 

 streams which during rainy seasons course over it. The fact that sea-shells are 

 found in various parts of it is no evidence, as some observers have supposed, 

 that the sea has recently been there, those shells having undoubtedly been left 

 by the Caribs on their visits to the forests or to their cultivated grounds. This 

 explains the presence of all the bivalve shells and some of the univalves, while 

 many of the univalves, found in nearly all parts of the island, have been carried 

 inland by the hermit crabs, whose cast-ofT homes they are. That the present 

 form of the plain is due to the streams which cross it we may see from the 

 shallow depressions which those streams have formed and into which the water 

 on either hand runs, bearing away the soil so as to leavvC slightly rounded sur- 

 faces between the watercourse and its next neighbours. 



The above remarks as to the action of the streams apply to all, or, at all 

 events, most of the plains in the island. The Parade Ground, east of Chris- 

 tiansted, though on only a small scale, furnishes an instructive example. If 

 in a dry time we enter the watercourse on the west side of the small triangular 



* From an inset chart of Christiansted Harbour on Captain Parsons' Chart of Santa Cruz it appears 

 that "The Cay," called also Protestant Cay, is about 270 yards long from north to south and about loo 

 yards wide. Its highest point is 34 feet above sea-!evel. At its northern end are the ruins of an old fort 

 (Fort Sophia Frederica). There are also residences for the Pilot and his staff, and a large cistern with 

 collecting apron. In excavating for the cistern the same conglomerate was taken out as is seen on the 

 surface. 



