21A Mil. JUKES-BROWNE AND PROP. HARRISON 



of the Crane Hotel the rock becomes very hard in places, and great 

 difficulty was met with iu sinking a well through it. Under the 

 cliffs freshwater springs are seen, which discharge large volumes of 

 water with some force. The surface of the cliffs is hard, and is 

 in places coated with the mammillary form of aragonite. A recent 

 cutting on the surface of the cliff has, however, shown that, as 

 described elsewhere, this surface-hardening of the rock does noi 

 extend very far inwards. 



The mass of the rock generally consists of the broken fragments 

 of corals, nuUipores, moUusca, foraminifera, and echiuodermata, 

 the relative abundance of the fragments referable to each of these 

 classes being generally in the order stated, although occasionally 

 beds occur which consist chiefly of nullipores or of foraminifera 

 without any recognizable coral-debris. 



Where (as is usual) the rock consists mainly of coral-fragments, 

 himps and broken branches of Porites and other corals are scattered 

 through it, and occasionally large blocks of Heliastrcea, Siderastrcea, 

 and other massive reef-corals occur in the position of growth, but 

 the number of coral-fragments above 3 inches long is seldom large 

 enough to make up half the mass of the rock. Sir H. Schomburgk 

 has figured some of the large blocks of astraeiform corals which are 

 occasionally exposed, and which are sometimes 3 or 4 feet high. 



Recognizable shells of MoUusca are not always present ; but at 

 the lower levels, and especially where the rock is loose and earthy, 

 they are often abundant and well preserved. At the higher levels 

 the shells have been dissolved, and only casts remain. 



The followiug are notes of exposures seen between Ceres near 

 Bridgetown, and Castle Grant on the central ridge of the island. 

 Ceres is about 70 feet above the sea, and stands on soft marly rock 

 which has a hard crust for 10 or 12 inches below the soil. In this 

 material shells are common, especially univalves of the genera 

 Natica, Bulla, and Centhimn, and bivalves referable to Area, Lu- 

 cina, and Tellina. The large Stromhus gigas is not uncommon, 

 and is found up to levels of at least 400 feet, while casts probably 

 of the same species occur at much higher levels. 



Between Ceres and Grasettes the slope which rises from 70 to lUO 

 feet is in many places bare of soil, and the weathered limestone has 

 a dirty grey hue, which gives it a curiously antiquated aspect. 

 Broken and weathered lumps of coral are exposed here and there at 

 the surface, all of them partially calcified, so that the general 

 appearance of the rock and its contents is not unlike the more 

 coralliferous parts of our Carboniferous Limestone. It is, "however, 

 by no means hard, having been quarried in several places for 

 building-stone, and then the yellowish-white tint of tlie freshly-cut 

 rock recalls our Jurassic rather than our PalaDozoic limestones. 



At Spooner's Hill, above Kew, on the road to Warrens, the rock 

 is loose and soft, having the usual structure, but with an occasional 

 layer of still looser coral-sand. This continues to about the height 

 of 90 feet above the sea, when the road cuts through a much harder 

 rock, the matrix being far more compact, the coral-lumps mori- 



