14 THE GEOLOGY OF BERMUDA. 
All the rock in the interior of the islands, and all the rock which is | 
much elevated above the water level, is drift-rock. Indeed, substan- 
tially the whole mass of the rock visible in the islands is drift-rock. 
Probably along the greater part of the shore drift-rock comes down to 
the water’s edge, no other rock being visible. I was not able to exam- 
ine the whole of the coast, but I am confident that drift-rock comes 
down to the water’s edge along the north shore of the Main Island from 
Spanish Point to the Flats and beyond, along a part at least of the 
north shore of St. George’s, around a considerable part, if not the whole, 
of the circuit of Harrington Sound and Castle Harbor, around the head 
of Hamilton Harbor, and in many places even along the south shore of 
the Main Island—the region of the coast in which the beach-rock is 
best exhibited. North Rock, at least in its upper part, is formed of 
drift-rock, as is shown by the high dip of its lamination.* This char- 
acter of the rock is well shown in the beautiful photograph taken by 
Mr. J. R. Heyl, of Hamilton. The drift-rock is usually very soft, so that 
itis quarried out for building purposes by means of a peculiar long- 
handled chisel, in large blocks, which are readily sawn into pieces of 
such size and shape as may be wanted. Most of the houses in Bermuda 
are built of this exceedingly friable stone. Even the roofs are covered 
with the same material sawn into thin slabs. This stone, covered with 
a coat of whitewash, is sufficiently durable for ordinary buildings in the 
Bermudian climate. Exposed to the frosts of a New England winter, 
it would of course crumble very rapidly. Although the drift-rock is 
generally quite soft and friable, it is sometimes very firmly consolidated 
and of a suberystalline texture. This hard rock is quarried like any 
ancient limestone or marble, and has been used in the construction of 
the fortifications and other government works. The quarries at Payn- 
ter’s Vale and on Ireland Island are in such a hard drift-rock. The 
quarry of the Royal Engineers, near Elbow Bay, appears to be in beach- 
rock. It would be a curious question, what are the precise conditions 
which have determined the varying action of the rains on these accu- 
mulations of coral sand. While in some localities the sands have been 
merely washed away and dissolved, in others the grains have been, by 
the action of the same rains, cemented firmly together, until the rock 
has assumed a sub-stalagmitic texture, as at Paynter’s Vale. 
The usual softness of this drift-rock has made it a matter of small 
labor and expense to secure easy grades on most of the roads in the 
*Thomson, op. cit., Vol. I., p. 296. 
