<i Geology of St. Croix. 73 
ble; especially at a little distance below the surface. It is often 
dug up for the purpose of deepening the soil, and left to decom- 
pose upon the surface. T'he lower beds, which rarely appear on 
the surface, are seen to good advantage along the southern coast, 
and consist principally of coral and shells converted into a ae 
mass of nearly pure lime. ‘The name coral crag, which f 
applied to them, well describes their general appearance. . 
superficial beds, which are very imperfectly stratified, and have 
the appearance’of a chemical deposit, vary in thickness on the 
coast front two to ten feet. The coral crag isnot peculiar to St. 
Croix. Isaw extensive beds of it in Barbadoes and Jamaica, 
where it often rises to the surface of the ground. 
‘The whole calcareous group, which I have now described, ob- 
viously belongs to the tertiary formation. 'The first and most 
recent Yass may be classed with the formation of Guadaloupe, 
rr ink do not extend back beyond the newer Pliocene 
do not speak with entire confidence, because nearly 
h itis often difficult to decipher the genera and species. 
Fossil coral, unaccompanied by marine shells, also occurs in 
many places; sometimes beautifully colored, and incrusted with 
calcareous depositions. Whatever may be the age of this forma- 
tion, it is no doubt more recent than the indurated clay ; for, in 
addition to other facts already suggested, we find imbedded in it 
great quantities of angular fragments and even large masses of, 
rocks from that group. This circumstance may be explained on 
the supposition that the island has been elevated at two different 
periods ; indications of which, if I mistake not, are found at 
several places, and especially at Jolly Hill, a distance of about a 
mile from the-west coast, and near a hundred feet above its level. 
They consist of a calcareous deposit by the side of the road, near 
the mill, upon the uplifted strata of the indurated clay. resembling 
those which I have already described; and stratified banks of 
gravel contiguous to the garden, in which: marine and lagoon 
— are es ieenceiies imbedded. On tte lower grounds be- 
< 
* The two best localities for + shells are a quarry near Dr. Stedman’s at the west 
end of the island, and one at the east end, from which building stone was obtained 
for the new prison. 
Vou. XXXV.—No. 1. 10 
