174 Mr. De la Beche on the Geology of Jamaica. 



with the white limestone ; and at the Crawle itself I found casts of univalves 

 and bivalves in the limestone. 



We find the lower beds of this formation in the neighbourhood of Chapel- 

 ton, (Clarendon,) between which place and Pour Paths estate above-men- 

 tioned, the road exposes white marl, which is followed by whitish friable sand 

 mixed with gray, and a little red, marl : these beds dip to the N.N.E. at 

 about 45°. At Chapelton a whitish calcareous marl contains portions of yel- 

 lowish limestone full of broken fossil shells, some of which may be easily re- 

 cognised as of the Ostrea genus. Among these rocks I found specimens of 

 the large Cerithium formerly mentioned. Lower down the hill upon which 

 Chapelton stands, white limestones mixed with white marls and sands, some 

 of which are red, continue to where the whole formation seems to rest upon 

 porphyritic conglomerate. On the road to Savoy estate, a reddish and white 

 small-grained conglomerate, the pebbles in which are mostly porphyritic, 

 rests upon the other, and may either belong to the lower part of the white 

 limestone formation or the upper portion of the porphyritic conglomerate. 



The Barquadier road from Chapelton to the plains of Clarendon shows that 

 the limestones of that part of the Mocho Mountains dip at the first part of the 

 descent at an angle of 15° to the E. by S., and further down at about 20° to 

 the S.E. These limestones are continued to Lime Savannah, between which 

 place and Denbigh estate, in a woody part of the road not far from the former, 

 a small-grained conglomerate is interstratified with them, the pebbles of which 

 are principally quartzose. 



The white limestone formation is continued from the Mocho Mountains 

 across the Rio Minho, and forms the mountains on the left bank of the river, 

 which gradually fall into the low hills which separate the plains of Clarendon 

 and Vere from that of St. Dorothy's, and are continued to the sea in Old Har- 

 bour Bay. These low hills are also composed of the same formation, exhibit- 

 ing a mixture of compact white limestone, and white and red marls ; the 

 latter being frequently traversed in different directions by white calcareous 

 matter. In the rising behind Halse Hall House (Clarendon), which forms a 

 part of these low hills, white marl rests upon compact white limestone, among 

 which there is a breccia, composed of fragments of compact white limestone 

 cemented by a yellowish-brown arenaceous and calcareous substance. In the 

 white limestone behind Halse Hall House I found a Nautilus, Terebratulae, 

 and Nummulites, with numerous casts of the genera Area, Astarte, Cardita, 

 Cerithium, &c., and abundant casts of Astreae. The beds dip to the W.S.W. 

 at about 20°. 



Kemp's Hill, which rises out of the diluvial plain of Vere, is formed of 



