hill: geology of Jamaica. 85 



against the southern margin of the Cobre formation, as seen imme- 

 diately back of the station in May Pen village ; it apparently occurs 

 along interior margins of the plain between Old Harbor and Clarendon 

 Park, known east and west of the Minho as Harris Savanna and Lime 

 Savanna respectively, and is thus apparently deposited along a former 

 coastal margin which once here attinged against the low back coast up- 

 lands through which the ]k)g Walk Canyon is cut, and previously shown 

 to be composed of the Cobre formation. 



Stratigraphically the May Pen beds occupy a position immediately 

 preceding that of the ancient alluvial deposits elsewhere described as 

 the Kingston. Fossils are numerous at May Pen, consisting entirely, so 

 far as we observed, of indeterminate casts of Mollusca, being free from 

 corals, especially of the reef building species. Further study of this 

 locality is very desirable. 



The Porus Formation. — From the crossing of the Cobre to beyond 

 Porus there are in the railway cuts many fine exposures of a forma- 

 tion resembling that at May Pen, consisting of loose, coarse textured 

 yellow clay marls accompanied by irregular lumps of limestone and 

 containing poor casts of fossils. Sufficient material was not obtained 

 from it to determine with exactness its stratigraphic position, although 

 it is, in general, to the coastward of the Bog Walk limestone, and ap- 

 parently above it. The fossils which we have seen from it have facies 

 more resembling those of the Bowden beds than of the later formations 

 presently to be described. 



There is also evidence that beds analogous to those of Bowden occur 

 on the south coast of Clarendon Parish at the foot of Round Mountain 

 near Bath, which, according to Sawkins,^ contain fossils of the same 

 genera as those found at Bowden (Port Morant). A coral from this 

 locality described by Duncan, and an Orbitulina by Jones, indicate fur- 

 ther identity of the horizons. Unfortunately, the writer has not visited 

 this locality. 



Of the beds described, only the Buff Bay and Bowden localities can 

 be correlated with positiveness at present. The inclined position of 

 the former shows that they participated in some of the later orogenic 

 movements of the island. 



The final key to the Jamaican sequence depends upon the determina- 

 tion of the upper relations of the Bowden and allied beds. That they 

 clearly overlie the greater mass of the white limestones I am most 

 positive, and are not at the base of all the white limestones, as asserted 



^ Jamaican Keports, p. 1G2. 



