HILL: GEOLOGY OF JAMAICA. 81 
mation, In this region the Cobre formation is very much honeycombed, 
and weathers into blood-red soils. At one place where laborers were 
blasting unusually large masses of the limestone, specimens from its in- 
terior were secured, which clearly showed the red iron blotches in the 
interstitial cavities. 
There are a number of isolated outliers of this formation standing in 
the midst of the Liguanea and other plains composed of later alluvium 
in the parishes of St. Catherine and Clarendon, as shown in Figure 26. 
Figure 20. Outlier of Limestone in Liguanea Plain, near Spanishtown. 
aa, Cobre Limestone, bb, Kingston Formation. 
These are of the type known in America as monadnocks, Two of these 
May be conveniently seen on the Kingston road a mile or two east of 
"Spanishtown.! These consist of the same limestone as that seen in the 
Bog Walk section (see Fig. 25). 
At the convict quarry back of Rock Fort, about four miles east of 
Kingston, where Long Mountain bluffs against the seacoast, a superb 
*Xposure of limestone has been made by quarrying. It is so lumpy 
that it is worked by the pick and used for road metal. Under the 
microscope it is composed of numerous undetermined species of Forami- 
difera, entirely different from those of the Montpelier and Cambridge 
eds. In the western group of parishes, forming the county of Corn- 
Wall, it may constitute the summit formation and pointed hills of the 
Cockpit country. This idea is suggested by the lithologic aspects of 
the rocks comprising these hills, and from outcrops in Manchester along 
the highlands bordering the Montego Bay Railway. Close research has 
Mot been made to determine this. A prominent feature of the Cobre 
formation is the blood-red residual subsoils which everywhere result 
Tom its surface decay. 
From the Bog Walk section it is evident that the Jobre formation 
ies stratigraphically above the supposed Moneague beds at Ewarton 
! Lennox (Jamaican Reports, pp. 140-151) described the formation of these hills 
der the name of the * Port Henderson Limestone," 
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