hill: geology of JAMAICA. Go 



by the Montpelier beds during the succeeding epoch. As shown in an- 

 other chapter, the age of these beds, although containing a remarkable 

 mixture of Cretaceous and Tertiary fossils, is undoubtedly Eocene, and 

 with the Richmond beds they constitute the Eocene system in Jamaica. 



The White Limestones. (Oceaxic and Coast Series.) 



Introductory Statement. — The transitional Cambridge beds grade up 

 into rocks of organic oceanic origin. These are the White Limestone 

 formation of the official Jamaican Reports. They have no genetic 

 relationship with the rocks of the Blue Mountain Series, and differ from 

 them in every physical and chemical aspect. 



The interpretation of the white limestones has been one of the 

 greatest problems of Jamaican geology. There have been so many di- 

 verse opinions concerning their age and sequence that it is almost impos- 

 sible to obtain from current literature any approximation of their true 

 relations and significance. The difficulties can be readily seen by any 

 one who reads the conflicting and apparently involved conclusions in the 

 Jamaican Reports. The fragmentary descriptions of their local occur- 

 rence are frequently well written, but through lack of correlation and 

 erroneous deduction they fail to clear up the sequence and age of the 

 beds. 



All the white limestones have been usually discussed by field ob- 

 servers under one general head, and treated and tabulated as a single 

 formation in the discussion by European geologists who wrote the Ap- 

 pendix, and one would infer that they are not stratigraphically subdi- 

 visible. There are numerous references, however, in the body of the 

 Jamaican Reports,^ from which it is obvious that some such distinctions 

 were at least observed, although the geologists failed to difi^erentiate, 

 name, or correlate them, as we shall endeavor to do in the following 

 pages. 



De la Beche ^ included all the rocks from our Cambrids^e beds to the 

 recent inclusive in his White Limestone, but recognized differences of 

 age therein and correctly referred the basal portion to the Eocene. 



Of the field geologists upon the Jamaican Survey, Sawkins held con- 

 cerning the White Limestone that " Uncertainty has prevailed respect- 

 ing its precise geological position, but paleontological evidence seems to 

 determine a Mid-Tertiary or Miocene period as the epoch of deposi- 



1 See Jamaican Reports, pp. 45, 53, 121, 214, 230, 231, 241, 250, 257. 

 » Mem. Trans. Geol. Soc. London, 1829, pp. 169-171. 

 VOL. xxxiv. 5 



