hill: geology of jamaicv. 63 



Peet. 



Hard compact yellow limestone, very crystalline ; thickness about 10 



Soft yellowish shaly limestone 5 



Soft shaly yellowish limestone, showing peculiar strained concre- 

 tionary nodules in one part of the bed 2^ 



Yellowish limestone, hard and coarse 2 



Yellow marl 



It is an interesting fact that Brown considered the yellow limestone 

 beds of Christiana, from which Mr. F. C. Nichols later collected sev- 

 eral of the Rudistes recently described by Professor Whitfield,^ to be of 

 Eocene age. This strongly suggests that future study of the locality 

 may reveal a mixture of Cretaceous and Eocene genera like that occur- 

 ring at Catadupa. 



The Cambridge beds, with their characteristic fossils, especially the 

 oyster and large Cerithium, outcrop at many places in St. Ann, notably 

 at Cave Valley, Boroughbridge, Yankee River, Pedro estate, and in the 

 beds of Negro and St. Ann Rivers. They have also been noted in Tre- 

 lawney at several places, and beds of Orbitoidal limestone with other 

 fossils are well exposed near Freeman's. The outcrops of the Cambridge 

 in Westmoreland and Hanover parishes are all in the same general dis- 

 trict as those of Catadupa and Cambridge in St. James, — the three 

 parishes meeting in this vicinity. The thickness is from 40 to 300 

 feet. 



The identity of this formation is involved in Jamaican literature. In 

 places it is clearly defined and in others its identity is entirely lost. 

 In De la Beche's chapter on the " White Limestone " of Jamaica,^ 

 many descriptions of these beds and their fauna can be recognized. It 

 is also the "Nodular Limestone " of Barrett's posthumous section pub- 

 lished by Woodward,® and mentioned in our introductory chapter. 



In the Jamaican Reports it is the "Yellow Limestone" of Sawkins's 

 general section on page 24, and' of the western parishes of St. Elizabeth, 

 St. James, Hanover, and Westmoreland, as described by Brown, who 

 considered the formation to be Eocene. In the descriptions of the re- 

 maining parishes it has been so confused under many names with other 

 beds of different age and position that its identification is somewhat diffi- 

 cult, although by careful study of the reports uncorrelated descriptions 



1 BulL Am. Mus. Nat. Hist., New York, 1897, Vol. IX. pp. 185-196. 



2 Jamaican Reports, pp. 100-182. 



3 The Geological Magazine of 18G4. 



