88 bulletin: museum of compakative zoology. 



east coast and closely resemble them in composition and texture. This 

 formation is apparently the oldest of the Coastal Series of this vicinity 

 occurring by later and unconformable deposition in a pre-eroded plain 

 back of Montego Bay, which in former times was evidently a bight into 

 the present back coast hills. 



It is our opinion that the position of the Manchioneal beds along the 

 south coast west of Yallahs Mountain is largely occupied by the older 

 part of the Kingston formation next to be described. 



Nowhere have we seen the Manchioneal beds occur at a higher alti- 

 tude than 300 feet, if that high. Barrett ^ mentions them as occur- 

 ring at a height of 140 feet at Blue Hole, and 300 feet near Port 

 Antonio.^ 



From the low position of the Manchioneal formation adjacent to the 

 coast and unconformably against the older and more disturbed white 

 limestones, it is evident that it was a marginal fringing deposit. Its 

 stratigraphic position above the Bowden formation and below the un- 

 doubted elevated reef rock to be described later, as well as the paleou- 

 tologic evidence of its pteropods and Brachiopoda, indicate the Pliocene 

 age of this formation. The contained corals, here poorly developed and 

 occurring in increasing proportions in the succeeding beds, mark the 

 first definite appearance of the marine reef building species in the 

 Jamaican sequence. 



The Kingston Formation} — The extensive gravel covered plains of 

 the south side of the island of which that known as the Liguanea is a 

 type, have been fully described in the chapter " Geography and Physi- 

 ography," Part I. of this Report. 



These plains are composed of formations consisting mostly if not 

 entirely of aggradational material derived from tlie adjacent uplands 

 of the mountains and plateau. This material varies in composition, 

 being mostly detritus of the Blue Mountain Series to the east of 



1 Jamaican Keports, p. G6. From his submarine explorations of the adjacent 

 seas he estimates that similar deposits are now forming at 150 fathoms (900 feet), 

 and that the sea bottom has been elevated this amount plus the present altitude of 

 the formations (300 feet), or a total of 1,200 feet since they were made. 



2 Ibid., p. 82. 



' The material of the Kingston and allied formations are well described under 

 tlie general liead of " Alluvium," in the portions of the Jamaican Reports dealing 

 with the parishes of St. Andrew, St. Dorothy, Vere (now a district of Clarendon 

 Parish), and St. Catherine. See Jamaican Reports, pages 101, 102, 142, 149, 161, 

 and 180. Thev are also discussed under the head of " Plains " on page 100 of 

 the same Report. 



