Tlce Barrettia Beds of Javia ica. 505 



metamorphosed Cretaceous limestone outcrops near Moore Town 

 and up the Plantain Garden River in the far east of the island. 

 This, however, by no means precludes the possibility of their 

 occurrence at one or other of these localities. 



A large and extremely interesting series of Cretaceous fossils is 

 obtainable at all of the above-mentioned localities, both in the 

 limestones and in shales and mudstones which underlie certain of 

 the limestones and are mapped by Sawkins as part of his Trappean 

 Series. The study and investigation of these faunas will require a 

 very considerable amount of time and trouble, and as this paper is 

 intended to deal only with the Barrettia beds, their description 

 must be reserved till some future occasion. 



Since none of the other typical Cretaceous limestones is to be 

 seen above or below it at Green Island, it is impossible to ascertain 

 by direct observation in this locality where in the sequence the 

 Barrettia limestone should occur. 



The Rudist limestones of Jamaica appear to consist of discon- 

 tinuous lenticular reef-like intercalations among the great thickness 

 of fragmental sediments known as the Blue Mountain Series. The 

 general association of fossils seems to me to be rather different in each 

 of the typical Cretaceous Hmestone sections already referred to, some 

 fossils occurring in one locality and not in another. This makes the 

 attempt at any system of correlation or zonal sequence applicable 

 to the Cretaceous of the island as a whole seem a rather fruitless task. 

 Nevertheless, I feel convinced that in certain sections, such as that 

 at Jerusalem Mountain and that about Logie Green, a faunal 

 sequence of the Rudists and other moUusca can be traced. In this 

 connexion I may mention that the large Radiolites (Lapeirousia) 

 nicholasi Whitfield that accompanies Barrettia at Green Island is 

 common in the lowest Rudist limestones that are exposed in the 

 bed of the Rio Minho below Logie Green, where it occurs beneath 

 a fairly thick bed of " Trappean " conglomerate. It occurs also in 

 a road-cutting for some distance above the conglomerate bed, but 

 I saw no trace of it in the higher Rudist beds exposed at Logie Green, 

 and its position is at least two hundred feet below the top of the 

 Cretaceous beds exposed there. 



This fact goes to indicate the somewhat low horizon of the 

 Barrettia bed in the Jamaican Cretaceous limestone sequence. I am 

 inclined to suspect, however, that all the Cretaceous limestones in 

 Jamaica are of very late date, probably Maestrichtian. 



Description of the Beds. 

 The Barrettia limestone from which my collections were made 

 occurs on the Ilaughton JIall estate, near Green Island Harbour, in 

 Hanover Parish in Western Jamaica. The locality is apparently 

 the same as that referred to by Whitfield as Orange Cove. The name 

 Orange Bay is given on some maps to part of the coast which lies 

 some two miles south-west of the ridge of Barrettia limestone at 

 Haughton Hall. 



