The Cretaceous and Tertiary Question in Jamaica. 429 



or Eiclimond beds ^ or beds mapped as Trappean intervenes 

 between the Yellow and the Rudist Limestones, and which are absent 

 from this section. 



The White or Cockpit Limestone rests in one place along the line 

 on rotten yellow Carolia marls, and in another place, about a mile 

 further to the south, on weathered Cretaceous shales. I was con- 

 vinced that these masses of White Limestone are partly or in some 

 cases completely detached from the main escarpment which 

 surrounds the outcrop of the older and softer beds in an amphitheatre- 

 like manner, and have to a greater or less extent travelled by slipping 

 down the slope of the valley of the Great River. The older beds in 

 this section are much rotted and decomposed where they are seen 

 immediately under the White Limestone. The position of the White 

 Limestone also in this section is anomalous, since in some other 

 imdisturbed sections in Jamaica the Yellow Limestone seems to 

 grade up with perfect conformity into the White Limestone. 



The Nature of the White Limestones. 



As regards the great White or Cockpit Limestone of Jamaica, 

 the Montpellier, Moneague, and Cobre formation of Hill, which 

 attams a thickness of over 2,000 feet, and covers about three-quarters 

 of the island, it does not appear to me to be advisable to apply the 

 terni oceanic to this formation. Its character does not seem to be of 

 nearly such an oceanic nature as, for instance, does that of the 

 English Chalk. Massive compound corals, together with pisolite- 

 like bodies, casts of Cerithium, Cypraea and other molluscs, are 

 common in it, forms which are by no means of oceanic but rather of 

 shallow-water character. Unfortunately, fossils are very poorly 

 preserved and are nearly all merely casts. It may be remarked that 

 the supposed Oligocene age of this formation is not as yet founded 

 on any very definite palaeontological evidence. There seems to me 

 to be absolutely no evidence to connect it in any way with the 

 oceanic marls of Barbados. Parts of it may be of late Eocene, 

 Oligocene, or early Miocene age. The deepest-water portion of it 

 seems to be that which lies at the base, namely, the foraminiferal 

 flinty chalks called the Montpellier beds, which are locally developed 

 but very well seen near Montpellier, but in these beds also casts of 

 bivalves and other mollusca are abundant in places. American 

 geologists seem generally agreed in correlating the Montpellier Lime- 

 stone with the Vicksburg beds. 



I am strongly inclined to think that the White Limestone originally 

 covered the whole area of what is now Jamaica, as there is no trace 



^ Dr. Matley suggested to me, what I had once or twice vaguely susjjected, 

 his opinion that the Richmond beds may possibly replace the Yellow Lime- 

 stone in some parts, though in some areas, such as Glasgow in the extreme 

 north-west, both the Richmond beds and the Yellow Limestone occur. It 

 is to be hoped that further research both in the field and also on the fossils may 

 assist in determining this question. 



