196 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
two islands which throw the greatest light upon the age of the 
vulcanism of the Caribbees. 
In Antigua the older massive volcanic rocks constitute a high moun- 
tainous region on the south side of the island, while to the northward 
for miles these are overlapped by a vast thickness of stratified tuffs, 
evidently the ejecta from the vents of which the massives aro the 
remnantal stocks. "This material must be thousands of feet in thick- 
ness. It contains beds of thin lime deposits of marine origin, including 
a bed of older massive consolidated crystalline limestone less than ten 
feet in thickness, and an old coral reef. Towards the north end of the 
island the tuffs aro overlain by conglomerates grading up into chalk 
marls with fossil Mollusca of possible Miocene age. In the tuffs there 
are also beds of chert with vast quantities of fossil wood, land shells, and 
silicified reef building corals (but no reef rock), which also extend into 
the marls. Finally there is a small area of elevated reef rock. Of 
these stratified formations none in my opinion, except of the Orbitoidal 
crystalline limestone, can be of older age than Pliocene or late Miocene. 
The latter may possibly be Vicksburg—an opinion based upon the 
occurrence therein of Orbitoides and Nummulinw, described by T. 
Rupert Jones. Upon the erroneous correlation of others he referred 
these beds to the Miocene, but they are older in age than the Bowden 
beds of Jamaica “Miocene” with which they have been confused by 
many writers. These facts show that the volcanic tuffs of Antigua 
were being formed before the Vicksburg epoch, and that the Caribbean 
vulcanism was then active. 
In Guadeloupe we have somewhat similar evidence concerning the 
evolution of the volcanic range and the mass of sedimentarios. This 
island is composed of two parts of about equal area, separated by 2 
shallow ereek, Riviere Saléo. The most western of these islets (Basse 
Terre) is a typical volcanic pile of the main Caribbee chain, and 18 
thoroughly mountainous. The most eastern area, Grande Terre, is 82 
elevated cut plain, composed of sedimentary formations of Pleistocen® 
age underlain by a platform of volcanic tuffs, etc., derived from the 
volcanic débris of Basse Terre. Still to the eastward of Grande Terre 
is the small island of Desirade, composed entirely of organic material, 
which, with several other islets, stands above a shallow submerged plat- 
form extending out from the south east end of Grande Terre and Ba 
Terre. To the southward of Grande Terre is the island of Marie 
Galante. This island is of the same topographic and geologic type as 
Grande Terre. 
