178 bulletin: museum of comparative zoology. 



There is no evidence that beds equivalent to the Cambridge are repre- 

 sented at all in the other islands of the main chain of the Windwaid 

 Islands, unless the Orbitoides and Nummulinee of Antigua, described 

 by Jones ^ from an unknown stratigraphic horizon, belong here. I am 

 disposed to consider them not later than the succeeding Montpelier 

 horizon. 



In Barbados and Trinidad it may be possible that the Cambridge 

 horizon is represented by a certain formation characterized by Nucula 

 schomburki, which is closely associated with the base of the equivalents 

 of the Montpelier beds next to be described. 



In San Domingo, as described by Gabb,^ the Yaqui shales, like the 

 Richmond shales of Jamaica, grade up into 400 feet of locally varying 

 beds, which, like the Cambridge, are " yellowish or brown or buff color," 

 and like them contain corals and Orbitoides. Many of the fossils noted by 

 Gabb, especially the Orbitoides and Nummulinse, are similar to those of 

 the upper part of the Cambridge beds of Jamaica, where they grade into 

 the Montpelier beds. Conrad ^ has previously asserted the Eocene char- 

 acter of the fossils of this formation, which Gabb erroneously included in 

 his Miocene. 



Tippenhauer* has more clearly described the Haitian equivalent of 

 the Cambridge than Gabb. His description of the beds leads me to be- 

 lieve that they are identical with the Cambridge beds of Jamaica in age, 

 composition, thickness, and fossils, thereby indicating a similar geologic 

 history during this epoch in the two islands. His descriptions are as 

 follows : — 



" The yellow limestone lies above the conglomerates and below the white 

 limestone. Its peculiar yellow ochreous color makes it readily recognizable. 

 Bright yellow marls and blue gray clay also occur in this formation. The 

 boundary line between the white and yellow limestone is very indistinct, ex- 

 cept that the white limestone is poor in fossils, while the yellow is exceedingly 

 fossiliferous. It is very rich in Foraminifera, Ostrea, and Echini. Instead of 

 the great compact masses of the higher-lying white limestone, the yellow lime- 

 stone shows series of distinctly stratified thin beds. For the most part these 

 strata consist of yellow, sandy, or clayey marl. In some places the limestone 

 is compact and crystalline. In such cases it forms a fine marble ; in others 

 it is impure and verges toward sandstone. The total thickness of this for- 



1 The Geologist, London, January, 18G4, pp. 102-106. 

 '^ Op. n't., p. 94 et seg. 



8 Smithsonian Miscellaneous Collection No. 200, p. 37, and Proc. Phila. Acad. 

 Nat. Sci., 1852, p. 108. 

 •1 Op. cit., pp. 85-87. 



