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 Windward 
Islands, unless the Orbitoides and Nummulin® 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 Nummulina, are similar to those of 
the upper part of the Cambridge beds of Jamaica, where they grade into 
the Montpelier beds. Conrad è 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 ag 
composition, thickness, and fossils, thereby indicating a similar geologic 
history during this epoch in the two islands. His descriptions are 99 
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, €% 
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 erystalline. In such cases it forms a fine marble ; in other? 
it is impure and verges toward sandstone. The total thickness of this for 
1 'The Geologist, London, January, 1864, pp. 102-100. 
Op. cit., p. 94 et seg. 
Smithsonian Miscellaneous Collection No. 200, p. 37, and Proc. Phila. Acad. 
Nat. Sci., 1852, p. 198. 
Op. cit., pp. 85-87. 
os 
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