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ON THE GEOLOGY OF BARBADOS. 215 



three of them are foraminiferal muds, and one is a foraminiferal 

 limestone. 



We did not recognize the existence of such intermediate deposits 

 when -we were in Barbados, and we do not think that they any- 

 where attain a thickness of more than 10 or 12 feet. Prom the 

 facts now known to us we believe that they rest on different 

 parts of the Oceanic Series, and probably in some places on the 

 Scotland Beds. 



We consider them to have been formed by the action of currents 

 gently washing over the surface of the earlier deposits, when a 

 general upheaval of the area had brought this surface to within a 

 depth of 400 fathoms. They may have been formed in any depth 

 between this and 50 fathoms, but they afford no evidence that 

 any part of the bank was within the limit of coral-growth. The 

 following descriptions are condensed from reports by Mr. W. Hill 

 and Miss Raisin. 



(1) Foraminiferal Muds. 



Bath, 130 feet. — A yellowish clay. This clay appears to consist 

 of fine felspathic material and minute crystals of calcite ; the 

 whole is in a state of very fine subdivision. A good many Globi- 

 gerincB are to be seen in the thin section. 



Bath, 132 feet. — Prom a boring on the Bath estate, S.W. of the 

 Mill. A greenish clay. This is practically a foraminiferal deposit 

 in which Glohigerina is the predominating form. There is, how- 

 ever, a large amount of inorganic material. Miss E-aisin says of 

 this specimen : " The calcite is in very minute crystals ; felspathic 

 material is largely present, but a few distinct fragments of larger 

 felspar (and also what is probably quartz) can be recognized." 



CoWs Cave, 60 ft. below the gully-floor. — A greenish earthy 

 marl similar to the last, but with fewer foraminifera. Of the 

 inorganic material Miss E-aisin remarks : " The rather larger 

 mineral chips are more numerous, and can be recognized as broken 

 crystals and fragments of clear felspar." 



Several examples of foraminiferal volcanic muds from the west 

 coast of Java and from the Solomon Islands were kindly supplied by 

 Dr. H. B. Guppy and compared with the Barbados deposits. None 

 agree in character with the Oceanic foraminiferal or radiolarian 

 earths. 



But one of them from ''4 miles inland on the W. coast of Java" 

 compares to a certain extent with the foraminiferal mud of Cole's 

 Cave. Both consist largely of inorganic material, which for the most 

 part is probably felspathic, and in both there are many Glohigei-ino'. 

 But in the Java specimen the inorganic matter is coarser ; there 

 occur pumice and volcanic glass, neither of which can be recognized 

 in the greenish earth of Cole's Cave ; nor is there in either of these 

 specimens a preponderance of the minut6 calcite-crystals which is a 

 feature in the two other foraminiferal muds of Barbados. It is 

 singular that in two deposits which have much in common there 



Q. J. G. S. No. 190. Q 



