184 



MESSES. J. B. ITAKRISON & A. J. JFEES-BKOWNE 



[May 



places, as at Cedar Grove and at Hermitage, the rocks dip at some- 

 what high angles, this being apparently caused by local faulting. 



The Oceanic Series of Waparima differs greatly, in the relative 

 development of its various members, from the typical series seen in 

 Barbados. In the latter island the series is ushered in by white 

 and greyish-white chalks, containing from 60 to over 80 per cent, 

 of calcium carbonate, which in the course of about 20 to 30 feet 

 pass through calcareo-siliceous beds into the siliceo-calcareous and 

 siliceous earths forming the main mass of the deposit with a 

 thickness of about 170 feet. I was not able to obtain any exact 

 measurements in Trinidad, but the Globigerina-nmr] appeared to be 

 approximately from 120 to ]40 feet thick in the localities where I 

 examined it ; while the radiolarian beds did not appear to exceed 

 40 or 50 feet in thickness. I did not observe any layers of volcanic 

 ashes like those so frequently interbedded throughout the Barbados 

 series, but Dr. Gregory has described a pumiceous earth from this 

 district which was sent to him by Mr. Guppy.^ 



Samples were collected from the beds examined, and were analysed 

 by the methods described in the paper on the geology of Barbados." 

 For comparison, the analyses of samples of the middle and higher 

 beds, which were tabulated in the above-mentioned paper, are 

 reproduced in the following table. The analyses recently made 

 are numbered 1 to 3, those previously made being Nos. 4 to 6 : — 



/^Loss on ignition 



I Calcium carbonate ... 

 A ■{ Calcium phosphate ... 



I Magnesium carbonate 



l^ Colloid silica 



/^Iron peroxide and 

 alumina 



I Manganese peroxide. . 

 B-{ Lime 



j Magnesia ... 



I Clay 



l^ Alkalies and loss 



C. Quartz 



]). Calcium sulphate 



Globigeri7ia-hed8. 



Passage-beds. 



Eadiolarian beds. 



1. 



4-97 



2. 



3. 



4. 



5. 



6. 



G-21 



317 



2-38 



4-62 



2-11 



33-23 



35-81 



48^83 



40-50 



29-46 



31-82 



•SO 



•02 



•28 



... 



trace 



trace 



114 





ri9 









5-73 



7-22 



10-29 



19-66 



41-15 



41-56 



•71 



•28 



r23 



5-64 



3-31 



4^10 



•32 



trace 



trace 



•32 



•44 



•82 





133 





1-22 



Ml 



1^50 



•05 



•56 



•04 



2-34 



•41 



118 



49-44 



38-93 



29^13 



26-38 



15-36 



15-16 



trace 



•20 



•29 



trace 



trace 



trace 



3-37 



8-67 



539 



1-38 



4^()5 



1^47 



•78 



•77 



•16 



•18 



•09 



•28 



100^04 



10000 



100-00 



100^00 



10000 



100-00 



[The bracket A includes the organic constituents, the bracket B the argil- 

 laceous and earthy constituents, and D is regarded as an adherent salt.] 



Quart. Journ. Geol. Soc. vol. xlviii (1892) p. 539. 

 Ibid. p. 182. 



