180 MESSES. J. B. HAEEISON & A. J. JUKES-BROWNE [Ma}^ 1 899, 



He gives some account of Naparima Hill, which is close to 

 San Fernando, but says very little of the Naparima district, where 

 the radiolarian marls are found.^ He mentions some exposures of 

 them in South Naparima, but none which showed their junction 

 with the foraminiferal beds. In his tabular arrangement, however 

 {op. cit. p. 538), he places the radiolarian beds at the top, as part of 

 the Miocene, and connects the Glohic/erina-mavls with the Eocene 

 beds of San JFernando, while the argiline of Naparima Hill is put 

 still lower, as the top of the Cretaceous. Thus these three sets of 

 beds are regarded as belonging to three separate formations, widely 

 diiferent in age. 



Mr. Guppy has contributed largely to our knowledge of the rocks 

 of Trinidad, and has furnished us with valuable lists of their fossil 

 contents, but from the foregoing resume it will be seen that his 

 writings leave both the nomenclature and the succession of the 

 Trinidad Tertiaries in a very uncertain state. 



Pirst, with regard to the nomenclature. When, in 1866, 

 Mr. Guppy described the San Fernando section, he was quite 

 justified in separating the beds in which he then found fossils from 

 the rest of the Naparima Marls, and in giving them a separate 

 name. Again, when at a later date he found a diff'erent set of 

 fossils in certain other beds, he very properly proposed to give them 

 also a special name, the No do s aria-beds. In 1892, however, 

 he seems to have assumed that these two sets of beds were parts 

 of one continuous series, and. that they formed part of the Naparima 

 Series of the Geological Surveyors. Hence he abandoned his own 

 names, and reverted to that given by Wall & Sawkins. 



The question now, however, is not whether those authors meant 

 to include certain beds at San Fernando in their Naparima Marls, 

 but whether these particular beds really belong to the same for- 

 mation as the typical marls of Naparima. If they do not, and if 

 there is an unconformity between the two sets of deposits, then it 

 is obvious that the name jN"aparima Marls must be restricted 

 to the Glohigerina~mdiY\% and radiolarian beds alone, and that the 

 San Fernando Beds must retain their name as part of a much older 

 formation. 



Next, with regard to the general succession, Mr. Guppy considers 

 the Nariva Series to be newer than any part of the Naparima Beds ; 

 but the dark clays which occur in the ISTaparima district were 

 mapped as Nariva Beds by Wall &l Sawkins, and were regarded 

 by them as underlying the ' infusorial earths.' 



Three definite issues are thus raised — (1) Are the Nariva Beds 

 above or below the ISTaparima Marls ? (2) Do Ghbirjerina-maAs 

 occur in the ISTaparima district ; and, if so, are they connected with 

 the radiolarian marls, or are they part of a separate formation ? 

 (3) What is the relation between the San Fernando Beds and the 

 other groups ? 



Prof. Harrison's observations were made in May 1895, but he 



1 Two samples of radiolarian earths are, however, described in an appendix 

 by Dr. J. W, Gregory, from specimens sent to him by Mr. Guppy, Quart. 

 Journ. Geol. Soc. vol. xlviii (1892) pp. 538-539. 



