Yol. 55.] OK THE OCEAXIC DEPOSITS OF TRINIDAD. 183 



in the graveyard and from a roadside-trench, consisted of a buff- 

 coloured, very friable Globigerina-limestoue, overlain by a cream- 

 coloured Globigerina-msirl. The exposures on the road from 

 Princestown to Ste. Madeleine (mostly only in the roadside 

 drainage-trenches) were of ochreous-yellow, cream-coloured, and 

 light-grey Glohigerina-ioasiYh, 



At Ste. Madeleine Usine, at the time of my visit, a fine section 

 was exposed at the side of the factory below the Estate-house, 

 showing the lower beds of the foraminiferal deposits, while a few 

 yards off, and 30 feet lower on the opposite side of the works, was 

 a small exposure showing the clays of the jN'ariva Series. The lower 

 beds of the foraminiferal deposits do not consist, as in Barbados, of 

 a pure white or almost white chalk, but of a greyish-blue marl, 

 through which abundance of almost white spheres of Glohigerina 

 are clearly visible to the naked eye. These marls are overlain by 

 cream-coloured beds of Globigerina-msirl, weathering to a lighter 

 hue. 



Many exposures of the underlying clays of the Nariva Series 

 were examined on the various lines of railway running through the 

 Ste. Madeleine Estates ; these generally showed red, blue, and 

 mottled clays containing selenite in great quantity, and not 

 unfrequently in large crystals. These clays have, on many 

 occasions, unpleasantly reminded the Estate authorities of their 

 existence, for the coherence of their particles is not strong, and 

 frequent landslips have taken place on slopes and banks ^ so that 

 much expense has been incurred to guard against such slips in the 

 numerous cuttings of the Estate railways. 



After I had examined the district near Ste. Madeleine, I had the 

 advantage of the company of Mr. Guppy in my visit to the western 

 portion of the area. We visited the quarries and road-cuttings 

 in the upper parts of the marls on Philippine, Hermitage, and 

 Cedar Grove Estates, and examined the numerous exposures in the 

 roadside-trenches. In this part of the district the relationship of 

 the Oceanic Beds to the lower strata is far less apparent than in the 

 neighbourhood of Ste. Madeleine, but what I noticed served to 

 confirm my earlier observations. The road from San Eernando to 

 Hermitage gradually crosses the area of the Oceanic Beds at an 

 angle to the strike, and thus their sequence can be made out. 



Mr. Guppy, before our visit, told me that he had reason to believe 

 that the sequence from the Globigerina-heds to the radiolarian 

 marls was continuous. This we were able to confirm ; the 

 calcareous buff and cream-coloured Globigerina-m.a.Tls gradually 

 and almost imperceptibly change into more calcareous, heavy, white, 

 chalky beds, and from these into more and more siliceous beds, 

 becoming lighter in density and in colour until they assume 

 characters practically identical with those of the great mass of the 

 calcareo-siliceous radiolarian earths of Barbados. 



The Oceanic Beds appeared, as a rule, to dip at comparatively low 

 angles to the north, and to east and west of north, although in 



