276 E. J. L. Guppy—The Marbela Manjah Mine. 



A further consequence of this discovery must be the removal of 

 that very great series of compact conglomeratic Grauwacke-beds so 

 common on the right bank of the Rhine and elsewhere — in Devon- 

 shire, for example ' — from the Culm to the Upper Carboniferous, thus 

 reverting to the view held some years ago by H. von Dechen and 

 E. Ludwig. This follows from the fact of their lying near 

 Battenberg still higher than the Konigsberg strata, shown to be the 

 equivalents of the Vise horizon, i.e. of the Upper Carboniferous 

 Limestone, and that the expression ' Culm ' can only be employed to 

 express equivalence with the Lower Carboniferous. We must look 

 upon the Giauwackes, containing the well-known flora (Lepido- 

 dendron, Avclmocalamites, etc.), as an equivalent of the Millstone 

 Grit of England and the Flotzleere Sandstein of Westphalia. 



It remains only to be added that the originals of the fossils 

 mentioned in this sketch are preserved in the museum of the 

 Geological Institute of the Imperial University at Marburg. 



VIII. — Note on the Marbela Manjak Mine, Trinidad. 

 By E. J. Lechmere Guppy. 



I HAVE been favoured by James Wilson, Esq., with samples of 

 material from the Marbela Manjak Mine. They are — 



No. 1. Clay from No. 1 Gallery, 75 feet deep. 

 No. 2. „ No. 2 „ 127 



No. 3. „ foot of shaft, 150 



No. 4. Sand-rock. 



There is no essential difference between Nos. 1, 2, and 3, and No. 4 

 only differs in being harder, not liable to disintegration by water, 

 and in containing more arenaceous and less argillaceous matter than 

 the other samples. Calcareous matter in all the samples is from 

 15 to 20 per cent., and consists almost entirely of shells of 

 Foraminifera. There is a considerable amount of sulphur, chiefly 

 as pyrites, greatest perhaps in No. 3, and fragments of Manjak'^ 

 occur in No. 1. 



In appearance there is much resemblance between this material 

 and that of the Naparima oceanic beds, though the latter is generally 

 of a lighter colour. But on examination a very considerable 

 difference is found to exist between the two formations. Both are 

 extremely fine-grained substances, indicating deposition in some 

 depth of water. But the proportion of argillaceous and arenaceous 

 matter in the Marbela samples is very much greater than in the 

 oceanic beds. This betokens in the former case the greater nearness 

 of land and the influence of rivers. In the Marbela samples the 

 sandy matter mostly occurs in the form of lumps or irregular small 



1 TJssher : "The Culm Measure Types of Great Britain " ; London, 1901. 



^ Manjak is a substance originally found in Barbados. It is geologically coal, 

 but chemically a form of bitumen. It is described in Schombm-gk's " History of 

 Barbados," pp. 551, 569; and (as coal) in Proc. Sci. Assoc. Trinidad, 1877, p. HO 

 (see Guppy on Coal, etc., Proc. Vict. lust. Trinidad, p. 507). 



