472 Notices of Memoirs — R.J.L. Giq)py — Naparima, Trinidad. 



4. Cyrena semistriata, Desh. 

 I had attached the manuscript name of craigiana to this shell, but 

 a closer comparison of the numerous specimens contained in a slab pre- 

 sented by Mr. Craig to the Victoria Museum caused me to feel doubtful 

 whether it ought to be accounted distinct from the C. semistriata of 

 the European Tertiaries (Pictet, Paleontologie, pi. Ixxvi, fig. 10 ; and 

 Forbes, Isle of Wight, pi. iii, fig. 2). It is akin to C. solida, Phil., of 

 Central American rivers. 



5. There is also a very remarkable bivalve whose fragmentary 

 condition prevents determination. 



The collection indicates fluviatile or estuarine conditions, and has 

 resemblances to the Tertiaiy deposits of the Amazons valley, whose 

 fauna has been described by Conrad (Amer. Journ. Conch., 1870) and 

 H. Woodward (Ann. Mag. Nat. Hist., 1871). I am of opinion that 

 a Pliocene age is denoted. 



Note. — In addition to the papers referred to by H. Woodward in the 

 place above cited, there is a paper by Etheridge in the Quarterly ' 

 journal of the Geological Society of London, 1879, vol. xxxv, 

 pp. 82-8, on fossils collected by Barington Brown in the Amazons 

 valley. 



XV. — On the Cement-producing Materials of N'apaeima, Trinidad.* 

 By R. J. Lechmere Guppt. 



WHEN I retired from office under Government at the beginning of 

 1891, I undertook an examination of the rocks of Naparima in 

 Trinidad. These formations had occupied my attention at intervals 

 ever since 1859, when I first studied them. The discovery of the 

 wonderful series of Foraminifera, of which I had previously gained 

 only a glimpse in 1872, was the first reward of that examination; 

 but as a collateral result I found that we had here a very extensive 

 series of deposits apparently suitable as material for the manufacture 

 of cement. I inquired of the Public Works Department if this 

 information would be of any use to them, more especially as the beds 

 passed through and were developed on Government lands. The reply 

 I got was that all the cement wanted could be furnished by the Crown 

 Agents for the Colonies and there was no need of any local supply. 



The results of my examination of the Naparima rocks were 

 embodied in a paper read to the Geological Societj^ of London and 

 published in their Journal, November, 1892, p. 519.- In that paper 

 I casually mentioned the occurrence of cement materials in these rocks 

 in these words (p. 530) : "I think it highly probable that in some 

 of the marls we have a material suitable for the manufacture of 

 cement." It was not until this paper was before the Geological Society 

 that I was aware that Messrs. Harrison and Jukes-Browne had been 

 working at the geology of Barbados and had read a paper thereon 

 before the Society, These gentlemen were good enough to forward to 



* Bulletin Botanical Department, Trinidad, July, 1908, Article No. 1006. 



* See Geol. Mag., 1892, p. 331, and a further paper in Geol. Mac, 1900, 

 pp. 322-5. 



