Correspondence — Mr. J. Smiih — Prof. Rupert Jones. 93 



fragments of the frnstules of the diatom Fdhmodiscns, which is " quite 

 characteristic of some of the deepest tropical red clays and radiolaiian 

 oozes far from land," The 'argiline' beds appear to be formed from 

 the alteration of the lower (r/oft/^erma-marls. The following 

 correlation is proposed : — 



Barbados. Trinidad. 



Coral Eocks | Moruga Series ... Pleistocene mid Pliocene. 



Bissex Beds ) 



Oceanic Beds Naparima Marls ... Miocene. 



Scotland Beds I ^P?^'^ - ^^"^ Fernando Beds | Qligocene and Pliocene. 

 (Lower... Nariva Series ; 



The Oligocene and Eocene beds are of shallow-water origin, and 

 seem to be unconformably covered by the Naparima Marls. 



coI^:E^ESI=03:^^x:):H]^5^o:E. 



CETSTALS FEOM DECOMPOSED TEAP. 

 Sir, — Early in the year, in examining some refuse-heaps near 

 Dreghorn, Ayrshire, I found a few crystals which had been weathered 

 out from a decomposed trap. The altered rock is white, and on 

 exposure has fallen into dust, leaving the crystals isolated and 

 perfectly sharp. In some places the rock is particularly white, 

 and the crystals themselves have been reduced to powder. Much 

 of the trap is a hard solid rock, with large conspicuous aggregates 

 of enclosed crystals ; every variety from the solid rock to the altered 

 ' white horse ' (^ local name of white trap) can be obtained. I am 

 informed by Mr. L. J. Spencer, of the British Museum (Natural 

 History), that the isolated crystals are really pseudomorphs of 

 serpentine after augite. J. Smith. 



MONKREDDING, KiLWINNING. 



December 15, 1898. 



FOEAMINIFEEAL FLINT FEOM SOMALI. 



Sir, — The Eev. R. Ashington Bullen, E.G.S., lately lent me 

 some stone implements (labelled as having been collected by 

 Mr. Seton-Karr in Somali, Eastern Africa), for exhibition before the 

 Anthropological Institute, in illustration of my paper on large 

 African stone implements (see Journ. Anthrop. Institute, new sei'ies, 

 vol. i, 1898, p. 48). Some of these Somali implements are 

 composed of quartzite, rather ferruginous, gritty, and hard, though 

 the grains are only cemented at their peripheries, and not closely 

 compact ; others are of flint, coarse-grained hj the visible presence 

 of the minute organisms originally constituting the limestone of 

 which the flint is a more or less perfect pseudomorph, still to 

 a great degree calcareous. Many niicrozoa, chiefly internal casts 

 of Foraminifera, stand out on the roughlj'^ weathered surface, and 

 numerous sections of these organisms are seen in the fractured 

 stone. Some friends have examined the specimens with me, and 

 although at first I suspected small Nummulites to be present, we 



