134 
Bulletin 35 
282 
PAPER No. 17. 
SECO.VD NOTE ON THE M A REEL A MANJAK MINE 
Dept. Agr. Trinidad, Bull. Agr. Information, Jan-Apr., 
1909- PP- 5 >- 54 - 
Page 51 
Having been favoured by James Wilson, E.squire, of Messrs. 
Goodwille and Wilson, with samples of the rocks found in the 
Marbela Manjak mine, I was enabled to present a short prelimi- 
nary note on the subject published in the Proceedings of the Vic- 
toria Institute, 1904, and in the Geological Magazine, London, 
1904, page 276. 
The receipt of additional samples of >the rocks, the last of 
which came through L. J. Bernstein, Esquire, induces me to 
modit}* my opinion on some points, and I therefore contribute a 
.second note on the subject. 
Down to a depth of about 40 or lift}" feet the material ob- 
tained in sinking the mine is mostly of a heterogeneous character, 
showing extensive disintegration and disturbance due partly to 
pluvial and weathering agencies and partly to human interfer- 
ence. Below that we have indurated cla3's and sandstones con- 
taining g\-psum, and it is in the.se and the subjacent strata that 
the manjak occurs in veins and seams. These continue down to 
about 160 feet, and were apparenth* laid down in an area where 
tide-water and flood-water were alternately admitted. These de- 
])Osits were extremeh’ fine grained and the clastic matter in them 
is mostly ver}' fine sand with a large proportion of argillaceeus 
matter, showing that its origin was at a considerable distance. 
But below this the fluviomarine character gives place to a decid- 
edlv' marine one, though the proportion of calcareous matter is 
still much less than in the tj'pical Naparima rocks. These rocks 
show the gradual shoaling of the water b}’ matter brought down 
b\’ the rivers from the neighboring continent. The foraminiferal 
fauna which in the lower beds is of an entirelj' deep sea character 
becomes graduallj' driven out, and onl}’ those .species remain 
