1878.] O38 [Crosby. 
low the limestone; hard sandstones,sometimes approaching quartzite, 
and occasionally decidedly ferruginous; conglomerates and thin beds 
and seams of calcareous matter. The phenomena of the quartz 
veins are even more characteristic of this series than of the first. 
The other accessory minerals are the same. It is noticeable that the 
veins of quartz rarely occur except in those rocks —argillite and 
mica slate — which, when subjected to lateral pressure as during the 
formation of folds and contortions of the strata, experience local 
partings of the layers in a direction parallel with the bedding, giving 
rise to lenticular cavities. The limestone, quartzite and massive 
sandstone are incapable of behaving in this manner, and such veins 
as exist in these rocks are usually transverse to the bedding. The 
amount of local contortion and faulting which all these Caribbean 
rocks have experienced, is very great. 
The first and third series have approximately the same apparent 
thickness, and both exceed the second or limestone belt. 
In the conglomerate that forms part of the series above the crystal- 
line limestone, I have observed pebbles that were almost certainly 
derived from the quartzites and mica slate of the first series; but 
beyond what this implies we have no evidence of a lack of conform- 
ability between the different terranes above described. Unconforma- 
bly overlying the third, however, is the compact limestone of the La- 
ventille Hills and the small islands to the westward of Port of Spain. 
This is entirely distinct from the crystalline limestone and undoubt- 
edly belongs to a more recent epoch than any of the rocks to the 
northward; and hence Mr. Guppy is right in urging that it should no 
longer be included in the “ Caribbean Group.” ‘The compact lime- 
stone is rich in organic remains, but these are so obscure that it is only 
within the last decade that the fact of their existence has been cer- 
tainly recognized. We are indebted to Mr. Guppy almost solely for 
the little that is known of the paleontology of this rock. The fossils 
so far made out are small bivalves resembling Nucula, and casts of 
small univalves like Murchisonia and Loxonema. Besides these 
there are according to Mr. Guppy a massive reef-coral and many 
serpuline fossils. This author regards the limestone as probably Car- 
boniferous or Devonian, but I would assign it a greater age, the fos- 
sils that I have seen having a decidedly Cambrian aspect.1 The 
1 Mr. Guppy has provisionally identified two of the Gasteropods with the North 
American species, Murchisonia anna Billings and Murchisonia linearis Billings 
both Cambrian species. 
