24 ROYAL SOCIETY OF CANADA 
observed at a number of points throughout the southern portion of the 
island. 
The mineral known as Manjak or sometimes as Glance pitch, is found 
at several places, more specially near the town of San Fernando. While 
the petroleum of the district has a marked asphaltic base, this mineral 
is an almost pure asphalt. It occurs, however, in an entirely different 
manner from the oil deposits and from the asphalt of the Pitch lake. 
The whole of the Tertiary rocks seem to have been affected by movements 
apparently from north to south, by which the strata have been thrown 
into the series of folds just described. Usually these folds have taken 
place without any marked vertical displacement, since while indications 
of faults are visible at a number of points, such displacements do not 
appear to have been of any great extent. 
The deposits of Manjak and their mode of occurrence are very 
similar to those observed in connection with the albertite of south- 
eastern New Brunswick. In that province, however, the containing 
rocks are entirely different in age since they belong to the upper 
Devonian, in which the mineral occurs along a line of fissure extending 
nearly east and west near the crest of an anticline. This extends a 
distance of half a mile or more, and has been followed downward to a 
depth of 1,500 feet nearly vertical. 
In Trinidad and in Barbados similar fissures are found in the Ter- 
tiary shales and sandstone. Near San Fernando in Trinidad, the rocks 
of the Naparima hill are harder than those of the soft Tertiary, and 
though thrown into the anticlinal form have offered a certain amount 
of resistance against which the softer rocks have been crushed and fis- 
sures produced. The fissures thus formed have been filled with petro- 
leum either from the sides or from the bottom, which has evidently 
issued from beds of oil-bearing sandstone. Subsequently the volatile 
matter has escaped and the resulting mineral is an asphalt, often of high 
grade, the principal impurity being from particles of greyish shale or 
clay, derived apparently from portions of soft clay shales which have 
been traversed by the lines of fissure. In the New Brunswick beds the 
mineral is of greater purity, since the containing beds have not given 
off so readily such particles of shale from the sides of the fissure, owing 
to their greater hardness; but here the disintegration of the adjacent 
shales is also seen in the fact that the lower portion of the albertite vein 
is made up of a brecciated mass of angular fragments which are 
cemented by the albertite itself. In both countries the vein is affected 
by small displacements subsequent to their formation. 
Further resemblances in the character of the veins in Trinidad and 
New Brunswick are seen in the enlarged condition at different points. 
