File:The Quarterly journal of the Geological Society of London (12981080983).jpg

1858..
HAEKNESS DOLOMITES .
101
quarry tkree very distinct masses of yellow magnesian Hinestone are
seen. One of these masses is represented in fig. 10. The bedding
Fig. 10. — Dolomitic Carboniferous Limestone, at Gasiuorlcs Quarry,
Corlc. Looking South.
The central Hght- tinted rock is dolomite
of the whole of the strata in this quarry, as before mentioned, is very
rudistinct ; but the general strike of the beds supports the conclu-
sion that the strata have an east and west range ; and, consequently,
the iacHnation of the strata must be either north or south, unless
they be vertical. This arrangement of the stratification would lead
us to expect that the dolomites would strike east and west also,
parallel to the ordinary limestone-strata, had these dolomites ori-
giuated from the same circumstances which have given rise to the
other limestones. So far is this from beiug the case, that we have
the dolomitic masses striking north and south ; and, as the jointing
is weE. developed in this quarry (more especially the north and south
joints), we find an intimate agreement between the direction of the
joints and the courses which these masses of dolomite assume.
These features, as to direction, are not confined to the Gasworks
quarry ; the same phenomena are apparent at the larger quarry at
Sunmierstown, also previously referred to (p. 92), and here likewise
the jointing is weU developed.