wards the south and east. This valley is principally occupied by the red sandstone, which, in those directions terminates against the mica slate, forming the base of Knocklead (the round-backed mountain seen in the distance) and extending thus far in continuation of the primitive district already described in Cushleak. Between 4 and 500 feet on the ascent of this mountain, a bed of primitive limestone may be traced. Above this, through an interval of about 400 feet, the strata have not been ascertained; but probably the red sandstone, and perhaps also the lias and mulattoe, may be found in this space, since the chalk appears at the elevation of between 8 and 900 feet; and the whole is crowned by a cap of basalt, 980 feet in thickness.
On the eastern side of Ballycastle bay, the basalt rises into low cliffs, and the substratum of chalk emerges from the level of the sea, but soon sinks again.[1] In this interval the vein of wacke and compact limestone, described by Dr. Berger, page 172, occurs; from hence to Kenbaan there is nothing that requires particular attention.
- ↑ I cannot more clearly describe the general arrangement of the chalk and basalt, as displayed on the Antrim coast, than by transcribing the following paragraph from the late Mr. Hamilton's Letters, a work which may be classed with Mr. White's well-known
letters on the Natural History of Selborne, as one of the most elegant models which our language possesses of writing upon such subjects; and as affording one of the few examples which prove that they are capable of being treated in such a manner as shall
render them not only interesting to the enquirer into the detail of science, but engaging to the man of general information and cultivated taste.
“ The northern coast of Antrim seems to have been originally a compact body of limestone, (chalk) considerably higher than the present level of the sea; over which, at some later period, extensive bodies of vitrifiable stone have been superinduced in a state of softness. The original calcareous stratum appears to be very much deranged and interrupted by these incumbent masses. In some places it is depressed greatly below its ancient level. Shortly after it is home down to the water's edge, and can be traced under its surface: by and by it dips entirely, and seems irrecoverably lost under the superior mass. In a short space, however, it begins to emerge, and after a similar variation recovers its original height.”—Letters on the Coast of Antrim, page 6.
