Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/101



These strata appear to alternate to a great depth; they lie horizontally, and seem to run through the whole extent of the hills The stratification in the west side of the hill is nearly the same as the above, but in the upper stratum of slate-clay nodules of reddish gypsum are intermixed, and in the lower gypsum is disposed in thin irregular strata of amorphous fracture.

The nodules of gypsum contain numerous dark reddish brown crystals of selenite. Similar nodules are also found in the hillook on which Kelso is built, imbedded in blue shale. The marl of Roxburghshire, when dry, is of a dirty blueish white colour, containing small bivalve shells.

In Mellendean burn the strata, particularly on the eastern side, are exposed to the depth of 60 or 70 feet, and consist of

1. Gravelly soil,

2. Marl,

3. Blue and brown slate-clay, alternating with limestone, which contains a large proportion of sand.

Two hundred yards further up the burn, the strata in its bottom consist of very hard bastard limestone, that is, limestone containing a large proportion of sand. The beds lie horizontally. The uppermost stratum in the bank near the entrance of the Dean is composed of amygdaloid. Wacké, and amygdaloid with a basis of wacké are not uncommon in the valley of the Tweed, where they appear to occur between beds of sandstone, as may be seen at Sprouston Ferry, at the Rapids about 3 miles above Kelso, and at a fall of the, river Tiviot about a mile above the same town.

The covering of Sprouston quarry is of the same kind of sandy and gravelly soil, as generally covers the vale of the Tweed. The sandstone rock of the quarry appears to be of limited extent, and of an irregular oval form, being about 300 yards long and 200 yards