Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/191

 it runs to the extent of four hundred and sixty yards in a direction from north-east to south-west, coming up to the top of the hill towards the latter point, and falling down the opposite way. The pillars are five and six sided; a few have seven sides. I measured two of the largest size; one of them was three feet, the other two feet eight inches in diameter.

Along the slope of the hill, the pillars are so completely disengaged from the soil, that I could easily determine their angle with the horizon; I found it 22°.

On the main at Knocksoghey, the highest ridge of land between Ballycastle-bay and White-Park-bay, some flœtz-trap pillars, most of which are neatly defined, are quarried for building. Another quarry of the same rock has been opened at Ballynastrade near Ballintoy.

Croaghmore, one of the hummocks that lies at the greatest distance from the coast, is completely formed of an assemblage of pillars almost vertical, and jointed as is usually the case.

In the town-land of Craigahulliar, one of the most beautiful colonnades that can be seen lies under a mass of tabular basalt. Its extent is only one hundred and ninety feet, in a direction from east-north-east to west-south-west, presenting its façade towards the north-north-west: the pillars are from eighteen to fifteen feet in height, and the individual joints of which they are composed, one foot and a half; most of them are five-sided, others have four and six sides; they are remarkably sonorous.

I have remarked some rude attempts of the flœtz trap to assume a prismatic configuration at the bridge of Bushmills, at Magilligan, and on the north-west side of Donald-hill, but not distinct enough to be more particularly noticed.

It was natural to suppose that basaltic pillars, containing so