trap-rock

It comes from beneath the trap-rock, of which I shall have to speak when describing the geology of the entire country; and as it usually issues at a temperature of 72° Fahr., it probably comes from the old silurian schists, which formed the bottom of the great primeval valley of the continent.

Missionary Travels and Researches in South Africa

In the middle was the caldron of the torrent, called the “Scarfe,” with the sheer trap-rock, which is green in the sunlight, like black night flung around it, while a snowy wreath of mist (like foam exhaling) circled round the basined steep, or hovered over the chasm.

Mary Anerley

The 16th of May saw us journeying over the plain which lies between Ugombo and Mpwapwa, skirting close, at intervals, a low range of trap-rock, out of which had become displaced by some violent agency several immense boulders.

How I Found Livingstone

Immediately over our camp its waters ran over a very hard “trap-rock” of a black colour, the soil a stiff loam.

Narrative of an expedition undertaken for the exploration of the country lying between Rockingham Bay and Cape York

The hill on which I stood consisted of trap-rock, and seemed to be almost the western extremity of

Journal of an Expedition into the Interior of Tropical Australia

The summit consisted of trap-rock in nodules, and, towards the highest point, was much broken.

Journal of an Expedition into the Interior of Tropical Australia

I rode to one and found it consisted wholly of trap-rock in nodules.

Journal of an Expedition into the Interior of Tropical Australia

_The Weehawken Tunnel_ -- This tunnel is now being cut through the trap-rock for the New York, Ontario, and Western Railroad, and will be completed in a few months, but will, probably, be available as a mineralogical locality for a year to come.

Scientific American Supplement, No. 344, August 5, 1882

In many localities, the coals and lignites of different ages have been exposed to local influences -- such as the outbursts of trap-rock, or the metamorphism of mountain chains -- which have hastened the distillation, and out of known earlier groups have produced the last.

Scientific American Supplement, No. 362, December 9, 1882

Then he told them that good gravel, tough limestone and trap-rock were good road materials.

The Library of Work and Play: Gardening and Farming.