Walking through the first of these you clambered down some slippery stairs into what was once a breathless subterranean vault hewn out of the soft and dry pumiceous rock and used, as was customary, for storing barrels and other paraphernalia.
In it occur pumiceous lapilli of the same material up to 2 centimetres in diameter.
The pumice-tuffs of Mount Thuku are non-calcareous, and exhibit greyish pumiceous lapilli in an abundant white matrix formed of fine pumice-debris.
They occur in one or two places as agglomerates, as in the vicinity of Mount Thuku on the north coast and near Undu Point; whilst they form “flows” overlying the pumiceous tuffs at Vunikondi.
I found no beds of coral limestone in the shore-agglomerates of this coast, nor does Dana in his description of the pumiceous formation of the cliffs of Mali Point make any reference to them.
On the coasts are exposed bedded pumiceous tuffs, steeply inclined and usually calcareous.
In the coast district between Tutu Island and the village of Naua, 3½ miles to the east, the same altered coarse pumiceous and trachytic tuffs, occasionally bedded and dipping W.
It should, however, be not forgotten that vesicular and pumiceous materials may be discharged during a submarine eruption.
I found it to be composed from the foot to the summit of white pumiceous tuffs without any evident arrangement.
There is no difficulty in conceiving that the pumiceous mud, if so thrown out, may have set into a kind of stone on drying, just as some cements, composed of volcanic ashes, are known to consolidate with facility.
Portions, therefore, of this lava were either thrown out by explosions, or torn off by the waves, during the deposition of the pumiceous strata beneath the sea.
The white pumiceous mudstone, with its abundant gypsum, belongs to the same general epoch with the underlying fossiliferous mass, as may be inferred from the shells included in the intercalated layers at Nuevo Gulf, S.
Professor Ehrenberg has examined this mudstone for me: he finds in it three already known microscopic organisms, enveloped in a fine-grained pumiceous tuff, which I shall have immediately to describe in detail.
The cone which now bears the name of Vesuvius was probably formed during the celebrated eruption of 79, which buried under its showers of pumiceous ashes the cities of Pompeii and Herculaneum.
One white ribbon- like layer of decomposed, pumiceous breccia, was curiously bent into deep unbroken curves, beneath each of the large fragments in the superincumbent stratum.
Pumice occurs in great quantity; and there are conglomerates, or rather breccias, wherein fragments of trachyte are bound together by pumiceous tuff, or sometimes by silex.
Upon this rests a pumiceous breccia and conglomerate, with angular masses of trachyte, and some quartz pebbles.
Beudant, to dig into any of thepumiceous deposits of these mountains without meeting with opalized wood, and sometimes entire silicified trunks of trees of great size and weight.
The ruined villa, smashed and charred, stood with its walls half buried in ash and lapilli, among which were partly smashed pumiceous lava projectiles.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "pumiceous" in a variety of sentences. We hope that you will now be able to make sentences using this word.
