Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 8, 2025
Scoriaceous lava in part converted into an amygdaloid. One-half is scoriaceous, the pores being perfectly empty; the other part is amygdaloidal, the pores or cells being mostly filled up with carbonate of lime, forming white kernels. This term has a somewhat vague signification, having been applied to all melted matter observed to flow in streams from volcanic vents.
We spent forty-two and a half hours, paddling at the rate of five miles an hour, in coming from Linyanti to the confluence; there we found a dike of amygdaloid lying across the Leeambye. This amygdaloid with analami and mesotype contains crystals, which the water gradually dissolves, leaving the rock with a worm-eaten appearance.
The grunstein, which farther north was less granulous, and passed into serpentine, here assumes a very different character. It contains balls of mandelstein, or amygdaloid, eight or ten inches in diameter. These balls, sometimes a little flattened, are divided into concentric layers: this is the effect of decomposition.
This last formation resembles the tufas of Pausilippo, and the strata of puzzolana, which I found in the valley of Quito, at the foot of the volcano of Pichincha. The amygdaloid has very long pores, like the superior strata of the lavas of Vesuvius, arising probably from the action of an elastic fluid forcing its way through the matter in fusion.
She listens as to a fairy tale, and then I tell her of the stellar crystals concealed in the rough crust of the amygdaloid. She puts it away, and says I shall break it for her when we get home. We have traveled a long way, by different paths, since then, but it has never been broken never will be broken now.
The grunsteins, which begin again to the south of these slates, appear to me to differ little from those found north of the ravine of Piedras Azules. I did not see there any pyroxene; but on the very spot I recognized a number of crystals in the amygdaloid, which appears so strongly linked to the grunstein that they alternate several times.
J.D. Dana, in an excellent paper on Trap-rocks "Edinburgh New Philosophical Journal" volume 41 page 198, has argued with great force, that all amygdaloidal minerals have been deposited by aqueous infiltration. I may take this opportunity of alluding to a curious case, described in my work on "Volcanic Islands," of an amygdaloid with many of its cells only half filled up with a mesotypic mineral.
Together with the cavities formed by amygdaloid chambers and crevices caused by erosion, they give the cliffs the appearance of a huge, irregular honeycomb.
It is surrounded by pyroxenic amygdaloid; it would no doubt be seen below, issuing immediately from gneiss-granite, like the phonolite of Biliner Stein, in Bohemia, which contains fragments of gneiss embedded in its mass.
Suddenly wheeling round therefore to the right we quitted the open sea, and dived down a long grey lane of water that ran on as far as the eye could reach between two lofty ranges of porphyry and amygdaloid.
Word Of The Day
Others Looking