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They are formed of a cavernous greyish green limestone of crystalline texture, mixed with some spangles of mica, and are destitute of shells. We see in them masses of hardened clay, black, fissile, charged with iron, and covered with a crust, yellow from decomposition, like basalts and amphiboles.

The lava streams, therefore, must be of later date than the depressions they fill. And yet, where they have thus temporarily dammed the Jordan and the Jermuk, these streams have had time to cut through the hard basalts and lay bare the beds, over which, before the lava streams invaded them, they flowed.

Both these rocks are composed of triclinic feldspar and augite with more or less olivine, magnetic or titaniferous oxide of iron, and usually a little nepheline, leucite, and apatite; basalt usually contains considerably more olivine than melaphyre, but chemically they are closely allied, although the melaphyres usually contain more silica and alumina, with less oxides of iron, lime, and magnesia, than the basalts.

A few islands rose to heights of 300 or 400 feet in McMurdo Sound, and these had no snow on them worth speaking of even in the winter. The visible land was of black or chocolate-brown, being composed of volcanic tuff, basalts, and granite.

Every particle of moisture had long since evaporated; even chemical combinations had been dissolved by the alternations of heat and cold known only on earth to the chemist in his laboratory. Only the hardest rocks, such as granites and basalts, remained.

"MY DEAR SIR Am I right in concluding, from the description which; you were so kind as to send to me, that the lignite bed, with its superincumbent basalts, lies above those particular columnar basalts which form the far-famed Giant's Causeway?

This projection will remain in sight until we reach Shuwak; and in places we shall see it backed by the basalts and lavas of the straightlined Harrah. Like yesterday's, the loose red sand is Hisma; and it is also scattered with Harrah lava. After a four hours' ride we halted to enable the caravan to come up.

At 10.20 A.M. we had passed out of the cultivated region to the Montijo, or Monte Verde, the laurel-region. The latter show the anatomy of the land tufas, lavas, conglomerates, trachytes, trachydolerites, and basalts of various kinds. Most of the rocks are highly magnetic, and are separated by thin layers of humus with carbonised plant-roots.

Amphibole, sometimes pure and forming intermediate strata, at other times mixed with granite, as in the basanites or basalts of the ancients, may, of itself, furnish all the iron contained in the black and stony lavas. This quantity amounts in the basalt of the modern mineralogists only to 0.20, while in amphibole it exceeds 0. 30.

In those days the rocks which are now the very bones and sinews of our mother Earth her granites, her porphyries, her basalts, her syenites were melted into a liquid mass.