The geological structure and mineralogical pro ductions of this part of Arabia are in a great measure unknown. In the mountains about Mecca and Medina the predominant rocks are of gray and red granite, porphyry, and limestone. This is also the case in the great chain that runs southward towards Maskat ; only that in the ridge that rises behind the Tehama there is found schistus and basalt instead of granite. Traces of volcanic action may be perceived around Medina, as also at Aden and in many other parts of the peninsula. Hot springs are of frequent occurrence on the Hadjee or pilgrim road to Mecca. The ancients believed that Arabia yielded both gold and precious stones, but Niebuhr doubts if this ever was the case. The most valuable ore found now is the lead of Oman : what is called the Mocha stone is a species of agate that comes from India. The native iron is coarse and brittle ; at Loheia and elsewhere there are hills of fossil salt. The botany of Yemen was inves tigated by Forskal, one of the fellow-travellers of Niebuhr. Arabia Felix has always been famous for frankincense, myrrh, aloes, balsam, gums, cassia, etc.; but it is doubtful whether the last mentioned and other articles supposed to be indi genous were not imported from India. Here are found all the fruits of temperate and warm climates, among which the date, the fruit of the palm-tree, is the most common, and is, along with the species of grain called dhourra, the staple article of food.
But the most valuable vegetable production is coffee (Arab. hahweh, an old term for wine, the fruit being called bunn) ; for Yemen, if not its native country, is the habitat where it has reached the greatest state of perfection. Cultivation here is not confined to the plains, but is carried up the sides of the mountains, which are laid out in ter races, and supplied with water by means of arti ficial reservoirs. In the animal kingdom Arabia possesses, in common with the adjacent regions, the camel (the 'living ship of the desert'), panthers, lynxes, hyaenas, jackals, gazelles, asses (wild and tame), monkeys, etc. But the glory of Arabia is its horse. As in no other country is that animal so much esteemed, so in no other are its noble qualities of swiftness, endurance, temper, attach ment to man, so finely developed. Of the insect tribes, the locust, both from its numbers and its destructiveness, is the most formidable scourge to vegetation. The Arabian seas swarm with fish, sea-fowl, and shells ; coral abounds in the Red Sea, and pearls in the Persian Gulf.