On the 20th, at six o'clock in the morning we set out from Imserrha, and in two hours arrived at Rashid, where we were surprised to see the branches of the shrubs and bushes all covered with a shell of that species of univalve called Turbines, white and red; some of them from three to four inches long, and not to be distinguished by the nicest eye from those sea-shells, of the same species, which are brought in great quantities from the West India islands, especially St Domingo. How these came first in a sandy desert so far from the sea is a disquisition I shall not now enter into. There are of this fish great numbers in the Red Sea, and in the Indian Ocean; how they came upon the bushes, or at the roots of them, appears more the business of the present narrative. To confine myself to the matter of fact, I shall only say, that throughout this desert are many springs of salt-water; great part of the desert is fossile salt, which, buried in some places at different depths according to the degree of inclination of all minerals to the horizon, does at times in these fountains appear very near the surface. Here I suppose the seed is laid, and, by the addition of the rain-water that falls upon the salt during the tropical rains, the quantity of salt-water is much increased, and these fishes spread themselves over the plain as in a temporary ocean. The rains decrease, and the sun returns; those that are near springs retire to them, and provide for the propagation of future years. Those that have wandered too far off in the plains retire to the bushes as the only shelter from the sun. The intense heat at length deprives them of that shade, and they perish with the leaves to which they crept for shelter, and this is the reason that we saw such a quantity of shells under the bushes; that we found them otherwise alive in the very heart of the springs, we shall further circumstantiate in our Appendix, when we speak of mussels so found in our history of the formation of pearls. Rashid was once full of villages, all of which are now ruined by the Arabs Daveina. There are seven or eight wells of good water here, and the place itself is beautiful beyond description. It is a fairy land, in the middle of an inhospitable, uninhabited desert; full of large wide spreading trees, loaded with flowers and fruit, and crowded with an immense number of the deer kind. Among these, we saw a large one, like the antelope, his buttocks (a considerable way up his back) being covered with white, which terminated upon his thigh in a black line, drawn from the haunch down very nigh to the joint of his hind leg. These we had never seen before. They are called Ariel in Arabia, go in large flocks, are exceedingly swift; though, from the necessity of coming to water, and its only being found in particular places, they were an easy victim to those that watched for them at night.