The valleys which penetrate into the sandstone supporting these trap rocks, have usually a sandy soil, while that of the more elevated portions, though inconsiderable in quantity, is not sandy nor intermixed with pebbles or gravel. Among the few scattered and scrubby trees met with in this district, are oaks, willows, and the cotton-wood; also a most interesting shrub or small tree, rising sometimes to the height of twelve or fourteen feet. It has dioecious flowers, and produces a leguminous fruit, making in several particulars a near approach to gladitschia; from which, however, it is sufficiently distinguished by the form of the legume, which is long and nearly cylindric, and by the seeds, which are enclosed in separate cells, immersed in a saccharine pulp, but easily detached from the valves of the legume. In these particulars it discovers an affinity to the tamarind of the West Indies. The legume or pod, which is from six to ten inches long, and near half an inch in diameter, contains a considerable quantity of a sugar-like pulp, very grateful to the taste when ripe. The leaves are pinnated, and the trunk beset with spines, somewhat like the honey locust, but the spines are simple. Our Spanish interpreter informs us, that it is found about Monterrey, and other parts of the internal provinces, where it must have been noticed by Humboldt, but we have not been able to have access to his account of it. In the afternoon we travelled {280} thirteen miles, descending along the valley in a south-east direction. We extended our ride farther than we had wished, finding no suitable place to encamp. After sunset we found a small puddle of stagnant water in the bed of the creek, which, though extremely impure, was not as bitter as that near which we halted in the middle of the day. Neither wood nor bison dung could be found, so that being unable to kindle a fire, we were compelled to rest satisfied with the eighth part of a sea biscuit each for supper, that being the utmost our supplies would allow. In the afternoon one of our hunters had killed a badger; this was all the game we had, and this we were compelled to reserve until we could make a fire to cook it.