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were taken from a bed of sandy clay twenty feet above the present bed of the creek, at a point about fifteen miles east of north of Big Springs. In the same bed were found two species of the horse, fragments of a large animal the size of an elephant, and of a small animal the size of a rabbit. This bed rests upon a conglomerate composed of small siliceous pebbles containing water-worn Cretaceous fossils, and the conglomerate rests upon the cross-bedded sandstone of the Triassic.

PECOS VALLEY.

Between the Pecos river and the western escarpment of the Staked Plains, opposite the town of Eddy, New Mexico, there is a belt of country about twenty miles wide covered by deep drifting sand, and overgrown with shin oak brush. In the midst of this sandy belt, nearly west of Eddy, is a salt lake, the banks of which on the west and south sides are Triassic. On the north side, about twenty feet from the bottom, is a bed five or six feet thick of fine white hardened sandy clay, in which were found the shells mentioned as coming from this locality. These shells were identified by Dr. V. Sterki, and a short paper relating to them was published by him in the Third Annual Report of the Texas Geological Survey (pp. 263-265)), and is referred to here for the purpose of comparison with the forms west of the Staked Plains.

The only correction to be made in the list then published is that the shell referred to as Vallonia costata, Mull. var., should be V. gracilicosta, Rein., specific determination having been made since the publication of that report.

LAKE ON PLAINS.

This lake is about one mile south of the head of Tule Canyon. It is in one of the depressions which occur at various places on the Staked Plains, and is supplied with water by rainfall only, and as a matter of course is very often dry. At the time of my visit the water was not over a foot deep at any place. The shells taken here were all living.

TULE RANCH.

The place mentioned as Tule Ranch is about six miles above the head of Tule Canyon, and is on Tule creek. The creek has cut a channel into the beds of the Tertiary at this place to the depth of about thirty feet. In the canyon is a constant stream of water flowing from numerous small springs.

The shells taken from this place were obtained from the banks of that stream, and from the stream itself. They are all evidently living shells.