Oreodon, an animal allied in some things to the camel, and in others to the tapir family. Another animal of a tapir-like appearance, but called by geologists Lophiodon, also lived during this period, and loft his bones—in the muddy lake-margins to become part of earth's history. Also, a peccary of large size, and an animal bearing some resemblance to the horse, called the Anchitherium—found also in France, and in the Mauvais Terres of Nebraska.
Following this age, was one of volcanic action and the outpouring of immense quantities of ashes and lava. By the lava-streams issuing from the Blue Mountains new barriers were raised, dividing the northern portion of the great lake of Eastern Oregon more completely from the southern, which, by reason of superior drainage, was the first to become dry land. The lake on the northern side of the Blue Mountains remaining longest a lake, continued to receive the drift of its shores for a longer period, and consequently offers a more perfect record of the changes which took place through all the Tertiary periods. Several of the strata formed in this lake are of pure volcanic ashes, still rough as pumice-stone to the touch.
Thus, this Middle Tertiary period was closed in violence. Volcanic fire, earthquake-shocks, and molten lava destroyed and blotted out all forms of vegetable and animal life. The ages roll on, and once more living forms of plant and animal haunt the shores of these shallowing lakes. The oak, the yew, the willow, have left their prints in the sedimentary rocks; and the bones of new creations of animal life, such as the camel and the horse, accompany them. But these, too, in turn suffer extinction by violence; the whole country being covered more than thirty feet deep in volcanic
