Page:Popular Science Monthly Volume 73.djvu/562

558 continent the record of the great land fauna of the Permian age is very faulty and imperfect. It is only in some exceptional place where large quantities of bones were swept together under favorable conditions that they have been preserved and such an exceptional depository occurs in northern Texas.

When the Appalachian Mountains were raised an extension of their southern end reached across what are now Arkansas and Oklahoma, terminating in the Wichita Mountains in western Oklahoma. North of this range rose a broad upland reaching from the Rockies to the Appalachians and to the Canadian line on the north; south of the mountains a shallow sea reached nearly to their base, and some

great rivers, from the mountains and the uplands, poured their flood waters into the sea and built up a great delta. The remains of animals which haunted the banks of the rivers were swept into them in time of flood and carried out to be deposited in the delta, which covered most of what is now Wichita, Archer and Willbarger counties in the state of Texas. Naturally most of the remains which found their way into the streams were already fragmentary, as they had rotted on the bank and been torn by predatory animals, but in their course to the sea they were farther disintegrated, so that, rolled by the rivers and beaten by the waves, they sank to their burial as little more than water-worn fragments; ends of limb bones, isolated vertebræ and broken skulls which do