Because of the varied topography, diversity of plant life, and geographical locations, the canyon affords an ideal habitat for wildlife. Some of the mammals that occur here are the coyote, porcupine, jackrabbit, cottontail rabbit, raccoon, opossum, ringtailed cat, striped skunk, gray fox, white-footed mouse, woodrat, and bat. Mammals that were once common but are now absent or extremely rare are the bison, black bear, black-footed ferret, lobo wolf, cougar, and bobcat. The moose and American elk were introduced into the canyon but are no longer to be found. White-tailed deer, mule deer, and aoudad sheep have also been introduced and are still present. The mule deer is the most common. A great many types of birds are found either as residents of or migrants to the canyon. A few are the golden eagle, red-tailed hawk, sparrow hawk, Mississippi kite, turkey vulture, blue quail, killdeer, nighthawk, roadrunner, red-headed woodpecker, golden-fronted woodpecker, canyon wren, mockingbird, robin, cardinal, meadowlark, Bullock’s oriole, painted bunting, white-crowned sparrow, and lark sparrow. HISTORY OF MAN IN THE AREA Archeological studies indicate that the earliest known inhabitants of Palo Duro Canyon lived in the canyon from about 10,000 to 5,000 B.C. These early men hunted bison and now-extinct elephant-like mammoths that roamed the area during the Pleistocene Ice Age. Their stone weapons and artifacts have been found in the canyon. Presumably these primitive people, like those who came later, were attracted by streams and springs in the canyon, and by game that came to feed there. Rock exposed in the canyon provided material for tools and weapons. Through the centuries, various tribes of Plains Indians, including Apache, Cheyenne, Arapahoe, Kiowa, and Comanche, made use of the canyon as a camping ground. After the arrival of the white man, the canyon became a favorite resting place for buffalo hunters and Indian traders who travelled the Plains. White men first established residence there in 1876. The last Indian battle in Texas was fought in the canyon south of the Park. Col. Ranald Mackenzie and his raiders, on September 25, 1874, attacked a large encampment of Comanche, Cheyenne, Kiowa, and Arapahoe in the canyon. They destroyed about 100 lodges and 1400 horses and mules. The damage inflicted was severe and by the following spring most of the Indians were returned to the reservation in Oklahoma. GEOLOGIC HISTORY The age of the earth is calculated in terms of billions of years. For convenience, geologic time is divided into units, called PERIODS, of different lengths (Figure 1). Sediments deposited during each period and the fossilized remains of animals and plants found in these sediments give a partial record of the events and life of that period.