Northward along the Walnut, steep bluffs and eroded gulleys characterize both sides of the river, especially in southern Cowley County. Two massive limestones, the Fort Riley and the Winfield, form the bluffs in most places. The well-defined Winfield limestone is persistent on the west bank of the river across the entire county. The Walnut has only a few small tributaries in the southern half of Cowley County (Fig. 1). In the northern half, however, it is joined from the east by Timber Creek and Rock Creek. Timber Creek drains a large level area, formed by the eroded upper portion of the Fort Riley limestone, in the north-central portion of the county. The gradient of Timber Creek is 12.9 feet per mile. The gradient of the Walnut River is only 2.3 ft. per mile from its point of entrance into the county to its mouth. [Illustration: FIG. 1. Map of Cowley, Chautauqua and Elk counties, Kansas, showing the streams mentioned in the text.] Grouse Creek, like the Walnut, has formed a valley of one to three miles in width, rimmed by prominent wooded bluffs. Those on the west side are capped by the Fort Riley limestone with the resistant Wreford and Crouse limestones forming lower escarpments. On the east side the Wreford and Crouse limestones provide the only escarpments along the stream above the Vinton community, except for occasional lower outcrops of Morrill limestone. Below Vinton the Fort Riley limestone again appears, capping the hills above the Wreford limestone. The headwaters of the western tributaries of Grouse Creek are generally in the Doyle shale formation; the eastern tributaries are in the Wreford limestone, Matfield shale, and Barnestone limestone formations. The gradient of Grouse Creek is 9 ft. per mile, of Silver Creek 14.6 ft. per mile, and of Crab Creek 14.4 ft. per mile. The Big Caney River (Fig. 1), having a gradient of 15.4 ft. per mile in the area studied, drains an area with considerable geological and topographic variation. The main stream and its western tributaries originate in Permian formations, whereas the eastern tributaries originate in Pennsylvanian formations. Cedar Creek is exemplary of western tributaries of Big Caney. This creek arises in the Wreford limestone, as do several nearby tributaries of Grouse Creek. Although the Grouse tributaries descend through only part of the Council Grove group, Cedar Creek flows downward through the entire Grove, Admire, and Wabaunsee groups and part of the Shawnee Group (Moore, 1951). In only 15 miles, Cedar Creek traverses formations comprising more than 60 per cent of the entire exposed stratigraphic section in Cowley County. Bass (1929:16) states that reliefs of 350 feet within a mile are present in parts of this area.