Aims of the distributional study here reported on concerning the fishes of a part of the Arkansas River Basin of south-central Kansas were as follows:

(1) Ascertain what species occur in streams of the three counties.

(2) Ascertain habitat preferences for the species found.

(3) Distinguish faunal associations existing in different parts of the same stream.

(4) Describe differences and similarities among the fish faunas of the several streams in the area.

(5) Relate the findings to the over-all picture of east-west distribution of fishes in Kansas.

(6) List any demonstrable effects of intermittency of streams on fish distribution within the area.

Cowley and Chautauqua counties form part of the southern border of Kansas, and Elk County lies directly north of Chautauqua. The following report concerns data only from those three counties unless otherwise noted. They make up an area of 2,430 square miles having a population of 50,960 persons in 1950 (55,552 in 1940, and 60,375 in 1930). The most populous portion of the area is western Cowley County where Arkansas City with 12,903 inhabitants and Winfield with 10,264 inhabitants are located. Each of the other towns has less than 2,000 inhabitants. In the Flint Hills, which cross the central portion of the area surveyed, population is sparse and chiefly in the valleys.

Topographically, the area is divisible into three general sections: the extensive Wellington formation and the floodplain of the Arkansas River in western Cowley County; the Flint Hills in the central part of the area; and the "Chautauqua Hills" in the eastern part. The drainage pattern is shown in Figure 1.

The Wellington formation, which is devoid of sharp relief, borders the floodplain of the Arkansas River through most of its course in Cowley County. A short distance south of Arkansas City, however, the Arkansas is joined by the Walnut River and enters a narrow valley walled by steep, wooded slopes. Frye and Leonard (1952:198) suggest that this valley was originally carved by the Walnut River, when the Arkansas River flowed southward west of its present course. They further suggest that during Nebraskan glacial time the Arkansas probably was diverted to the rapidly downcutting Walnut. The Arkansas River has a gradient of 3.0 ft. per mile in Cowley County. This gradient and others cited were computed, by use of a cartometer, from maps made by the State Geological Survey of Kansas and the United States Geological Survey.

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.

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.

Large terraces of limestone characterize the eastern flank of the Flint Hills, which the western tributaries of Big Caney drain. Most striking is the Foraker limestone. It characteristically consists of three massive members in Cowley County, the uppermost of which forms the prominent first crest of the Flint Hills. As the rapid-flowing western tributaries of Big Caney descend over these successive limestone members, large quantities of chert and limestone rubble are transported and deposited in stream beds of the system. In many places the streams of the Big Caney system flow over resistant limestone members, which form a bedrock bottom. The eastern tributaries of Big Caney drain, for the most part, formations of the Wabaunsee group of the Pennsylvanian. Most of these streams have lower gradients than those entering Big Caney from the west. The tributaries of Big Caney, along with length in miles and gradient in feet per mile, are as follows: Spring Creek, 7.1, 54.5; Union Creek, 6.3, 42.9; Otter Creek, 14.6, 27.4; Cedar Creek, 11.6, 31.0; Rock Creek, 15.9, 26.5; Wolf Creek, 9.3, 17.2; Turkey Creek, 8.5, 26.4; Grant Creek, 13.9, 23.4; and Sycamore Creek, 8.9, 27.0.

Spring Creek and Union Creek are short and have formed no extensive floodplain. The high gradients of these creeks are characteristic also of the upper portions of several other tributaries such as Cedar Creek and Otter Creek.

Middle Caney Creek (Fig. 1) has its source in the Wabaunsee and Shawnee groups of the Pennsylvanian but its watershed is dominated by the "Chautauqua Hills" of the Douglas Group. This area is described by Moore (1949:127) as "an upland formed by hard sandstone layers." The rough rounded hills supporting thick growths of oaks differ in appearance from both the Big Caney watershed on the west and the Verdigris River watershed on the east. The gradient of Middle Caney in Chautauqua County is 10.8 feet per mile. Its largest tributary, North Caney Creek, has a gradient of 15.5 feet per mile.

The Elk River Basin resembles the Big Caney River Basin topographically. Elk River has a gradient of 14.4 feet per mile.