Fossil "Nests" in the Brownville Limestone at Admire Junction, Kansas

Abstract

In connection with the construction of two new highways, U. S. 50 N. and Kansas 11 at Admire Junction in Lyon county, Kansas, a diversion channel was excavated through the bed-rock in order to take care of the flood water of One H,u,ndred and Forty-two Mile Creek. (Fig. 1 A). In the process of building this diversion channel a portion of the surface of the Brownville limestone was exposed. The Brownville limestone is a light bluish to dark gray rock, varying in texture from dense, compact to crystalline. Its thickness at Admire Junction is 2Y2 feet and is composed of two massive beds which show large vertical joints. Fossils are abundant, especially a very fragile thin-shelled brachiopod belonging to the genus marginifera. Chonetes crinoid stems and cup-coral are also present in more or less abundance. Above and below the limestone are greenish to grayish shales belonging to the Aspinwall and Poney Creek shale members respectively. (Fig. 1 B). The upper surface of the Brownville limestone is smooth but irregular. The irregularities consist of shallow depressions which have no definite shape and orientation. ~Several clay seams or partings, irregular in outline, are visible in the limestone when seen in cross-section. Scattered over the entire floor of this recently exposed Brownville limestone surf,ace, approximately 18,000 square feet in area, are at least 80 patches of concentrated fossil remains described below. The Brownville limestone is of Pennsylvanian age and at present is cllassified by the Kansas State Geological Survey (1) as belonging to the Wabaunsee group of the Virgil series.