Note on a Giant Kansas Calamite and the Ottawa Fossil Forest

Abstract

WALTER H. SCHOEWE State Geological Survey, University of Kansas, Lawrence. Calamites are Carboniferous fossil horsetail rushes which are represented today by about 25 species of the single genus equisetum. Calamites were plants with numerous, hollow, jointed, and ribbed stems which grew in wet or swampy sandy soils in jungle-like areas resembling the modern southern canebrakes or bamboo thickets. At the nodes along the stems were branchlets which were often arranged in whorls, and these bore circlets of leaves at their nodes. Unlike the modern horsetail rushes, which are generally less than three feet tall (except for a South American species that grows from 30 to 40 feet in height and is one inch in diameter), the Carboniferous calamites were very much larger than their living descendants. Calamite specimens less than six inches thick are common. Some calamites, however, attained diameters up to three feet and heights as much as 100 feet. This note is to record an unusually large or giant Kansas calamite which I observed last November (1943) while mapping and studying Thayer coal in the Chanute shale formation in eastern Kansas. The fossil plant is an internal sandstone mold consisting of a segment 34 by 28 inches in diameter and 8 inches thick. This specimen, therefore, approaches the maximum known size attained by calamites. On the basis of its diameters, this plant while growing might have reached a height of fully 100 feet. As far as I am aware this is the largest calamite specimen ever recorded for Kansas. It was found in Neosho County at a Thayer coal outcrop located near the head of a draw about two-tenths of a mile west of the sectionline road and approximately on the south line of the NE'4 sec. 9, T. 28 S., R. 18 E. A very interesting and unusually excellent exposure of calamites in situ occurs about two miles west of Ottawa, Franklin County, in a road cut on highway U. S. 50 S. between Ottawa and Emporia. At the outcrop are several calamites ranging from onehalf to three inches in diameter and from five to six feet tall. The calamites are in the form of internal sandstone molds, standing in a vertical or upright position with their lower parts rooted in the Ottawa coal (Fig. 1). The Ottawa fossil forest is especially note-