AKTICLE I. 



DESCRIPTION OF A SKULL OF MEGALONYX LEIDYI, n.sp. 



BY JOSUA LINDAHL, Ph.D., 



SrBIKGFIELD, IT,L. 



Read before the American Philosophical Society, January 2, 1891. 



The specimen to be described on the following pages belongs to Bethany Col- 

 lege, Lindsborg, Kansas. It was placed in my hands for description, three years 

 ago, by Prof. J. A. Udden, at that time holding the chair of ]!:^ataral History in 

 Bethany College, and I wish herewith to express my obligation to the President of 

 the said institution, the Rev. C. A. Svensson, for having allowed me to retain it so 

 long, no less than to Prof. Udden, who first offered me this opportunity, and who, 

 at my request, has communicated a geological sketch of the locality where it was 

 discovered. 



This is his letter : 



Dr. J. LiNDAHL, Springfield, 111. : 



Dear Sir : — The fossil skull of Megalonyx, which I sent you three years ago, was found by a man in excavating a 

 sand pit near the southwest corner of Harper township, in McPherson county, Kansas. 



The watershed between the Kansas and the Arkansas systems runs through McPherson county from east to west. 

 Near the centre of the county it crosses at right angles a shallow trough about ten miles wide, which contains a series 

 of small, undrained basins, and is known by well diggers in the county as the " old river bed." This trough has for- 

 merly been one hundred and twenty five feet deeper than it now is, being filled to that extent by sediments burying 

 the red shales into which it is cut. Taken in ascending order, these sediments consist of (1) gravel and sand, contain- 

 ing rolled boulders of clay and angular fragments of cretaceous shales of various sizes up to a weight of a ton and 

 more (from ?iear the bottom of this gravel the skull was taken) ; (2) a stratum of clay, observed only in two places, and 

 not known to be continuous over any considerable area ; (3) a stratum of volcanic dust several feet in thickness, seen 

 at six different localities, extending twelve miles in a line across the trough ; (4) a fine dull orange-colored loam, up- 

 wards of seventy-five feet in thickness, and occasionally resembling loess. 



A. P. s. — VOL. xvn. A. 



