38 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



Owing to a long-continued drought, the surface earth was very dry 

 and hard, requiring a pick to facilitate its removal, and even after 

 penetrating the crust the digging was by no means easy; but, apply- 

 ing ourselves to the task, we proceeded to open a trench four feet 

 wide by eighteen feet long, extending across the apparent center in a 

 direction approximately north and south. The earth composing the 

 mound is a stiff clay loam, for the most part homogeneous, but with 

 some scattered patches of a purer clay, and a thin layer of the same, 

 of varying thickness, which, about five feet below the surface, appeared 

 plainly, in section, on the hard perpendicular walls of the trench at its 

 northern end. Farther down, the earth became somewhat darker, as 

 of loam with a less admixture of clay, until, at a depth of ten feet, we 

 came upon a perfectly well-defined rloor, consisting of a layer of light- 

 yellow, sandy clay, about three inches thick, resting on the original 

 subsoil of compact pure clay. 



Thus far, no bones or other deposits had been found, save a mass of 

 rotten wood, the crumbling remains of what were, apparently, decayed 

 oak logs, which, about half way down and just north of the middle of 

 the trench, extended across and beyond it on either side, slanting down 

 toward the south, while just beneath them the clay stratum above men- 

 tioned dipped and disappeared. 



The fact that in most of the mounds of this group decayed oak wood 

 in considerable quantities is found, was mentioned by Mr. Pratt in his 

 report of the previous expedition. 



For convenience in throwing out the earth, about six feet of the 

 south end of the trench was at first but partially excavated, leaving a 

 temporary bench, and we proceeded to run transverse, arched galleries, 

 at the level of the floor, from the excavated part. These galleries were 

 from three to four feet wide and about four feet high, their arched 

 shape, together with the stiffness of their walls, making this method of 

 procedure comparatively safe. Nine galleries in all were dug, besides 

 numerous pockets and connecting passages, laying bare about five 

 hundred square feet of the base. In patches covering much of 

 the floor, to the south of the apparent center of the mound, was 

 a thin layer of a whitish ash, above which were several alternating 

 layers of a darker ash and soft earth, of varying thickness; and just 

 above these again, as seen plainly in section throughout the galleries 

 to the east and south, a continuous layer of rotten wood, as of logs 

 irregularly laid on after the mound had been built up about four feet. 

 This log covering, where present, dipped quite regularly outward, as it 

 would naturally do, following the curvature of the mound. Above 



