webb] ARCHAEOLOGICAL SURVEY OF NORRIS BASIN 19 



tween the curved striations seemed to indicate that in making the 

 primary mound dirt had been added in level layers, and by this 

 means the mound had been built up to the level of the secondary 

 floor. The secondary floor was uniformly 4^ feet above the pri- 

 mary on all faces, but it sloped to the northwest slightly, as did the 

 original humus layer at the base of the mound. After the secondary 

 floor had been plotted and photographed, workmen were stationed 

 around the outer edges of the vertical block of earth supporting the 

 secondary floor and told to remove the earth in 1-foot stages. When 

 shovels were forced into the earth just outside the line of post 

 molds the striated yellow and red clay wall caved off vertically in 

 enormous slabs from the top down to the level of the primary floor, 

 leaving a grayish colored wall, as shown in plate 7, a. In other 

 words, there appeared to be a vertical cleavage plane extending from 

 the primary to the secondary floor on all four sides, and situated just 

 beyond the post molds. A wedge (pi. 7, b) was cut into the southeast 

 face of the vertical blocks in an endeavor to determine whether the 

 cleavage line was formed by the settling of earth immediately over 

 the remains of the burned structure, which was already making its 

 appearance around the outer edges of the primary floor. The slant- 

 ing faces of this wedge failed to show any striations whatever. The 

 earth beyond the cleavage plane was darker in color and did not con- 

 sist of a pure red-and-yellow clay as did that encountered outside 

 the cleavage plane. Furthermore, there appeared to be no further 

 indication of curved striations at the corners, nor were there any 

 horizontal striations. It appeared that a cube of earth had been 

 constructed over the primary floor. Following this, clay had been 

 thrown up against this cube at the corners, thus presenting the 

 appearance of four primary mounds beyond the cleavage plane. 



This condition might readily be attained if we may assume a 

 wooden structure which had a heavy covering of earth on the roof. 

 The great weight of the earth covering would have necessitated con- 

 siderable bracing of the side walls of the building. This bracing 

 was done by piling up earth at the four corners outside the walls. 

 Thus small mounds, one at each corner, were formed by the earth 

 piled up against the building. Each of these mounds, however, was 

 in fact only three-fourths of a mound — the other quadrant being 

 taken up by the corner of the building. When and if the roof sup- 

 ports rotted and the whole mass fell like a large square block and 

 covered the floor below, these corner mounds would remain, and the 

 walls of the building would be a vertical plane of cleavage between 

 the central block of the mound, which was formerly on the roof, and 

 the earth piled against the walls. It is believed that this is what 

 happened in the construction of this mound. The reasonableness of 



