. 
rowKE] THE LANSING SKELETON A475 
different layers being approximately parallel with the surface of 
the mass. It seemed to be due partly to talus from the cliff and 
partly to detritus carried down through a ravine from the hill to 
the south and deposited where the force of the water was checked 
on the comparatively level floor of limestone and shale, which is 
marked third and fourth on the list. 
The first chamber excavated (A) was a continuation toward the 
south of the original tunnel. The apparent difference in length of 
the two sides, as shown in the sections, Figures 10 and 18, arises from 
the fact that the end wail of the tunnel was not at a right angle to 
its direction, this obliquity being rectified in the extension. 
Ji was found more convenient to remove the material here in two 
sections. The first had a width of 7 feet, beginning at the west wall 
of the tunnel and extending a foot east of the central line. This cut 
Fic, 10.—Section of west side of chamber A 
was carried to the end before the remaining 5 feet was touched. At 
the east side of the section the stratified shale, next above the bed 
rock, had a thickness of 20 inches, while the stratum of mingled blue 
clay and stones overlying it measured about 25 inches. Both thinned 
toward the west; the shale to such a degree that it entirely disap- 
peared, allowing the clay, reduced to 16 inches at the west wall, to 
rest directly on the bedrock. 
As the digging progressed the line of contact between the shale 
and the rock floor bore quite regularly toward the west side of the 
excavation, which it reached at 314 feet from the face. A slab 2 feet 
long and 5 inches thick, belonging in the blue clay, lay upon the bed 
rock, its straight margin almost coincident with the line of the wall; 
the shale began in a feather edge at the inner side of this slab and 
rose gradually and evenly to the end of the cut, a distance of 9 feet, 
where it attained a thickness of 13 inches. The clay also became 
somewhat heavier, measuring 22 inches. The rocks included in the 
clay increased in numbers; at first they did not seriously interfere 
with the work, while at the end of the excavation it was difficult to 
find an opening for a pick; the quantity of stone being greatly in 
excess of the amount of clay. 
A section of the west side is presented in Figure 10. 
