FOWKE] THE LANSING SKELETON 477 
tunnel, as will appear later. It is quite possible that, in spreading 
out near the mouth of the ancient ravine, storm water would so dis- 
tribute its force as to build up a small mound like this deposit. 
The regularity of the lamination and the absence of any appearance 
of crumpling or squeezing in the shale are opposed to the theory that 
it may have slipped from the cliff behind it; and so are the stratifica- 
tion, imperfect though it be, of the overlying clay, and the uniformity 
of inclination of the flat rocks included in the latter. 
Fic, 12.—Section of south end of chamber A 
Across the south end of this chamber—the wall which bounds the 
farthest extension of the tunnel—the shale for a space of 814 feet 
held about the same thickness of 13 inches as at the southwest corner ; 
it then diminished to 5 inches at the southeast corner. Similarly, 
the stratum of blue clay and rocks maintained its measure of 22 inches 
for about 5 feet, from which point it dropped to 13 inches. The 
Fic. 13.—Section of east wall in chamber A 
bedrock also dipped in the same direction, being 5 inches lower at 
the east wall than at the middle line of the cut. It was not entirely 
smooth and level over any part uncovered, having everywhere the 
slightly uneven surface characteristic of thin-bedded limestone. 
Figure 12 shows this end wall in its proper proportions, though 
the surface of the bedrock is not represented. 
A section of the east wall is shown in Figure 13. There are omitted 
from the illustration some tortuous thin streaks of lime-like matter, 
apparently segregations from the blue clay in which they occur. 
