Feb., 1907.] 
The Columbus Esher. 
69 
ridge has been eroded by a small branch of Xeil’s Run, which 
crosses it just north of Sixteenth Avenue. 
A cross section (Figs. 3 and 4) at the northern end exposed 
by the excavation for Woodruff Avenue shows it to be 128 feet 
wide and 16 feet, 8 inches high. Here it rests directly upon the 
bed rock, the Ohio Shale. The bottom layer of 12 inches con¬ 
tains a great number of angular and partly -water-worn pebbles 
of the adjacent shale (Fig. 4). The strata of the large central 
core dip outward from 20 0 to 45°. Here coarse and fine sand 
alternate with each other and with layers of coarse and fine 
gravel. On either side at the edges the stratification is some¬ 
what tumbled or disturbed. This is probably due to the melting 
away of the ice at the sides and the subsequent settling of this 
portion. The strata contain a few rounded pebbles of the Ohio 
Shale and neighboring limestones, but the great majority are of 
foreign rock. The sheet of till here caps these crumpled por¬ 
tions and even runs over the entire form. 
At Eighteenth Avenue the curbstone of the street does not 
reach the bed rock in the cut, but it was said to have been struck 
some 4 or 5 feet deeper. The height of the esker above the curb 
is 11 feet. As the ridge turns sharply to the southwest at this 
point the exact width was hard to determine, but it was taken to 
be 115 feet. The strata are deposited in a more uniform arch 
over the center with less distortion on the edges. Deeper ex¬ 
cavation, however, might show the edges to be distorted. The 
strata consist of alternate coarse sand and fine gravel. The whole 
is capped by till. 
Fig. 5. A diagram to show the cross section on the north side of 
Sixteenth Avenue, width 114 feet, height (exposed) 13 feet, 5 inches. 
The excavation for Sixteenth Avenue in the southern portion 
did not reach the bed rock (Figs. 5 and 6). Here it rises 13 feet, 
5 inches above the cut and spreads out laterally to a width of 114 
feet. The strata of the central portion are not laid down in 
such a uniform arch as those of the other two sections. Those 
of the eastern portion dipping at an angle of 45°. Fine and 
coarse sand and fine gravel alternate with each other. Water- 
worn pebbles of shale were found amongst those of foreign ma¬ 
terial. A few of those of the latter material attained the size 
of cobbles of 5 or 6 inches. Till covers the ridge as usual. 
