1 68 Bulletin of Laboratories of Denison University voi. xi] 
Four miles to the east another tributary enters the valley 
from the south. Rising near Somerset in Perry county and 
flowing northward through Hopewell township of the same 
county. To the east of this southern tributary several more 
smaller streams flow into Jonathan creek from the north. 
Near the county line between Muskingum and Perry 
county a very much larger tributary enters the valley from the 
south. This stream rises in Clayton township of Perry county, 
flowing northward through a part of Madison township of the 
same county, and enters Jonathan creek a mile and a half west 
of the Muskingum and Perry county line. Its valley is similar 
to and continuous with the valley of Jonathan creek, while just 
to the east the valley of Jonathan creek is very much smaller 
and narrower. From Thornport east Jonathan creek flows in 
an old valley filled up to a great depth with silt. 
From a width of 2 miles at Thornport the valley gradually 
narrows toward the east. At Glenford the valley is about one 
half mile in width. The valley continues to narrow from this 
point on to the east and near the Muskingum and Perry county 
line, the valley is not over 500 feet in width. Passing east from 
Thornport the valley walls loose their gently sloping character 
and assume a more rugged and precipitous form. At Mt. Perry 
the valley is 300 yards wide. A short distance from this place, 
and almost at the county line the valley walls are 150 yards 
apart at flood plain. Soon the valley comes to have the appear- 
ance of a veritable gorge. The gorge extends for 3 miles with 
a width varying from 150 to 500 feet, bounded by rock walls, 
which rise to the height of 200 feet above the flood plain of the 
creek, as is shown on the map of the col. (Plate XXVI.) 
The light continuous lines on Plate XXVI represent 50 foot 
contour lines measured from the flood plain. The heavy black 
wavy line shows the present course of Jonathan creek through the 
gorge ; the broken line indicating its abandoned course, The Co- 
lumbus, Shawnee and Hocking railroad is mapped in as a contin- 
uous line with numerous intersecting short lines. Points heavily 
shaded mark places where rock cuts have been made to allow 
for the railroad and creek beds. 
