198 BRIGHAM—TOPOGRAPHY AND DEPOSITS OF MOHAWK VALLEY. 
Frankfort-Ilion drift benches.—A noncommittal term is here used for 
aggregations which may in part have the nature of deltas. The valley 
about Utica is quite free from marginal drift. As indicated by Cham- 
berlin, drift shoulders appear a few miles to the east, becoming strong 
about Frankfort and Ilion. Three miles west of Frankfort a section of 
60 feet, obscured by slip at the base, displays 380 feet of horizontal beds 
of yellowish silt, with blue clayey layers above, still overlain by 10 feet 
of tough unstratified till containing many small scratched pebbles. 
Thence the surface rises by a concave curve to the steep upper hillside 
without any line of. demarkation between the deeper drift of the valley 
and the thin mantle of the higher slopes. This is a common phase of 
_ the valley topography from this point to Little Falls. The valleyward 
edge presents an erosion escarpment gashed by numerous small ravines. 
Kastward the bench fades to a gentle slope, reappearing near Frankfort 
as a considerable feature. It is a mile and a half long and a mile wide, 
having an altitude of 480 feet on the river side and 540 to 560 feet at the 
base of the valley slope on the southwest. The surface is a gently slop- 
ing plane, rather stony. Toward the river, sections of 6 to 8 feet show 
sand, and in one case open grayel inclined toward the valley. Farther 
back coarse gravel with boulders is found, and under this sometimes fine 
clay. Structure and contours suggest the delta, but the stream from the 
southwest is local, and the drift mass lies wholly on one side of it. Pos- 
sibly the mass is related to a yet unstudied channel passing south of 
Frankfort hill, which may have acted asa spillway before the main valley 
was open.* 
A similar terrace lies on the west of Ilion, having the same altitude 
in front, but rising to 600 feet, a mile and a quarter south, in the valley 
of Steeles creek. Near the front a 16-foot excavation penetrated coarse 
gravel above and fine gravel below. Farther south, in a sand pit at the 
upper edge of the terrace, several feet of coarse gravel were found to be 
underlain by 25 feet of fine, horizontally bedded sand. At the 600-foot 
level farther south the section afforded by Mr Warner’s well is— 
Feet 
Se hoo level Bene eri Se Binieia Gin Dio Noes Dee Gor O ech cicre cc 10 
Imes, VMS GEN? s iO JOOS. 50+ ooossc5cbeooog 0 eNK 60 
Giravieli tienen teeter ceeree lees eee ta het ocaioncts Rete Ratit thor il 
71 
A small shoulder appears on the east side of the creek, from the Rem- 
ington residence south toward the cemetery. Here a well was drilled toa 
*See forthcoming Utica atlas:‘sheet, a preliminary proof of which is in hand, through the cour- 
tesy of the U. S. Geological Survey. 
