BROADWAY MORAINE. 541 



[Prospect], which is on the Scioto, in Marion Count}^ and passing about a mile to the 

 west of Delhi. It is traceable nearly to Millville. It is intersected by the gravel 

 road about a mile north of Delhi. The road then follows it to Middletown, where 

 it becomes lost from further observation. This interesting series of ridges is not 

 arranged in a single continuous line, but the sepai-ate ridges overlap each other, rising 

 and falling at irregular intervals. Sometimes the line appears double; low places on 

 one side are in some places made up by full deposits on the other. On either side the 

 country is flat, the soil is of close clay, and the roads very muddy in rainj^ weather. 

 The Delhi beds of the Lower Corniferous are exposed at a number of places in close 

 proximity to these gravel knolls, proving the strike of the formation to be exactl}' 

 coincident with this strip of gravelljr land. Toward the east is the enduring Cornif- 

 erous; toward the west, the easih^ disrupted Waterlime. There is a general but 

 verjr gentle slope to the west. The material in these ridges is stratilied sand and 

 gravel, which has been considerabty used in constructing the gravel roads that inter- 

 sect that part of the county. One of these sand and gravel deposits is open for such 

 purposes on the land of Mrs. Rachael Fleming, on the east side of the Scioto, near 

 the mouth of Bogg's Creek, and shows the following alternation of parts: (1) Soil and 

 hard pan, 2 feet; (2) gravel and sand, stratitication confused or wanting; (3) hand- 

 some strata of sand oblic^uely stratified. 



The outward appearance and composition of this series of gravel ridges are the 

 same as of those ridges well known in the country as "hogs'-backs," yet they are less 

 prominent than some others that have been described in northwestern Ohio. (See 

 report on the geology of Hardin County, also report on geolog}' of Allen County.) 

 Their long continuance and their more uniform height make them in some respects 

 comparable to those ver}' long gravel ridges that have been described in northwestern 

 Ohio, and referred to the efl'ect of glaciers, crossing a number of counties consecu- 

 tively. Their real origin, however, is not that of terminal glacier moi'aines. but is 

 the same as of those isolated gravel knolls known as ''hogs'-backs." Similar lines of 

 gravelly rolling land following and marking the boundar3^ between two geological 

 formations have been mentioned in reports on the geology of Crawford and Morrow 

 counties. Such boundary lines, when between two formations of unequal endurance 

 under the glacier, would be the place where most frequentlj^ deep fissures in the ice 

 would be produced by the efforts of the great sheet to adapt itself to the unevenness 

 of its bed. In such fissures and along such openings running water wovild appear, 

 and would most eifectuallj'^ carry away the transportable clayey portions of the drift 

 with which it might come in contact. During the pi-evalence of the ice, such washed 

 and perhaps stratified drift would be liable to a further transportation; but when the 

 margin of the glacier finally passed northward over any point on such boundary 

 line, the final effect of the water issuing from the ice at that point would be left 

 undisturbed, and would be preserved to the present time. The obliqueness of the 

 stratification and the sudden changes in the kind and arrangement of material 

 making up the strata, together with an occasional mass of unassorted glacier clay 

 included in the stratified portions, not onlj' indicate the force and direction of the 

 torrents of water and an interrupted supply of drift, but also the presence and agenc}' 

 of thick glacier ice at the time of deposition. 



