164 G. F. Wright — Continuity of the Glacial Period. 



direct glaciation, a buried channel- which appeared to be pre- 

 glacial. Of this I wrote a brief account in the March number 

 of the American Geologist for 1893 (pp. 198-199). The 

 accompanying map (Fig. 2) will explain the situation.* 



The buried channel occurs at Homewood, on the Big 

 Beaver, about nine miles from its mouth, and where Clark's 

 Run joins it from the west. The Big Beaver is here walled 

 in by thick and extensive deposits of compact Homewood 

 sandstone which is extensively quarried in the vicinity. The 

 river occupies a gorge in the sandstone whose perpendicular 

 descent from the rock shelf to the surface of the water ponded 

 back by the dam at Beaver Falls is, as measured by lock level, 

 145 feet ; but the rock bottom, as determined in building the 

 railroad bridge at Ellwood Junction, two miles above, is, 

 according to data gathered by Mr. Hice, sixty feet below the 

 bottom of the Beaver. Just how deep the water in the pond 

 is I am unable to say, but probably not more than ten or 

 twelve feet. This will make the present depth of the gorge 

 225 feet. Above Clark's Run this shelf bears a vast amount 

 of sand, gravel, and bowlders derived from the wash of the 

 glaciated region, whose boundary approaches to within two or 

 three miles of the locality. Many sandstone bowlders several 

 feet in diameter occur in this deposit. Clark's Run, which 

 enters the Beaver at right angles, has cut a gorge with a V- 

 shaped mouth through the Homewood sandstone nearly to the 

 level of Beaver Creek. The north side of this wide, deep 

 side channel of Clark's Run is filled in with a water deposit, 

 consisting of stratified sand and gravel, capped by three or 

 four feet of coarser deposits containing large bowlders. This 

 has been resorted to for sand and gravel until great masses 

 have caved down, and obstructed the road which passes along 

 its foot up the run. We were unable to determine just the 

 depth to which this deposit extends ; but it is certainly from 

 sixty to eighty feet deep, and the angle between the gravel 

 pits and the Big Beaver is entirely occupied by it. So com- 

 pletely was this filled in at that point, that it is also difficult to 

 tell just how wide the mouth of the Y-shaped opening was. 

 On the south side of the gorge of Clark's Run the jagged 

 rocks are exposed from top to bottom, although near the 

 mouth there are some remnants of gravel at the top, showing 

 that it had originally filled the whole space. The shelf south 

 of Clark's Run presents a great contrast to that north of the 



* A portion of the valley of Big Beaver Creek above its junction with the 

 Ohio. The broken lines approximately mark the limit of the later Glacial terrace. 

 The space between the broken line and the continuous line outside of it approxi- 

 mately represents the rock shelf bearing the older Glacial gravel. The figures 

 indicate elevations above tide. 



