238 GEOLOGY OF ILLINOIS. 



mainly derived from the Niagara limestone. A limestone reported six 

 miles south and one mile west of Forest, is probably the continuation 

 of the low ridge near Fairbury above referred to. 



At Chats worth two borings three-quarters of a mile apart show much 

 difference in thickness of drift. Iu the S. E. qr. of sec. 4 it is eighty- 

 four or eighty-eight feet, which includes an old vegetable dirt bed. In 

 the S. E. qr. of sec. 3 the drift is two hundred and twenty one feet 

 according to the record of the boring at the sugar works ; and iu this, 

 water was struck at a depth of fifty-two feet iu gravel ; again, at seventy- 

 five feet in quick-sand ; a third vein at one hundred and nine feet in 

 sand and gravel. The water of these three veins rose to within twenty- 

 seven feet of the surface. A fourth vein in gravel at two hundred and 

 ten feet rose to within twentv-five feet of the surface. 



Goal Measures. 



The Big Vermilion river, from the north line of the county to Pontiac, 

 affords many exposures that help to determine the changes in the Coal 

 Measures. 



A coal bank on the S. W. qr. of the S. E. qr. of sec. 1, T. 30 N., E. 3 

 E., shows the Streator coal, which is here divided by a clay seam fifteen 

 inches thick, leaving thirty-three inches of coal above and twelve inches 

 of coal below it. The coal here is a little below the bed of the river, 

 and a quarter of a mile below, it is at the river level. A quarter of a 

 mile above the mine the coal at Newtown mill is in the bed of the river 

 below the dam. A half mile below the mine the clay parting is only 

 one-eighth of an inch thick. 



Glen wood mill is on the N. E. qr. of sec. 12, about the middle of the 

 quarter section. The river runs north 35° west, and the sandstone 

 above the shale that overlies the coal at Streator, shows here with a dip 

 south 35° east, one foot in ten. At the mill the dam rests upon the coal. 



One mile above the dam the coal appears again. It was worked in 

 1800 and 1SC1, and said to be three and a half feet thick. 



One hundred and twenty rods north of the south line of sec. 18, T. 30 

 N., E. 4 E., the coal is four and a half feet thick on the east side of the 

 river. At the south line of sec. 18 the coal is under the river not more 

 than eight feet. Farther down the river a short distance, on the west 

 side, the coal is three feet thick. 



At the north-west corner of the S. E. qr. of the N. W. qr. of sec. 19, 

 T. 30, E. 4 E., a limestone nearly six feet thick appears where the river 

 makes a bend west. This rests on a blue clay, and appears to be No. 



