Section on Yellow Creek. 25 
ona bed of fine micaceous sand, in which is found permanent water 
for wells. Above the blue clay, the water is soft and good for wash- 
ing ; that below is impregnated with an acid, and is hard. 
The following section of rock strata, (fig. 3.) taken on Yellow 
creek, a southern branch of the Mahoning, near Poland, will show 
the order of stratification, including the semi-tertiary deposits, to the 
bed of the stream. Order descending. 
a igi 
$ |e 
42 15 
———— 2 
Bed of the river. 
1. Semi-tertiary deposits, composed of clay, intermixed with 
bowlders of primitive rocks, pebbles and gravel.—15 feet. 
2. Tenacious blue clay, or plastic clay.—6 feet 
3. Fine, white micaceous sand, with pebbles. 5 this bed is found 
permanent water for wells.—2 feet. 
4. Light gray, slaty sandstone rock, with some mica. This deposit 
contains the casts and impressions of many species of fossil plants, 
of the arborescent ferns, Calamites, &c.—15 feet. 
5. Brown shale, filled with kidney-shaped masses of argillaceous 
iron ore, containing blende and oxide of zinc, in small quantities, 
with sulphate of magnesia, on the dry surface of the shale, in fine 
crystals.—1 foot. 
6. A stratum of an apparently crystalline, calcareous fossil, shoot- 
ing into pyramidal masses, closely. compacted ; about four inches in. 
thickness. Specific character,—shajpe, conical ; surface marked % 
numerous undulating, circular striz ; color, light slate ; from two 
Vou. XXXI.—No. 1 4 
