Section on Yellow CreeJc. 



25 



on a 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. 



Fiff. 3. 



feet, 44 S^^^;S^^S^^^^^^^^^^ ^^^ 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. In 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, Sec. — 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, — shape, conical ; surface marked by 

 numerous undulating, circular strias ; color, light slate y from two to 



Vol. XXXL— No. 1. 4 



