110 Silicious Slate. — Kenawha Coal Strata. 



size ; a portion of these casts is in my collection. The specific grav- 

 ity of the coal in this bed is 1.25. It contains over sixty per cent 

 of charcoal, as eighteen grains of it decompose one hundred grains 

 of nitrate of potash, when burned in a crucible ; and forty grains leave 

 twenty six of coak, which probably contains considerable earth, as a 

 large portion of cinders is left when burned in a grate. — 4 feet. 



9. Very dark colored, nearly black, silicious slate, or lydian 

 stone, in thin beds, of from two to six or eight inches in thickness. 

 This deposit forms tlie roof of the coal, a thin stratum of shale be- 

 ing interposed . It is five feet " thick at this spot, at others it is six 

 and eight feet. I consider it one of the most remarkable deposits of 

 the whole series. It is extremely hard, not being impressed by the best 

 tempered steel. The aborigines manufactured it into arrow heads, 

 knives, &ic. which are often found in the ploughed fields, throughout 

 the valley. I have traced this deposit from the mouth of Elk river, into 

 the Gauly mountains, a distance of more than forty miles; while its 

 extent, east and west, has been traced from the head waters of Elk, 

 over to the Guyandotte, a still greater distance, covering an area of 

 at least two thousand square miles. While coals and sandstone rocks 

 from different beds so much resemble each other, this has a charac- 

 ter of its own not to be mistaken. As we approach the falls of Ken- 

 awha, this deposit still maintains its elevation above the other strata, 

 and is seen crowning the tops of the hills six or seven hundred feet 

 in height, where the superincumbent sandstone rock had been wasted 

 away. As we approach the dividing ridges between the Gauly, 

 and the small streams putting into the Kenawha, it is seen towards 

 their sources forming falls and cascades in their beds ; its superior den- 

 sity compared with other rock strata preventing its abrasion or dis- 

 intregation. As we travel still nearer the dividing ridges, it disap- 

 pears under the superincumbent sandstone rock, and again crops out 

 on the opposite side of the ridge on coal river; this deposit is seen in 

 similar situations on the heads of Elk, and is found high in the hills 

 near their tops. Whence could have been derived the materials 

 for such an extensive deposit of silicious matter, in a secondary re- 

 gion ? The fact excites our wonder — but doubtless the process, by 

 which it was accomplished, was very easy. Water, at its usual 

 temperature in this climate, will hold in solution but a small amount 

 of silex ; but when at the boiling point or at an elevation much 

 greater, as it is often found in volcanos, under great pressure, it 

 is capable of holding suspended large quantities of silicious matter 



