Association of American Geologists and Naturalists. 223 
quarry and gravel pit—every tunnel through a mountain, and 
every pit and gallery of a mine—every boring for coal, for salt, 
or salt water, and every artesian perforation—furnish means of 
perusing the interior structure. Still more, do the inland preci- 
pices and the rocky promontories and headlands that rise along 
the rivers, lakes, seas and oceans; the naked mountain sides, 
ribbed with jutting strata, that banal the defiles, gorges, and 
valleys ; the ruins accumulated at the feet of lofty pinnacles and 
mountain barriers, and those that have been transported far and 
wide over the earth, present to us aerhlalagy features of the interior 
structure of the planet. 
“Most of all, do the inclined strata push up their hard edges 
in varied succession, and thus faithfully disclose the form and 
substance of the deep interior, as it exists—many, it may be 
hundreds of miles and leagues, beneath the observer’s feet.” 
“Volcanic eruptions throw up into daylight, the foundations 
of the fathomless deep below, either in the form of ejected or of 
molten masses, flowing even in rivers of fluid and ignited rocks, 
which congeal again on the surface of the ground, either inflated 
like the scorie of furnaces or in solid forms; often retaining no 
visible impress of fire, and containing, occasionally, very perfect 
and beautiful minerals, produced by heat in the bosom of the 
Felcano, or ~~ from: still earlier; beds from. amon profound 
t which 
often ruptures. sane crust of the earth, and covers it with a fiery 
deluge.” , as, AQT 
“In addition: to the sebdticte: 06. wie wolcantes-«dhe. ignige- 
hous rocks, the granites, the sienites, the empetenenten the serpen- 
tines, the soapstones, and the traps- 
dasiieted from fusion—injected both i in the earlier and in many 
of the more modern epochs, among other rocks, and cutting across 
the strata of almost all descriptions and ages, are thus assimilated 
to the lavas, the known products of internal heat. Thus they 
give authentic information of the unapproachable ’ gulf of fire, 
from which they were projected.” 
The internal waters that gush cool from the fountains on land 
or under the sea, or those jets that spout in boiling geysers, from 
the deep caverns, where their imprisoned vapors accumulate ex- 
plosive force ; all these bring to the surface the materials of the 
deep interior, and conspire with tornadoes of gas, bursting from 
