350 



GYPSUM. — MARBLE. 



Valley of the Ohio gypsum is nowhere found ac- 

 companying the rock-strata near the surface of the 

 earth, though indications of it are discovered at 

 great depths, below, especially at the works on the 

 Muskingum River. Gypsum," says Dr. Hildreth, 

 " is deposited in extensive beds on the borders of 

 the valley, in the secondary and transition rock at 

 the surface, and may be deposited beneath the 

 series of sandstone and coal, deep in the earth 

 throughout the whole valley. It is seen in great 

 abundance along the southern shore of Lake Erie, 

 near Sandusky, and in various other intermediate 

 places, quite to the borders of New-York, and in 

 the interior of that state, being found at intervals 

 from the shore of the lake to the mountain ranges. 

 At the salt-works on the heads of the Holstein, 

 it is discovered in great abundance, appearing part- 

 ly to encircle the salt region with a cordon of de- 

 posites." 



Marble. — There are many beautiful and valuable 

 marbles obtained in different parts of the United 

 States. The Latin word marmor^ from which the 

 term marble is derived, was applied by the ancients 

 to all stone susceptible of a fine polish, but at pres- 

 ent the word is confined to such varieties of carbon- 

 ate of lime as are susceptible of polish. Both gran- 

 ular and compact limestone furnish numerous vari- 

 eties of marble, but those which belong to Ihe former 

 exhibit a more uniform colour, a greater translu- 

 cence, and are generally susceptible of a higher 

 polish, and, therefore, are most esteemed for statu- 

 ary and other purposes. 



The uniformity of colour so common in primitive 

 marble, is sometimes interrupted by spots, or veins, 

 or clouds of different colours, arising from the in- 

 termixture of hornblende, serpentine, talc, chro- 

 mate of iron, &c. 



Vermont and the western part of Massachusetts 

 abound in white and gray marbles of great excel- 



