34 GYPSUM AND ALABASTER OF ITALY. 
Another specimen (No. 13) is very similar to No. 14, but the layers of sulphate of lime tre 
thicker, and the specimen appears to have been broken ide a different and a large mass. 
'The collection made along the 35th parallel, partly in the valley of the Canadian, contains 
several specimens from this same extensive Gypsum formation, which are peculiar for their 
deep-red color and the well-defined crystalline structure, showing that the color is not due to 
an ordinary mechanical mixture. The greater part of the mineral on the route, especially that 
on the Pecos, appears to be the white granular variety, the same in which the beautiful white 
eaves are found. Captain Pope, however, mentions the selenite as if it existed in large quanti- 
ties also. It would be very interesting to determine whether any portion of these beds are of 
anhydrite, or whether it is found isolated in the strata, apart from the gypsum. The occur- 
rence of large quantities of anhydrite with the gypsum in the Carboniferous strata of Nova 
Seotia renders the inquiry still more interesting, as another mineral character might be added 
to the already numerous points of resemblance. I quote from Mr. Dawson’s book a description 
of a part of the gypsum deposit of Plaister Cove: ‘‘ About two-thirds of the thickness of the 
bed consists of crystalline anhydrite, and the remaining third of very fine-grained common gyp- 
sum. The anhydrite prevails in the lower part of the bed, and common gypsum in the upper; 
but the greater part of the bed consists of an intimate mixture of both substances, the common 
gypsum forming a base in which minute crystals of anhydrite are scattered, and bands in which 
anhydrite prevails, alternating with others in which gypsum predominates. It is traversed by 
veins of compact gypsum, but I saw no red or fibrous veins like those of the marl. In some 
parts of the bed, small rounded fragments of grey limestone are sparingly scattered along layers 
of the gypsum.’’! 
The applications of gypsum in the arts, both in its raw state and prepared, or ground into 
plaster, are multiplied and various. It is an interesting fact, that selenite was well known to 
the ancients, who, according to Pliny, made bee-hives out of it, in order to see the bees at work 
within. According to Dr. Hitchcock, it was used by the wealthy and in palaces for windows, 
under the name of Phengites, and ‘‘ has the curious property of enabling a person within the 
house to see all that passes abroad, while those abroad cannot see what passes within. Hence 
Nero employed it in his palace."? The uses of alabaster are well known. Large quantities 
are worked inte ornamental objects—vases, statuettes, &c.—in the establishments of Florence 
and other places in Europe.’ The fibrous variety, or satin-spar, is sometimes used for making 
ornaments and beads, called Roman pearls. But by far the most important applications of 
gypsum in the arts, are those of plaster of Paris. In this state it is used for moulds, casts, 
statues, as a cement, for plastering walls, and for ornaments on ceilings. The crude, unburnt 
gypsum, when powdered, is largely used in agriculture as a fertilizer. Enormous quantities 
of this substance are thus annually consumed in the United States. It is brought from the 
quarries of Nova Scotia, and finds its way, by rivers, canals, and railroads, to nearly all parts of 
! Acadian Geology, p. 280. ? Marcy's Report, p. 173. 
* The following erpen by W. J. Hamilton, esq., of the gypsum and alabaster mine near Castellina, in Tuscany, is 
interesting in this con 
** We entered the mine gu an inclined bend and, passing under ground, soon reached an open well, or large inverted 
cone, around which the inclined path is carried, and where the section of marls and um is well exposed. As the 
ding road passes through the "vin and — gypsum beds, galleries are seen striking into the rock in all directions. 
The first and second gypsum beds are of a uniform character and grey color, and do not contain any alabaster blocks. 
These are found, principally, in the third Fue fourth beds, and occur as irregular, isolated, spherical masses, imbedded in the 
gypsum, from which they are, mineralogically speaking, distinctly separated by a thin black crust, whisk indicates to the 
workman the existence of the finer nodules. ese nodules are most frequent in the lower part of the stratum, and occur 
regular layers, never touching, although varying much in their distances from each other. In bed number 3 there are 
two layers of these nodules, and in number 4 there are three. They vary much in size, weighing from 20 or 30 pounds 
to upwards of 2,000 pounds. When the workman discovers the black crust, he is at once aware that he is near a block of 
alabaster, ai and, M uv « the direction of the crust, -— removes the gypsum all round until he has nearly detached the 
4 carefully e parent rock. Gunpowder is occasionally used to blast the rock, 
when's black crust indisates the existence of the =e This crust, in connexion with the pure alabaster, is, perhaps, 
