384 =A. A. Hayes on Serpentine Rock of Roxbury, Vt. 
conclusion that a hydrate of magnesia forms a part of the com- 
position of all such rocks. 
Il. ‘The following results. embrace the averages on compact, 
nearly white portious : 
Moisture, . : : j ; : : 0-08 
Water from hydrated minerals, : é . 0-98 
Carbonic acid, 47°16 
Magnesia, : ; ; 2 : : 44:24 
Tale laminz and trace of Silicic acid, - ; 5-20 
Silicate of alumina, ‘ A R ‘ . 0-64 
Protoxyd of iron from Sil. iron with manganese, 1:53 
99 83 
showing the influence of a small admixture of the included 
minerals. 
IIL. In the following results, the average of the whole rock as 
quarried is given, the dark greenish plack, light green, and white 
colors, intermixed — 
100 parts divide into 
Moisture, . ; 7 in ; - ; 0:40 
Carbonate of magnesia, . : : : . 38:00 
Included minerals, . : ; : ; 61-60 
100: 
61-60 of the various minerals forming the base of the compound 
rock, consisted of— 
Combined water, Bee og oe 6:44 
Silicic acid, . ; : gh oe : . 36°92 
Magnesia, . “ = ; ; : ; 10°52 
Protoxyd manganese and proto-peroxyd of iron, 4°80 
Alumina, : ; : : : ~ 2-06 
Chrome iron, - i : j . - 0-63 : 
61:37 
The basis rock, thus proved to be the hydrated ingredient, 1s an 
indefinite mixture of so-called serpentine. It is however easily, 
resolved into greenish-white talc, asbestus in various forms, rarely 
actinolite, ordinary slate as silicate of alumina and iron, consll- 
tuting an aggregate. But the most remarkable fact is, the entire 
absence of the compounds of lime. ; . 
In view of this chemical composition and its physical charac- 
ters, I propose that this rock quarried for ornamental purposes, 
be hereafter called serpentine marble. 
Some early analyses of mine had shown the presence of car- 
bonate of magnesia in the serpentines of Troy and Mt. Holly in 
Vermont, which also are aggregates of magnesian rocks, oo 
some argillite. ‘To represent more accurately the relations 
