Var. a. Felspathic steatyte.
b. Pyroxenic.

c. Amphibolic.

Subgroup C. Eklogyte.

D. Epidosyte.

E. Kaolin.

F. Fuller's earth.

G. Meerschaum.

H. Magnesyte.

Group H.-TUFF (Ingenite in part, derivate in part).

Subgroup A. Felstone tuff.

Var. a. Quartzose.

b. Calcareous.

c. Pyritous.
d. Cupriferous.
e. Hematitic.

B. Whinstone, or Basic tuff.
Var. a. Hornblendic.

b. Pyroxenic.

c. Chloritic.

d. Calcareous.
e. Pyritous.

f. Cupriferous.
g. Hematitic.

C. Calcareous tuff.

D. Arenaceous.

E. Argillous.

F. Hematitic.
G. Pyritous.
H. Cupriferous.
I. Steatitic.
J. Porphyritic.

K. Nodular.

Var. a. Concretionary tuff.

b. Spheroidal.

L. Shaly tuff.

Var. a. Flaggy.

b. Slaty.

M. Conglomeritic tuff.

Var. a. Brecciated tuff.

b. Plutonic agglomerate.

Group J.-AUGITIC GROUP.

Subgroup 4. Augyte, or Doleryte.

Var. a. Nephelite augyte.

b. Haüynophyre.

c. Allogovyte.

d. Common augyte.
e. Anamesyte.

f. Basalt.

g. Porphyritic basalt.
h. Amygdaloidal basalt.
i. Basalt lava.

j. Variolitic basalt.

Group K.-VOLCANIC TUFA AND PEPERINO (Ingenite in part,

derivate in part).

Class IV.-TRANSITION OR METAMORPHIC SEDIMENTARY ROCKS.

Group L.-GNEISS.

Subgroup A. Felspathic and felsitic gneiss.

Var. a. Orthoclase gneiss.

b. Oligoclase gneiss.

e. Alpinyte.

d. Adularia gneiss.

B. Micaceous gneiss.

Var. a. Two-mica gneiss.
b. White mica gneiss.
c. Black mica gneiss.

C. Quartzitic gneiss.

D. Basic gneiss.

Var. a. Hornblendic gneiss.
b. Chloritic gneiss.

c. Talcose gneiss.
d. Protogene gneiss.

E. Iolitic gneiss.
F. Hematitic gneiss.

G. Graphitic gneiss.

H. Common gneiss.

Var. a. Compact gneiss.
b. Slate gneiss.

Var. c. Ribaned gneiss.
d. Fibrous gneiss.

Subgroup I. Oblique gneiss.
Var. a. Curled gneiss.
b. Nodular gneiss.

c. Conglomeritic gneiss.

J. Porphyritic gneiss.
K. Granitoid gneiss.

H. Minerals forming rock masses (see page 22).

Var. a. Quartz.

b. Corundum,

c. Apatite.

d. Magnesite.