James F. (James Furman) Kemp.

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feldspar and quartz. The name is derived from the Unaka range of
mountains along the border of North Carolina and Tennessee, and was
first given by F. H. Bradley in 1874. (Amer. Jour. Sci., May, 1874,
519.) Other localities have since been noted. (See T. L. Watson,
Idem, Sept., 1906, 248.)

Uralite, a special name for that variety of hornblende, that is derived
by paramorphism from augite. The word is often used as a prefix be-
fore the names of those rocks that contain the mineral. It has also
suggested various rock names, such as proterobase, scyelite, etc. The
name is derived from the original occurrence in the Urals. (G. Rose,
Reise nach dem Ural, II., 1842, 371.)

Urtite, a name given by W. Ramsay to a light colored rock of medium
grain, consisting of nephelite in largest part, with which is consider-
able aegirite and a little apatite. When recast an analysis gave ne-
phelite, 82; aegirite, 16; apatite, 2. The name is derived from the
second part of Lujavr-Urt, the name of the mountain where it occurs in
northern Finland. Geol. Foren. Forh., XVIII., 463, 1896.

V

Valbellite, a name derived from the Valbella valley of Piedmont,
and applied by R. W. Schafer to a dike of amphibole-peridotite, con-
sisting of olivine, brown hornblende, bronzite, pyrrhotite, spinel and
magnetite. (Cited by H. Rosenbusch, Mikros. Phys., 4th ed., II., 462.)

Variolite, a special name for a curious, border development of dia-
base intrusions, which is a very dense, finely crystalline mass of rounded
spheroids, largely spherulitic in texture. They give the rock a pock-
marked aspect and hence the name, which is a very old one. Pearl
diabase is synonymous.

Vaugn6rite, a name derived from Vaugneray near Lyons, and applied
by Fournet in 1836 to a dike-rock, which is now shown by Michel-Levy
and Lacroix to be an amphibole-granite. They advise dropping the
special name. (Bull. Soc. mineral de France, 1887, X., 27.)

Vein, strictly speaking, the mineral matter which has been deposited
in fissures in rocks from solution. Water, assisted by dissolved sub-



GLOSSARY. 263

stances, is the almost invariable solvent. The name was doubtless
originally given because of the similarity of the ramifying and often
intersecting deposits, to the veinsof man and animals. Vein is contrasted
with dike, which chills in a fissure from a fused condition. While the
above simple statement holds true for the vast majority of cases there
has yet arisen a need of expansion. We find associated with many
veins, impregnation and oftentimes replacement of the walls, such that
the original supply fissure is a relatively small part of the resulting
deposit. We find again, veins, such as the apatite deposits of Norway,
obviously formed in large part at least by vapors and gases emitted in
the cooling stages of igneous rocks, in the processes called pneumatolitic.
Volatilization may largely operate instead of mere solution; and re-
placement of the wall rocks may be extensive. Again in the formation
of pegmatites we believe that the process is intermediate between solu-
tion at exalted temperatures and pressures; and fusion in the presence
of abundant water vapor or dissociated hydrogen and oxygen, and
other mineralizers. Some geologists describe pegmatites as dikes;
some as veins. The point may also be made that since all igneous
magmas are regarded as solutions, whose dissolved matters crystallize
in the inverse order of their solubilities, no distinction can be drawn be-
tween veins and dikes. But at least in dikes almost the entire solvent
solidifies with the dissolved matter, whereas in typical Veins the solvent,
water, passes on after precipitating its burden.

Ore-deposits occur so often in veins, as strictly defined above, that
the prospector and miner have applied the name vein to any and every
form of ore-body. The coal-miner even speaks of coal-seams as veins,
although this usage is not to be commended in carefully chosen scientific
language.

Venanzite, a name proposed by Sabatini, an Italian petrographer,
for an effusive rock from a small volcanic cone at San Venanzo, Um-
bria, Italy. Venanzite contains phenocrysts of olivine in a groundmass
of melilite, leucite and black mica, together with a little pyroxene,
nephelite and magnetite. Bolletino Reale Comitato Geologico, Sept.,
1898. Rosenbusch subsequently described the same rock under the
name Euktolite, but Venanzite has priority. Sitzungsber. k. pr. Akad.
Wissensch. Berlin, VII., no, 1899; Amer. Jour. Sci., May, 1899, 399.

Verite, a name derived from the Spanish locality Vera, near Cabo de
Gata, and given by Osann to a post-Pliocene glassy rock, with pheno-
crysts of biotite and microscopic crystals of olivine and augite and some-
times plagioclase, all of which seldom form half the mass of the rock.
It is a glassy variety of the mica-andesites with exceptional olivine. Z.
d. d. g. G., XLI., 311, 1889. Compare Fortunite.



264 A HAND BOOK OF ROCKS.

Vintlite, a quartz-porphyrite occurring in dikes near Unter-Vintl, in
the Tyrol. Compare toellite from the same region. Pichler, Neues
Jahrb., 1871, 262.

Viridite, a microscopic name suggested by Vogelsang and formerly
used for the small, green, chlorite scales often met in thin sections.
As their true nature has now been determined, they are generally called
chlorite.

Vitro, a prefix meaning glassy and used before many rock names, as
vitrophyre, in order to indicate a glassy textur .

Vitrophyre, Vogelsang's name for quartz-porphyries and porphyries
with glassy groundmass.

Vogesite, Rosenbusch's name for syenitic dikes, in which the dark
hornblendes or augites are in excess over the light colored feldspars.
Mass. Gest., 1887, 319. The name is derived from Vogesen, the Ger-
man form of Vosges.

Volcanic, surface flows of lava as distinguished from plutonic rocks,
see p. 1 6.

Volcanite, a name proposed by W. H. Hobbs, for an anorthoclase-
augite lava with the chemical composition of dacite. Bull. Geol. Soc.
Amen, V., 598. The name was suggested by the original occurrence
on the island of Volcano, one of the Lipari group, where the rock is
met as cellular bombs.

Volhynite, a p^rphyrite containing plagioclase, hornblende and bio-
tite phenocrysts in a holocrystalline groundmass of feldspar and chlorite.
The name was given by Ossovsky, and it is based on the original occur-
rence in Volhynia. See Chrustschoff, Bull. Soc. Min. France, 1885,
441.

Vulsinite, a name suggested by H. S. Washington for a group of rocks
intermediate between trachytes and andesites. They contain much
labradorite in addition to the usual minerals of trachyte. The name
is derived from the Vulsinii, an ancient Etruscan tribe inhabiting the
region where the type specimens were obtained. Journal of Geology,
IV., 547. Compare latite and trachydolerite.

W

Wacke, an old name for the surficial, clayey products of the alteration
of basalt. The syllables are still current in graywacke.

Wash, a miner's term in the West for loose, surface deposits of sand,
gravel, boulders, etc.

Websterite, a name proposed by G. H. Williams for the pyroxenites
near Webster, N. C., that consist of diopside and bronzite, with the



.GLOSSARY. 265

latter porphyritically developed. Amer. Geol., VI., 35, 1890. The
name websterite had been previously used by A. Brongniart in 1822 for
aluminite. Hauy's Mineralogie, II., 125.

Wehrlite, a name originally suggested by von Kobell for what was
supposed to be a simple mineral, but which proved to be a peridotite
consisting of olivine and diallage.

Weiselbergite, Rosenbusch's name for those augite-porphyrites whose
groundmass consists of a second and sometimes third generation of
plagioclase rods and augites, arranged in flow lines in a glassy basis.
Mass. Gest., 501, 1887. Wadsworth uses the name for an altered
andesite glass. Kept, of State Geol. of Mich., 1891-92, p. 97..

Whinstone, a Scotch name for basaltic rocks.

Wichtisite, a glassy phase of diabase, named from a Finland locality,
Wichtis. Compare sordavalite.

Windsorite, a name derived from Windsor, Vt., and applied by R.
A. Daly to a dike rock " leucocratic, hypidiomorphic-granular, com-
posed essentially of alkaline feldspar (microperthite and orthoclase),
basic oligoclase, quartz and biotite, and characterized by high alkalies
(potash slightly in excess of soda), relatively low lime (contained
essentially in the plagioclase), low iron and low magnesia." (Bull. 209,
U. S. Geol. Survey, 48, 1903.)

Wyomingite, a name suggested by Whitman Cross, for the variety of
rock from the Leucite Hills, Wyoming, which consists almost entirely
of leucite and phlogopite. Small, acicular crystals of diopside are very
subordinate, and apatite is also present. Amer. Jour. Sci., Aug., 1897,
1 20. This is the rock described by Zirkel in 1876 and was the first
known occurrence of leucite in America. Fortieth Parallel Survey,
VI., 259-

X

Xenogenites, Posepny's term for mineral deposits of later origin than
the wall rock. The name means foreigners, and refers to their later
introduction. Compare idiogenites. Trans. Amer. Inst. Min. Eng.,
XXIII., 205, 1893.

Xenolith, a term proposed by W. J. Sollas, for included masses of
rock, caught up in an igneous intrusion. The term means foreign rock.
Xenoliths have been subdivided by Alfred Harker into accidental,
or bodies foreign to the enclosing magma; and cognate, or bodies con-
trasted with the normal magma but derived from it in earlier stages.
In illustration of the latter we may cite glomeroporphyritic aggregates,
basic segregations, orbicular or spheroidal granites, and the olivine-
knollen of the basalts. Cognate xenoliths of single individual crystals



266 A HAND BOOK OF ROCKS.

may be called xenocrystals, such as the occasional quartz in basalt.
Nat. Hist. Ig. Rocks, 346.

Xenomorphic, Rohrbach's textural name for those minerals in an
igneous rock whose boundaries are determined by their neighbors. Its
antithesis is automorphic, which see. Xenomorphic is synonymous
with allotriomorphic, over which it has priority. Tsch. Mitt., 1886, 18.

Yamaskite, a name derived from Mt. Yamaska, Prov. Quebec, and
applied by G. A. Young to a very basic igneous rock of granitoid texture
and consisting of pink, pleochroic pyroxene, basaltic brown hornblende,
anorthite and ilmenite. It has less than 40 per cent, silica and is
chemically near iacupirangite. (Ann. Rep. Geol. Surv. Canada, 17:
Part II., 1907.)

Y

Yentnite, a name derived from the Yentna River, Alaska, and sug-
gested by J. E. Spurr for certain granitoid rocks, consisting of oligoclase,
scapolite and biotite, with a few zircons. The scapolite is believed to
be an original mineral. Amer. Jour. Sci., Oct., 1900, 310.

Yogoite, a name suggested by Weed and Pirsson from Yogo peak, one
of the Little Belt Mountains, Mont., for a syenitic rock composed of
orthoclase and augite in about equal amounts. See also sanidinite and
shonkinite. Amer. Jour. Sci., Dec., 1895, 473-479.

Yte, a substitute for ite, proposed by J. D. Dana, so that by using it
in rock-names they would be at once distinguished from mineral names,
otherwise, in some instances the same.

z

Zircon-syenite, a name originally given by Hausmann to certain Nor-
wegian nephelite-syenites which were rich in zircons. Later it was
practically used as a synonym of nephelite-syenite, but is now obsolete.

Zirk elite, a name proposed by Wadsworth in 1887 to designate
altered, basaltic glasses, in distinction from their unaltered or tachylitic
state. Geol. Surv. Minn. Bull., 2, 1887, p. 30.

Zobtenite, Roth's name for metamorphic rocks with the composition
of gabbros, i. e., rocks not certainly igneous. The name is derived from
the Zobtenberg, a Silesian mountain. Sitz. Berl. Akad., 1887, 611.

Zonal-structure, a term especially used in microscopic work to de-
scribe those minerals whose cross-sections show their successive, con-
centric layers of growth.

Zwitter, a Saxon miner's term for a variety of greisen. Only of
significance in connection with tin ores.



INDEX.



NOTE. The index only concerns the main portion of the book and not the Glos-
sary. Attention may be called to the latter as embracing many rocks not otherwise
mentioned.

A.

Accessory minerals, 12
Acmite in trachyte, 43
Acmite-trachyte, 43
Actinolite, 9
Actinolitic slate, 117
^Egirite, 9
Alabaster, 115

Alumina, molecular ratios, 170
Amphibole-andesite, 63
Amphiboles, 7
Amphibolites, 139-141
Analyses of rocks, 19
Andalusite, 126
Andesine, 6

Andesite-porphyries, 62
Andesites, 60

analyses, 60

description, 61

varieties, 62

synonyms and relatives, 62

alteration and metamorphism, 63

andesitic tuffs, 63
Anhydrite, n
Anogene, 15
Anorthite, 5
Anorthoclase, 5
Anorthosites, 80
Anthophyllite, 8



Anthracite, 112-113

Apachite, 49

Apatite, 12

Aplite, 34

Apobsidian, 27

Aporhyolites, 31

Aqueous and Eolian rocks. Introduction,

92

Arendal, Norway, 109
Arfvedsonite, 8, 9
Argillaceous limestone, 108
Arkose, 98
Atmospheric weathering, defined, 121, 122

rocks produced by, 154-157
Augen in gneisses, 132
Augite, 8, 9

defined, 9
Augite-andesite, 63

-porphyrites, 72
Augitites, 73
Aureole, 124
Auvergne, trachytes, 43-44

267



Bar theory, 114
Baryta, molecular ratios, 175
Basalt-porphyries, 71
Basalts, 69

alteration and metamorphism, 74

analyses, 69

basalt tuffs, 75

description, 70

distribution, 75

synonyms and relatives, 72

varieties, 71
Basanite, 72
Batholiths, 15
Becke, F., cited, 159
Becker, G. F., cited, 146, 153, 155
Beemerville, N. J., 127

nephelite syenite, 50
Biella, syenite, analysis, 44
Binary granite, 35
Biotite, 10
Bituminous coal, 112-113

shales, 101

Blackband iron ore, 112, 118
Black Hills, S. D.. phonolites, 50

trachyte, 43
Bosses, 15
Bostonite, 43

Brazil, weathered rocks of, 154
Breccias, 93, 126

eruptive breccias, 93

friction breccias, 93

talus breccias, 93
Broegger, W. C.. cited, 162
Bronzite, 9
Bytownite, 6



Calcareous sandstones and marls, 103

analysis, 103

metamorphism of, 104

mineralogical composition, 103

occurrence, 104

varieties, 103
-alcarenites, 107
Calcareous shales, 107
Calcilutites, 108
Calcirudites, 107
Calcite, n
Calc-schist. 139
mptonite, 66
Cancrinite, 53



268



INDEX.



Carbonaceous sediments, 112
Carbonates, rock-forming, n
Carbonic acid, molecular ratios, 173
Cement-rock, 109
Chalcedony, 109, no
Chemical analysis, calculations from, ig
recasting, 161

composition, diagrams of, 20
influence of, 17

elements important in rocks, 3
Chert, 109-111, 116-118.
Cherty-iron carbonates, 116-118.

limestone, 108
Chiastolite, 126
Chlorides, mineral, 12
Chlorine, molecular ratios, 174
Chlorite, n

schist, 141-143
Christiania, Norway, 128

syenites, 46

Chromic oxide, molecular ratios, 175
Chromite, n
Citric acid, 119
Clarke, F. W., cited, 3
Classification scheme, igneous rocks, 22,
23

of rocks, principles of. 12
Clay, analysis, 100

description, 102

iron stone, 112, 118
Cobalt oxide, molecular ratios, 175
Conanicut, R. I., 125

minette, 46
Conglomerates, 126
Consanguinity, 91
Contact metamorphism, 121-124

external effects, 122

internal effects, 121

zones, 122

Coral limestone, 107
Corniferous limestone, Ij8
Cornwall, Pa., 129
Cortlandt series, quartz-diorite, 60

series, contacts, 128
Crawford Notch, N. H., 127
Crinoidal limestone, 109
Cripple Creek, Col., phonolites, 50
Cross, Whitman, cited, 170
Crugers, N. Y., 126
Gratification, 114
Crystalline limestone, 148-150

schists, 137

Crystallization, order of, 20, 21
Cupric oxide, molecular ratios, 165
Custer Co., Col., syenite. 46

trachyte, 43
Cyanite, n
Cycle of deposition. 95



Dacite-porphyry, S7
Dacites, 56-58



Dana, J. D., cited, 139
Degeneration of rocks, 155
Derby, O. A., cited, 154
Diabases, 76

analyses, 76

texture of, 77
Diallage, 9

Diatomaceous earth, 109, ill
Dikes, 15
Diopside, 9
Diorite-porphyries, 62
Diorites, 64

alteration and metamorphism, 66

analyses, 64

distribution, 66

mineralogical composition, 65

varieties, 66
Dissolved vapors, 18
Ditroite, 52
Dolerite, 71
Dolomite, n, 108

crystalline, 148-150
Drachenfcls-trachyte, 44
Dunkirk, Md., in
Dykes, see dikes
Dynamic metamorphism, 132



Earth, composition of the crust, 3
Eclogite, 142, 143
Effusive rocks, 16
Eleolite. see nephelite

syenite, see nephelite syenite
Enstatite, 9
Eolian sands, 95
Epidote, n

schist, 142, 143
Essential minerals, 12
External contact metamorphism, 126
Extrusive rocks, 16



Feldspars, 5

Feldspathoids, 6

Felsite, 30

Felsitic texture, 17

Ferric oxide, molecular ratios, 170

Ferromagnesian silicates, 4

Ferrous oxide, molecular ratios, 171

Ferruginous organic rocks, 112

Flexible sandstone, 144

Flint, 117

Fluorine, molecular ratios, 174

Foyaite, 52

Franklin Furnace, N. J., 109

Freiberg minettes, 46

gneisses, 136

Freshwater limestone, analyses, 105
Friction breccia, 91
Fusibility of magmas, 17
Fusing points of minerals, 21
of rocks, 22



INDEX.



269



Gabbro. 78

alterations and metamorphism, 84

analyses, 78

distribution, 84

mineralogical composition, 80

varieties, 80
Gabbro-porphyries, 71
Garnet, n

Generations of minerals, 21
Geyserite, no, in, 116-118
Gieseckite-porphyry, 49
Glasses, 25

analyses, 25

distribution of, 27

geological occurrence, 27

relationships, 27

varieties, 26
Glassy texture, 16
Glauconite, 103
Glaucophane schist, 142, 143
Gneisses, 133-136
Gordon, C. H., cited, 133
Grabau, A. W., cited on limestones.

107

Granite-porphyries, 31
Granites, 33

analysis of, 33

distribution, 38

metamorphism of, 37

mineralogy of, 34, 35

occurrence, 36

relationships, 36

uses of, 37

varieties, 34
Granitoid texture, 17
Grano-diorites; 36

diorite, 59, 60
Granulite, 136, 137
Graphic granite, 35
Graphite, 12
Graphite schist, 143
Gravels and conglomerates, 96

metamorphism of, 96

occurrence, 96
Greensands, 104
Green schists, 142
Greisen, 130
Groundmass, 17
Grorudite, 32
Grflnerite, 118
Gypsum, n, 114, 115



Halite, 12

Harker, Alfred, cited, 124
Hawes. G. W., cited, 127
Hematite, n

Highwood Mtns., Mont., SO
Hillebrand. W. F., 153
Hoboken, N. J.. 127
Hollick. A., cited, 128



Hornblende, 8, 9
Hornblende-schists, 139-141
Hornblendite, 83
Hornfels, 126, 127
Hornstone, 117
Hyalomelane, 26
Hydraulic limestone. 108
Hydromica-schist, 139
Hypersthene, 9
Hypersthene-andesite, 63
fels, 80

I

Iddings. J. P., cited, 170
Igneous rocks, 15

review of, 88

determination of, 90

field observations, 91

mineralogy of, 89

range of composition, 88

typical textures, 89

table of, 23
Ilmenite, n

Infusorial earth, 109-111
Internal contact metamorphism, 124
Intratelluric, 18

Iron Mtn., Mo., trachyte-porphyry, 43
Itacolumite, 144

K

Kaolinite. ir
anals., 92
Kemp, J. F., cited, 127, 128
Keratophyre. 43, 58
Kersanite, 66
Kimberlite. 83
Knotty schists, 127

slates, 127
Kulaites, 72

Labradorite, 6
Labradorite-rock, 80
Laccoliths, 15

Lake Champlain trachyte, 43
Laterite, 154
Latite, 43

Laurdalite. anals., 51
Leucite, 6
Leucite-basalt, 72
Leucite-basanite, 72
Leucite Hills, Wyo., 50
Leucite-phonolitc, anals., Rieden; Ger-
many. 46

defined, 50
Leucite rocks, 50

syenite anals.. 51

tephrite, 72
Leucitophyre, 50
Liebenerite-porphyry, 49
Lignite, 112, 113
Limburgites, 73
Lime, molecular ratios, 172
Limestone, crystalline, 148-150

alteration. 150



270



INDEX.



Limestone, composition, 148

occurrence, 150

varieties, 149
Limestones, 105

analyses, 105

at igneous contacts, 128

origin of, 106
Limonite, II
Liparite, defined, 31
Litchfieldite, anals., 51

defined, 52

Lithia, molecular ratios, 175
Lithographic limestone, 109
Lithophysae, 27
Living organisms, analyses of calcareous

parts, 105

Local metamorphism, 121
Loess. 99
Luxullianite, 35
Lyell, Charles, 121

M

Magnesia, molecular ratios, 161

Magnet Cove, Ark., nephelite-syenite, 50

Magnetite, n

Magnesian limestone, 108

Malacolite, 9

Manganous oxide, molecular ratios, 175

Marble, see crystalline limestone

Marls, analyses, 103

Matthew, W. D., cited. 128

Mechanical sediments, 90

Melaphyre, 72

Melilite. 7

basalt, 74

Merrill, G. P., cited, 155
Metamorphic rocks, determination of,

157. 158
Metamorphism, 121

of limestones, 109
Meteorites, 85
Miarolitic, 17
Mica-andesite, 63
Micas, 9

Mica-schists, 137, 139
Mica-syenites, 45
Microcline, 5
Micro-granites, 36
Mineralizers, 17, 1 8
Minerals, accessory, 12

essential, 12

primary, 12

secondary, 12
Minette, 45

Minor schists, 141-143
Mixed zone, 119
Molecular proportions, 162

ratios, 162

Molecular volumes, 159
Molten magmas, nature of, 20
Monzonites, 45
Mt. Willard, N. H., 127



Muscovite, 10

Necks, defined, 15
Nephelite, 6

Nephelite-basalt, anals., 72
Nephelite-syenite, analyses, 51

description, 51-53

porphyry, 49
Nevadite, 31

Nickel oxide, molecular ratios, 175
Norite, 80

Novaculite, analysis, 97
defined, 98

o

Obsidian, 26

cliff, cited, 27
Ochsenius, cited, 114
Oligoclase, 5
Olivine, 10

Olivine-free 6asalts, 72
Onyx marble, 114
Ophicalcites, 150-153

alteration, 153

composition, 150

distribution, 153

varieties, 152
Ophiolite, see ophicalcite
Oolitic limestones, 108
Orbicular granite, 36
Orendite, 50

Organic remains not limestone, 109
Orthoclase, 5

Dxides, common in rocks, n
Oxygen quotient, 161, 162



Paisanite, 32
Pantellerite, 43, 58
Paramorphism, 75
Peat, 112-113
Pegmatite, 35
Pele's hair, anals., 14
Peridotites, 81
Perlite, 26

Petrographic provinces, 91
Petrosilex, 119
Petite Anse, La., 115
Phanerocryst, 17
Phenocrysts, 17
Phlogopite, 10

'honolite-obsidian, anals., 25
?honolite-porphyry, 49

honolites, analyses, 46
description, 47-51

hosphates, minerals, 12

hosphoric pentoxidc, molecular ratios,
174

hthanites, 102

hyllite, 139

J ilot Knob, Mo., trachyte-porphyry, 43
'irsson, L. V., cited, 127, 163, 170
Pisolitic limestone, 108



INDEX.



271



Pitchstone, 26

Plagioclase feldspars, 5

Plauenscher Grund syenite, 45

Plutonic rocks, 16

Popes Mills, Md., in

Porphyrite, 63

Porphyritic texture, 16

Porphyry, a pre-tertiary trachyte, 43

Potash molecular ratios, 173

Precipitates from solution, 113

Predazzo, Tyrol, 128

Pressure, influence of, 18

Primary minerals, 12

Principles of rock classification, 12

Propylite, 63

Pumice, 26

Pyrite, 12

Pyroxenes, 7

Pyroxenites, 81

Pyrrhotite, 12

Q

Quartz, n

basalt, 73
Quartz-diorite, 59

porphyry, 54, 58
Quartzites, 144-145
Quartz-keratophyres, 32

pantellerites, 31

porphyries, 31

porphyrite, 54

trachyte, 31

R

Rate of cooling, influence of, 18
Regional metamorphism, 121-122
Regionally metamorphosed rocks, 131-

133

Residual magma, 21
Rhyolite granite series, 28

porphyries, 31
Rhyolites, 28

alteration of, 32

analyses of, 28

distribution, 32

general description, 30

relationships, 32

synonyms, 31
Rhyolite, alteration, 32

composition, 28-30

distribution, 32

varieties, 31
Rhyolite tuffs, 33
Richmond, Va., Ill
Rieden, Germany, leucite rocks, 50
Rock, definition of, I

magmas. 17

salt, 12, 114-115
Rocks, chemical composition of, 3

physical range of, 2

principles of classification, 12

the three great classes, of, 13, 14
Rosenbusch, H., cited, 127



St. John, N. B., 128
Sands and sandstones, 97

analyses, 97

metamorphism of, 99

mineralogical composition, 98

occurrence. 99

varieties, 98
Sandstones, 126
Sanidine, 5
Saprolite, 155
Scapolite, II
Schists, 137
Scorias, 26

Secondary minerals, 12
Sedimentation, 94

agents of, 95
Selenite, 115
Serpentines, 150-153

alteration, 153

composition, 150

distribution, 153

varieties, 152
Seven Devils, Idaho, 129
Shales, 126

and clays, 100

analyses, 100

metamorphism of, 102

mineralogical composition, 101

occurrence, 102

varieties, 101
Sheets, 15
Shonkinite, 45
Siderite, n

Silica, molecular ratios, 169
Silicates, 4
Siliceous limestones, 105

oolite, 116-118

sinter, 109- in
Mllimanite, II
Slates, 114, 145-148

alteration. 147

composition, 145

development, 145, 146

distribution, 148
Slates, varieties, 145
Slaty cleavage, 147
Smyth, C. H., Jr., cited, 153, 158
Soda, molecular ratios, 172
Soapstone, 150-153
Sodalite-syenite, 46
Sorby, H. C., cited, 146
Sparta, N. J., 109
Specific gravity, 20
Spheroidal granite, 36
Spherulites, 26
Stalactites, 114
Stalagmites, 114
Standard minerals, 170
Stassfurt, 115
Staurolite, n
Steatite (see soapstone)



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INDEX.



Stratification, 95


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Online LibraryJames F. (James Furman) KempA handbook of rocks, for use without the microscope → online text (page 26 of 27)