See also:

• PHYLLITE (Gr. 40)XAov, a leaf, probably because they yield leaf-like plates, owing to their fissility)

PHYLLITE (Gr. 40)XAov, a See also:

• LEAF (O. Eng. leaf, cf. Dutch loof, Ger. Laub, Swed. lof, &c.; possibly to be referred to the root seen in Gr. Ma-eta, to peel, strip)

leaf, probably because they yield leaf-like plates, owing to their fissility)  , in See also:

• PETROLOGY

petrology, a See also:

• GROUP

group of rocks which are in practically all cases metamorphosed argillaceous sediments, consisting essentially of See also:

• QUARTZ

quartz, See also:

• CHLORITE

chlorite and See also:

• MUSCOVITE

muscovite, and possessing a well-marked parallel arrangement or schistosity . They See also:

• FORM (Lat. forma)

form an intermediate See also:

• TERM

term in the See also:

• SERIES (a Latin word from serere, to join)

series of altered See also:

• CLAYS, PAUL JEAN (1819-1900)

clays or shaly deposits between See also:

• CLAY (from O. Eng. claeg, a word common in various forms to Teutonic languages, cf. Ger. Klei)
• CLAY, CASSIUS MARCELLUS (1810-1903)
• CLAY, CHARLES (1801–1893)
• CLAY, FREDERIC (1838–1889)
• CLAY, HENRY (1777–1852)

clay-slates and See also:

• MICA

mica-See also:

• SCHISTS (Gr. vxq'ecv, to split)

schists . The clay-slates have a very similar See also:

• MINERAL

mineral constitution to the phyllites, but are finer grained and are distinguished also by a very much better cleavage . In the phyllites also See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white mica (muscovite or sericite) is more abundant as a See also:

• RULE

rule than in See also:

• SLATE (properly CLAY SLATE; in M. Eng. slat or sclat, from O. Fr. esclat, a small piece of wood used as a tile; esclater, to break into pieces, whence modern Fr. eclat, the root being seen also in Ger. schleissen, to split)

slate, and its crystalline plates are larger; the abundance of mica gives these rocks a glossy sheen on the smooth planes of fissility . Many of the best Welsh slates are See also:

• RICH, BARNABE (c. 1540-1617)
• RICH, CLAUDIUS JAMES (1787-1821)
• RICH, JOHN (1692-1761)
• RICH, PENELOPE, LADY (c. 1562–1607)
• RICH, RICHARD, 1ST BARON RICH (1490?-1567)

rich in small scales of white mica, which polarize brightly between crossed nicols . The Cornish slates are still more micaceous and rather coarser grained, so that they might be called mica-slates or even phyllites . A microscopical See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section of a typical See also:

• PHYLLITE (Gr. 40)XAov, a leaf, probably because they yield leaf-like plates, owing to their fissility)

phyllite shows See also:

• GREEN, A
• GREEN, ALEXANDER HENRY (1832—1896)
• GREEN, DUFF (1791—1875)
• GREEN, JOHN RICHARD (1837—1883)
• GREEN, MATTHEW (1696-1737)
• GREEN, THOMAS HILL (1836-1882)
• GREEN, VALENTINE (1739–1813)
• GREEN, WILLIAM HENRY (.1825–1900)

green chlorite and colourless mica both in irregular plates disposed in parallel See also:

• ORDER
• ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
• ORDER, HOLY

order, with a greater or smaller amount of quartz which forms small lenticular grains elongated parallel to the foliation . Grains of See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron See also:

• OXIDE

oxide (See also:

• MAGNETITE

magnetite and See also:

• HAEMATITE, or HEMATITE

haematite) and See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black graphitic dust are very commonly See also:

• PRESENT

present . Feldspar is absent or scarce, but some phyllites are characterized by the development of small rounded grains of See also:

• ALBITE

albite, often in considerable See also:

• NUMBERS, BOOK OF
• NUMBERS, PARTITION OF

numbers . The See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute needles of See also:

• RUTILE

rutile, so often seen in clay-slates, are not often met with in phyllites, but this mineral forms small prisms which may be intergroivn with black magnetite; at other times it occurs as networks of sagenite . Other phyllites contain See also:

• CARBONATES

carbonates (usually See also:

• CALCITE

calcite but sometimes See also:

• DOLOMITE

dolomite) in See also:

• FLAT (a modification of O. Eng. flet, an obsolete word of Teutonic origin, meaning the ground beneath the feet)

flat or spindle-shaped crystals, which often give See also:

• EVIDENCE (Lat. evidentia, evideri, to appear clearly)

evidence of crushing . Very tiny See also:

• BLUE (common in different forms to most European languages)

blue needles of See also:

• TOURMALINE

tourmaline are by no means rare in phyllites, though readily overlooked .

See also:

• GARNET
• GARNET, or GARNETT, HENRY (1555—1606)

Garnet occurs some-times, a See also:

• GOOD, JOHN MASON (1764-1827)

good example of garnetiferous phyllite being furnished by the whetstones of the See also:

• ARDENNES

Ardennes, in which there are many small isotropic crystals of magnesian garnet . See also:

• HORNBLENDE

Hornblende, often in branching feathery crystals, is a less frequent See also:

• ACCESSORY

accessory . In some phyllites a mineral of the chloritoid group makes its See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance; this may be ottrelite, sismondine or other varieties of chloritoid, and occurs in large sub-hexagonal plates showing complex twinning, and lying across the foliation planes of the See also:

• ROCK
• ROCK (O.Fr. rake, Sp. rota, Ital. rocca; possibly from a Lat. form rupica, from rupes, rock)
• ROCK, DANIEL (1799–187t)

rock, so that they seem to have See also:

• DEVELOPED

developed after the movements and pressures which gave rise to the foliation had ceased . The structural See also:

• VARIATIONS
• VARIATIONS, CALCULUS
• VARIATIONS, CALCULUS OF

variations presented by the phyllites are comparatively few . The most finely crystalline specimens have generally the most perfect parallel arrangement of their constituents . The foliation is generally flat or linear, but in some rocks is undulose or crumpled . From the imperfection of their cleavage phyllites are rarely suitable for roofing materials; their softness renders them valueless as road stones, but they are not uncommonly employed as inferior See also:

• BUILDING

building materials . They are exceedingly See also:

• COMMON

common in all parts of the See also:

• WORLD

world where metamorphic rocks occur; as in the Scottish See also:

• HIGHLANDS, THE

Highlands, See also:

• CORNWALL

Cornwall, See also:

• ANGLESEY, ARTHUR ANNESLEY
• ANGLESEY, HENRY WILLIAM PAGET
• ANGLESEY, or ANGLESEA

Anglesey, See also:

• NORTH
• NORTH, BARONS
• NORTH, MARIANNE (1830—1890)
• NORTH, ROGER (1653-1734)
• NORTH, SIR THOMAS (1535?-16o1?)

north-See also:

• WEST
• WEST, BENJAMIN (1738-1820)
• WEST, NICHOLAS (1461-1533)

west See also:

• IRELAND
• IRELAND, CHURCH
• IRELAND, CHURCH OF
• IRELAND, JOHN (1761-1842)
• IRELAND, JOHN (1838- )
• IRELAND, WILLIAM HENRY (1777-1835)

Ireland, the Ardennes, the Harz Mountains, iSaxony, the See also:

• ALPS

Alps, See also:

• NORWAY
• NORWAY (Norge)

Norway, the Appalachians, the See also:

• GREAT

Great Lakes See also:

• DISTRICT

district in See also:

• AMERICA

America, &c . (J . S .