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[Assembly 
Garnet. A hard reddish or brownish mineral usually crystallized in the 
form of a solid having twelve rhombic or diamond shaped faces or 
planes. 
Geology. A science which has for its object the investigation of the 
structure of the earth and the materials of which it is composed. 
Connected with these investigations, are deductions which may be 
derived legitimately from the known influences and efl'ects of causes ; 
these are employed as expressions of the modus operandi by which 
the earth has deen brought to its present state. 
Gneiss. A stratified primary rock, composed of quartz, feldspar and 
mica. 
Granite. An unstratified rock, composed of quartz, feldspar and mica. 
Grauwacke, graywacke. The name was originally applied to a rock 
composed of grains and pebbles cemented together by clay. It be- 
longs to the transition series. The name is appHed also to a group 
of rocks in the same series, consisting of sandstone, slates or shales, 
alternating with limestone, sandstone, &c. The term is rather in- 
definite, yet very frequently used. 
Green sand. Beds of sand, sandstone, limestone and marly clays, in- 
termixed somewhat with greenish particles, belonging to the creta- 
ceous period, and situated beneath the true chalk. 
Greenstone. A variety of trap, composed of feldspar and hornblende. 
Grit. Coarse grained sandstone. 
Gypsum. A mineral composed of sulphuric acid and lime. 
Hornblende. A mineral, usually of a dark green colour ; crystallizing 
in long slender prisms. 
Hornstone. A silicious translucent mineral, resembling flint, but tough 
and more diflicult to break. 
Incandescent. White hot — a degree of heat more intense than that at 
redness. 
Iceberg. Floating masses of ice. 
Ichthyosaurus. A fossil reptile, intermediate between the crocodile and 
fish. A fish lizard. 
Induction. A consequence, conclusion or inference, or some general 
principle drawn from facts or phenomena. 
lo-situ. Original position. 
Isothermal. Equality of temperature. Zones, lines, &c. where an 
equality of temperature prevails are called isothermal. 
Lacustrine, of or belonging to a lake. 
LamincB. Plates, sometimes used as synonymous with layers. 
Landslip. Land which has slidden down an inclined plane, from its 
position in a bank or terrace. It is generally produced by water, 
which either undermines the mass of earth, or insinuates itself into 
it, so as to render it semi-fluid. 
Li7ie of bearing. The point of compass to which the anticlinal ridge 
or line runs, or is directed. When the antiangle ridge cannot be de- 
termined, the line of direction may be known by ascertaining the 
intersection of the planes of the strata with the plane of the horizon, 
that will be the line of bearing. 
