S<50 
A GLOSSARY OF GEOLOGICAL TERMS. 
Fault , interruption of the continuity of strata with displacement.-— Felspar , s 
mineral which enters into the composition of many Primary rocks.-— Formation , 
group, series, system; terms applied to any class of rocks presumed to have been 
formed during one geological epoch. 
Galt , a provincial term applied to the Blue Marl of the Chalk formation.—- 
Gneiss , a primary rock, allied to Granite.— Granite , a Primary rock, composed of 
Mica, Quartz, and Felspar.— Greensand (or Shanklin Sand), the lowermost 
strata of the Chalk-formation.— Greenstone , a Trap rock.— Greywacke, a Transi¬ 
tion rock; a conglomerate indurated by heat.— Grit, coarse-grained Calciferous 
Sandstone.— Gypsum , Sulphate of Lime. 
Iguanodon, extinct colossal Lizard, having teeth like those of the Iguana.— 
Imbricated, laid one over the other like scales.— Inoceramus, a bivalve shell of 
the Chalk, having a fibrous structure.* 
Kimmeridge Clay , a blue Clay of the Oolite. 
Lacustrine , belonging to a lake.— Lamellated , covered with thin plates or 
scales.— Laminae, the thin layers of which a stratum is composed.— Laminated, 
strata formed of very thin layers.— Lapilti , volcanic ashes, in which minute 
globular concretions prevail.— Lias, a provincial term, applied to a group of strata 
situated between the Oolite and the New Red Sandstone.— Lignite, Carbonised 
wood.— Lithodomi, Mollusca which perforate stone.— Lithological, the stony 
character of a mineral mass.— Lithophytes, stony plants; a term applied to 
Oorals.— Loess, an alluvial Tertiary deposit on the banks of the Rhine.-—■ 
Lophiodon, a fossil animal, allied to the Tapir, so named from the eminences oir 
the teeth. 
Mammillated, studded -with mammillae, or rounded protuberances.— Marl, a 
mixture of Clay and Lime.— Marsupite, a genus of Crinoidea of the Chalk.— 
Matrix, the substance in which a fossil is embedded.— Meandrina, a genus of 
Corals, with meandering cells, as the Brain-stone Coral.— Megalosaurus, gigantic 
Lizard; an extinct Saurian, allied to the Monitor.— Megalonyx, an extinct 
quadruped, allied to the Sloth.— Meteorites, mineral masses which fall from the 
atmosphere.— Megatherium, an extinct gigantic quadruped, allied to the Sloth.— 
Mica, a simple mineral, one of the component parts of Granite.— Miocene f 
middle Tertiary series.— Multilocular, many-chambered shells, as the Nautilus.— 
Muschelkalk, a Limestone of the Red-Sandstone-formation. 
New Red Sandstone, a group of strata between the Magnesian Limestone and 
the Lias.— Nodule, a rounded mineral mass, as a Flint.— Nummulite, an internal 
multilocular shell. 
Obsidian, a glassy lava .—Old Red Sandstone, a group of strata lying between 
* See Geol. of the S.-E. of England, p. 127 —Ed. 
