Glossary. 
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Felstone. A rock of igneous origin, compact in structure, 
often chemically identical with granite, but not show- 
ing. the holo-crystalline structure of granite. 
Fenestellidse (Lat. fenestella , a little window). The 
“Lace-corals,” a group of Palaeozoic Polyzoans. 
Flora (Lat. Flora , the goddess of flowers). The general 
assemblage of the plants of any region or district. 
Foliation (Lat. folium^ a leaf), Splitting into layers. 
Gabbro. A rock, not unlike coarse-grained basalt, and 
usually containing a special variety of augite, which 
has a “ platy ” structure. 
Ganoid (Gr. ganos , splendour, brightness). Applied to 
those scales or plates which are composed of an inferior 
layer of true bones, covered by a superior layer of 
polished enamel. 
Garnet. A very varied group of minerals, the commonest 
being wine-red ; they are all silicates of alunmia, and 
among other possible constituents are iron, magnesia, 
lime, and manganese. Some red garnets are valued as 
gems. 
Gasteropoda (Gr. gaster , stomach ; pons , a foot). 
The class of Mollusca comprising the ordinary 
Univalves, in which locomotion is usually effected by 
a muscular expansion of the under surface of the 
body (the “foot”). 
Gneiss. A rock composed of the same minerals as granite, 
but exhibiting a certain bedded or leaf-like arran de- 
merit of its constituent minerals, called foliation. 
Granite. A rock of igneous origin, composed of crystalline 
constituents, the principal being quartz, felspar, and 
mica. 
