Igneous rocks. Rocks, such as lava, trap, and some others which have been fused by volcanic heat.—Granite and other porphyritic rocks are sometimes called crystalline.
Ignigenous. Produced by fire.
Iguanodon. Extinct gigantic lizard.
Imbricated. Covered with scales overlapping each other like tiles on the roof of a house.
Inoceramus. A bivalve of the chalk formation.
Inorganic. Not produced by vital action.
Invertebrata. Animals not furnished with a back bone.
Juncus (in botany). A rush.
Lacertians. Lizards.
Lacustrine. Belonging to a lake.