4] 
ORGANIC IMPRESSIONS. 
The second great division of fossil impressions 
is called OrGanic, meaning impressions made by 
organized bodies; the bones of animals, fishes, and 
vegetables. 
Near one extremity of the slab of the Ornithopus 
Gallinaceus is an elevation, about a foot long, and 
between one and two inches wide, projecting from the 
surface nearly half an inch. It has the appearance of 
a round bar of iron imbedded in the rock, which is 
clayey sandstone. This apparent bar of iron was 
probably a bone, buried in the stone, now silicified 
and impregnated with iron; the animal matter having 
entirely disappeared. In the slab of the Brontozoum 
Sillimanium is a projection about seven or eight inches 
long, and half an inch wide; probably the bone of 
an animal, perhaps a clavicle of the Brontozoum 
Giganteum. 
