Seams of graphite may therefore represent accumulations of vegetal matter such as seaweed.

Coal accumulated in the presence of water; for it is only when thus protected from the air that vegetal matter is preserved.

There were likewise fragments of green carbonate of copper and kaolin, a yellow ocher, and considerable vegetal matter mixed with the sand.

Feeding on vegetal matter in the luscious swamps, and having their vast bulk lightened by their aquatic life, they soon attained the most formidable proportions.