natural history, the name of a genus of fossils, of the class of the septariae, the characters of which are; that they are bodies of a dusty hue, divided by septa, or partitions of a sparry matter, into several more or less regular portions, of a moderately firm texture, not giving fire with steel, but fermenting with acid menstrua, and easily calcining.

The septariae of this genus are, of all others, the most common, and are what have been known by the little expressive, or mistaken names of the waxen vein, or ludus helmontii. We have many species of these bodies common among us. Of the whitish or brownish kinds we have thirteen; of the yellowish five; and of the ferruginous ones, four.