part of it is exogenous, good specimens of palm-wood are found in south Mississippi.
Most of the petrified wood in the state is found in the Lafayette formation but some is found lower down in the Wilcox and other Tertiary formations. Dr. Hilgard surmised that a great part, if not all, of the silicified wood found in the upper formation was derived ultimately from the several lignitic stages of the Tertiary.
The petrified forest, or speaking more accurately, the group of silicified logs, which I wish particularly to mention in this brief article, is found near Flora, seventeen or eighteen miles northwest of Jackson, the state capital. Here is a large field where erosion is actively taking place at the present time. Throughout the area are scattered logs and fragments in varying stages of disintegration.
An amphitheater some twenty or twenty-five feet deep and about one hundred and fifty feet in diameter, where the Columbia loam and the Lafayette sand have washed away down to the Tertiary formation, offers the best single exhibit of the logs. At the mouth of the valley the ero-
