sion has extended several feet into the Tertiary. There are at least ten logs exposed in this amphitheater which vary considerably in color and composition. Some of them arc almost pure white and apparently contain nearly pure silica; others are stained with more or less of foreign matter.
These logs vary in size and preservation and none of them presents the full length of the original tree. The largest observed is about six feet in diameter by twenty feet in length and is of a brown color.
Fig. 5. Petrified Log from Pittsboro, Miss., now on the lawn of Dr. Calvin S. Brown at the University of Mississippi.
Another is four feet at base by about seventeen feet in length. A dark colored log near by is five feet at base and eleven feet long. Another in a ravine to the east is four feet by twenty feet; and there are still other logs and fragments of logs scattered at various points.
Most of these logs now rest upon the Tertiary formation and therefore are slightly displaced; that is to say, the sand of the Lafayette formation has washed from beneath them and left them lying upon the Tertiary. In several places however in the vertical erosion walls logs are seen projecting from the Lafayette sand some distance above the Tertiary.
In the accompanying illustration, number four, the line of union between the Quaternary and the Tertiary is distinctly seen running horizontally through the middle of the picture. Some distance above this
