Page:Popular Science Monthly Volume 12.djvu/80

70 mile distant from that where Mr. Frere made his discoveries in 1800. The pit has now been worked up to some farm-buildings that interfere with its progress southward, and to get clay they have now crossed the road into the park, and thus made a most important addition to the section laid open.

I have in the accompanying plate given three sections of the ground. The first shows the theoretical relation of the beds according to Prof. Prestwich; the second exhibits the facts actually observed by Prof. Prestwich and myself; and the third is a theoretical section showing the relation that the beds hold to each other according to my own views. We shall in the first place confine our attention to the second section (Fig. 4), showing the facts actually observed.



On the east side of Gold Brook a cutting has been made into the bank, and a thick bed of bowlder-clay is exposed. At the point A in general section the beds are shown, as in Fig. 6. Near the line of division the upper and more chalky clay contains many large flints and transported bowlders. Some of these are smoothed, and strongly scratched and grooved. Two scratched blocks of septaria that I saw measured one and a half foot across. This bowlder-clay, both in its upper and lower division, is very distinct in appearance and composition from that lying above the gravels, as seen in other sections. Lower down toward the brook a seam of false-bedded sandy gravel comes in between the bowlder-clay and the "trail," and represents, I think, the gravels of Figs. 1 and 2.

Crossing the brook and ascending the opposite slope, we have, at the points C and D of general section, typical sections of the clay, pit, as shown in Fig. 7. The clay (4 in section) is called "red-brick earth" by the workmen, because it burns to a red color; while the lower, dark-colored clay (7 in section) is called "white-brick earth," because it burns to a white color. The bottom of the latter bed has not been reached, although Prof. Prestwich had a boring put down into it to a depth of seventeen feet. It is full of vegetable matter, and I found numerous pieces of wood in it. The men pointed out to me the gravel-seams (5 in section), as the horizon at which flint implements had been found; but, shortly before Prof. Prestwich visited the