7 



THE POPULAR SCIENCE MONTHLY. 



mile distant from that where Mr. Frere made Ids discoveries in 1800. 

 The pit has now been worked up to some farm-buildings that inter- 

 fere with its progress southward, and to get clay they have now 

 crossed the road into the park, and thus made a most important ad- 

 dition 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 accord- 

 ing to Prof. Prestwich ; the second exhibits the facts actually ob- 

 served by Prof. Prestwich and myself; and the third is a theoretical 

 section showing the relation that the beds hold to each other accord- 

 ing to my own views. We shall in the first place confine our atten- 

 tion to the second section (Fig. 4), showing the facts actually observed. 



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Fig. fi. 1. "Trail," three feet. 6' and 6. Bowlder-clay, chalky in upper part: a slight line of divis- 

 ion between it and the lower part, which is principally composed of crushed Kituiueridg-e clay with 

 pieces of chalk. 



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-clny, both in 

 its upper and lower division, is very distinct in appearance and com- 

 position 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 imple- 

 ments had been found ; but, shortly before Prof. Prestwich visited the 



