23a 
at “ Oakhill Quarry ,” Epping Forest. 
shall have faults on the western side of each. There is no 
doubt that the western slopes have the same character with 
each other, in both cases being considerably steeper than the 
eastern ones. 2 Until the dip of the beds has been more 
accurately ascertained, fig. 1 will give an approximately 
correct idea of the strata in this part of Essex. The section 
is constructed from those given in vol. iv. of the ‘ Memoirs of 
the. Geological Survey,’ where sections are described at 
Hainault Forest, Loughton, Waltham, and Waltham Cross; 
and particularly from the section of a well dug a few years 
since at Loughton by the Great Eastern Bailway Company, 
for the particulars of which I am indebted to Mr. Langley, 
Engineer to the Company, who has kindly furnished me with 
the same. Unfortunately, I learn from him that no fossils 
were obtained when digging this well, the only one, I believe, 
in this part of Essex which passed through the Chalk. The 
section is given in the diagram (fig. 1), and is as follows:— 
Depth to the Chalk 
Feet. 
243 
Chalk ..... 
648-6 
Chalk and Upper Greensand . 
37 
Gault ...... 
132-6 
Gault-Pebbles 
31-6 
1092-6 
The upper beds of the clay pass by almost imperceptible 
gradations from clay to sand into the Bagshot Sand, which 
is succeeded by the Bagshot Pebble-bed, consisting of flint 
pebbles. These beds, although once covering the whole area, 
are now only to be seen in sundry outliers at Brentwood, 
Havering, Theydon Mount, Oakhill, and High Beach. From 
the present slopes and valley-bottoms they have long since 
been denuded away. The principal difficulty about these 
beds, and that is rather a serious one, is to distinguish 
between the pebble-bed of the Bagshot and the later glacial 
gravels, or gravels of denudation, which are to a large extent 
composed of the re-sorted materials of the Bagshot Pebble- 
bed. These beds may be distinguished by their pebbles—the 
Bagshot Pebble-bed consists entirely of flint pebbles well 
2 I venture to throw out the suggestion that the greater steepness of the 
western slopes may be attributed, not to the faults, but to the greater 
denudation to which hills having that aspect have been exposed from the 
prevailing westerly and south-westerly winds and rain, which may have 
had considerable influence upon strata of such a character as the London 
Clay. 
R 
