310 _ A. Tylor on the Amiens Gravel. 
feet above the sea); a straight line from the Ferme de Grice, 
201 feet above the sea to the Somme, 61 feet above the sea, 
passes over the railway 8 feet above the rails, and 23 feet above 
the surface of the chalk at that point, so that the surface of the 
chalk is concave to the extent of 23 feet. At the Imperial 
road the surface of the chalk is concave to the extent of 22 feet, 
although on the upper part it is convex to the extent of 1) 
feet. 
IV. Cuaracrers or THE CHALK, GRraveEL, AND Loxss. 
I will not trouble the Society with the details of Section NQ — 
(Plate IV, fig. 8), but will now proceed to describe the charac — 
ters of the chalk, the gravel, and the loess, as I have o : 
them near Amiens. ele 
1. The Chalk.—The condition of the chalk itself near Amiens ~ 
is remarkable in some places. 
In a railway section near Pont de Metz, about three miles 
from Amiens and Montiers, the chalk surface slopes northward 
at an angle of 20°, and is overlain by 20 feet of d 7 
dipping 10° N. where they touch the chalk, but filling up the 
concavities of the chalk, and having their upper surface slopiig i 
northward at an angle of 3°. ‘ 4 
At Pont de Metz the chalk is covered witha drift challe-mat, 4 
and with beds of chalk rubble and chalk pellets, with very 
tle mixture of sand or clay, 15 to 20 feet thick. cre 
Near Guigencourt, a quarry in the chalk on the pa ' 
four miles south of Montiers, the chalk is very much sp ns : 
- by joints lying at an angle of eighty degrees, or Vey oft | 
vertical, and also nearly at right angles to the planes 
ding of the chalk. (Fig. 2.) 
ay 
ros i Bad 
Ba i Ger 
s fis 
inches wide, and extending to a considerable depth 
« seems as 
