306 A, Tylor on the Amiens Gravel. 
It passes through the celebrated pits of St. Acheul, and is 
bounded by the river Arve, a tributary of the Somme, atits 
eastern point, C, and by the escarpment of chalk in the Rue 
de Cagny (700 yards west of the railway-station, Amiens) at 
its western extremity, point H. | 
C H is near the Imperial Road, and is parallel to that road, 
to the railway, and to the river Somme. 
Section G H.—The length of G H is 1400 feet. See Plate 
IV, fig. 5. The highest point is 157 feet above the sea, 79 feet 
above the river Arve, 3 feet over the highest part of the Im 
perial road, 61 feet above therails, and 84 feet above the rivet 
Somme at Neuville. The gradient, commencing at point 
129 feet above the sea, Rue de Cagny, rises to the east Lin 3, 
then 1 in 33, 1 in 35, 1 in 61, and 1 in 100, reaching the well 
known section of St.-Acheul Pit, with Roman graves, fossili- 
erous sand, and wavy marls, at a height of 1522 feet above the 7 
sea. A portion of this is shown in Plate IV, fig. 12, | 
The loess in this section is four feet at the highest, and most ) 
easterly point, G, gradually thinning to the west, and ceasilg 
when it reaches H. alk 
The gravel is sixteen feet thick at its most easterly point, 9, 
thinning out as it passes to the west a little before the los 
disappears. it 
The surface of the chalk is 133 feet above the sea at Gam 
128 feet at H. The surface falls 1 in 280 to the west. pels 
Section E F—The surface gradient commences at F, 
t, 
at The regularity of the loess is a very important” 
The gravel is 17 feet thick at F, and 15 feet at E. ie j f, 
showing a perfectly horizontal line, while there 18 OM) 
tion in the level of the surface-loess of 3 feet in this gecti0?, q 
D with an elevation of 153% feet above the sea, zy a0 
falls to the east 1 in 40 and 1in 300, Here the tray ie : 
IV, fig. 1) crosses the Imperial Road, and some very ; 
gravel pits are now being worked for ballast. 
