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A, Tylor on the Amiens Gravel. 307 
_ The gradient continues falling east 1 in 88,1 in 180, 1 in 
160, 1 in 41, 1 in 33, and rising 1 in 200 to the east, where it 
_ teaches the escarpment at a height of 1423 feet above the sea. 
‘The loess is here 5 feet thick, and the gravel 2 feet, accord- 
_ ing to Mr, Guillom’s survey; but I found only two or three 
_ feet where I observed it, The loess is 5 feet thick near the 
_ tramway, and 4 feet at the point D. The gravel is 13 feet 
- thick at D, and 10 feet thick at the tramway, thinning out as 
_ itapproaches the escarpment on the east, as it did on the west. 
_ The surface of chalk is horizontal throughout this section also 
up to the escarpment. 
___ Atthe escarpment, the chalk falls to the east 52} feet in a dis- 
tance of 106, or at an angle of 45° and gradient of 1 in2 
 Rearly. The line of slope of this escarpment is remarkably 
_ Straight in many places, and quite free from gravel or loess. 
_ Then there follows a flat terrace of loess, 60 feet wide, then a 
Shope toward the river, of 1 in 30, and then 1 in 4, until we 
teach the marsh at a height of 761 feet above the sea. 
II, Descrrerions oF THE TRANSVERSE SECTIONS. 
__ Section IK (Plate IV, fig. 6).—This section commences at 
a the Rue de Cagny, point I, at a height of 200 feet above the 
_ Xa, and falls to the river and the north ata gradient of 1 in 
2,1 in 28, 1 in 22, 1 in 18, 1in 54, It then rises to the north 
atl in 162, and crosses the tramway ballast-pit ata level of 1532 
above the sea, and the Imperial Road at a height of 153 
above the sea; it then rises to the north at a gradient of 1 
a it reaches the Somme. 
i. the point I in the Rue de Cagny the loess is 3 feet thick, 
