A, Tylor on the Amiens Gravel. 311 
tem of joints would very much facilitate the formation, or 
rather the separation, of the chalk into rectangular and imper- 
fect spheroids, such as are seen in the quarries behind St.- 
Acheul and Longueau, where some decomposing agency has 
acted upon the chalk itself with considerable effect. 
In the drawing (fig. 3) made of the condition of the surface 
a Fig. 3.— Section along the St. Acheul and Longueau Road, . 
ee caer eS ee 
a 
i 
~ 2 
~ 
~ 
\ ai ; ; 
(AAR SOc 
helen) 
) along the Saint-Acheul 
and Longueau road, running east and west, I found the sand- 
: Fig. 4.—Section in M. Dailli’s Garden showing decomposed Chalk. 
a N 
al 
“a 2s 
® > cv 
LS 4 z 
ne 
: z 
a ~ S 
oe, % — <i — a 4 
<q ate 2 a Ss i 
LADIES QaAso PSS ES 5 
StS OS oe a 
_ Smposed chalk in the railway-cutting or quarry between 
*ngueau and La Neuville, nor at the ballast-pit in the chalk 
“1 La Neuville at the railway workshops, Amiens. The sur- 
of the chalk, however, is irregular, and covered with gravel, 
mrthout deep pipes, aS 
The drawings of the chalk-quarry, fig. 2, and in M. Dailli’s 
Space 
: 
(ie 
er pieces of chalk are left, often in a boulder-like 
drawn), with slightly rounded or abraded commen, 
between large pieces then being loose and friable, an 
