79 
11. 
12. 
13. 
14. 
15. 
16. 
Avs 
PHILOSOPHICAL SOCIETY 
. A bed of sand with its upper 
surface horizontal, having a 
thickness of about 1’ at one 
side of the shaft and 4’ on the 
other. 
A stratum, about 2’ thick, of 
sandy mud, containing lignite. 
The lamine of this bed were 
horizontal, while its upper sur- 
face fell from north to south 
at the rate of about one in 
eight. 
6’ of sand containing nodules of 
iron pyrites, isolated masses 
of lignite, and pockets of red 
clay. 
A bed of fine, clean sand, con- 
taining here and there a little 
clay. This bed was 9 thick, 
and gradually gave way to the 
succeeding bed. 
A bed of sandy kaolin, 6’ thick, 
very wet and difficult to work. 
It was a regular mortar-bed 
in consistence. 
A layer, 2” to 4” thick, of hard, 
ferruginous conglomerate. 
¥ of blue-grey clay, hard, com- 
pact, and possessing a very 
unctuous feel. This bed con- 
tained a bunch of rootlets, the 
first trace of organic remains 
below the lignite of No. 11. 
A bed of clayey sand, streaked 
with red, blue, and grey, 7’ 
thick, and gradually running 
into the subjacent stratum. 
OF WASHINGTON. 
4 F 
a 
88 
k 
BER BsQs 
24 
Fig. 3. Geological Section at Water-Works’ Shaft. 
