A CHAPTER IN THE PHYSICAL GEOGRAPHY OF THE PAST. 41 
The total thickness of this great pile 
of strata is probably over 12,000 feet in 
Derbyshire, and this does not repre- 
sent the whole of the original thickness 
hie of the beds. From the evidently sed?- 
mentary character of all these rocks, we 
‘a are quite sure that the materials were 
\ laid down under water, in a horizontal 
or almost horizontal position; but we 
now find them elevated considerably 
above the level of the sea, and with 
their original bedding lines inclined to 
: ALS Poe, = tt 
& 
the horizon at all sorts of angles. The 
true relation of such beds to each other, 
and to the present conformation of the 
surface can only be ascertained when 
a large district has been surveyed, and 
all the outcrops of the strata laid down 
on a map with the observed inclina- 
tions, or dp of the strata, as it is called. 
From such maps it is possible to con- 
ke Anise) Butt. 
Z Red Rok Fautt 
Distance asouT 35 MILEs. 
Sete Tee 
ee 
struct imaginary sections across a 
country, showing at a glance the pre- 
sent position of strata, which once 
a Lower Gal Measures. 
2 ew em res 
eae ee ~ 
forming horizontal and continuous 
sheets, may now have become folded, 
faulted, and disconnected, in all sorts 
of complicated ways. 
You have before you such a horizon- 
tal section taken along an east and 
west line across the Pennine Range, 
from about eight miles north-east of 
Chesterfield, through Buxton to Mac- 
clesfield, a total distance of about 35 
miles. This section must be considered 
as diagrammatic, for besides having its 
DriaGRAMMATIC SECTION across PENNINE ANTICLINAL, 
a Carhoniferous Limestone. 
b Yorectales. 
¢ Millstone Grit. 
