44 
DESCRIPTION OF THE ROCKS 
descends from the moors in a deep ravine, and other small becks, but it 
is nowhere deficient, and indeed can be traced from East Witton to 
Parkhead, except about Great Scrafton. 
In the middle of Coverdale the blue limestone series rises above the 
river, and exposes at Gammersgill a flagstone series beneath. The exten- 
sive quarries here produce excellent stone, with carbonaceous surfaces, 
which are often covered with nodules, and vermicular, and ramified 
markings. 
The sections at the head of Coverdale are exceedingly interesting 
with reference to the upper crinoidal limestones, whose diminished and 
debased character is by them found to prevail through the whole of 
this valley, especially on the S. E. side. 
The main lime is seen distinctly encircling the head of the dale 
in a belt of rocks, and is cut through by the streams which enter the 
left bank of the Cover. On the opposite side, beneath Great Whernside, 
this rock is much thinner, but it no where really vanishes from the 
section. It is usually crinoidal in texture, with undulated nodules of 
gray chert. 
On the left (north-west) bank we have, beneath grits and shales. 
Feet. 
50 or 60 ? of the main or Parkhead limestone. 
100 Principally plate. 
15 Limestone, gray crinoidal. 
40 Plates and flaggy grits, with tessular ironstone bands. 
Limestone bine, hard, jointed. 
On the right side of Coverdale, a stream from between Great and 
Little Whernside, gives this section. 
Bearing grit 
Main or Parkhead lime 
Plate and ironstone 
Underset lime ... 
Feet. 
100 
20 with nodules and hands of chert. 
Upper limestone 
90 
10 
