TTJTE : SEQUENCE OF PEBMIAN BOCKS. 219 
least 50 feet in thickness, of a peculiar character. The surface of 
each layer is irregularly covered with small lumps or bosses, as if the 
Permian sea had been subjected to a set of various cross currents, 
which disturbed the natural process of horizontal stratification. It is 
a somewhat dark, yellowish, unfossiliferous limestone, full of the 
sparry cavities so characteristic of the Magnesian limestone. To 
this bed succeed others of solid limestone, which form the main 
deposits of the district, and are probably about 275 feet in thickness : 
they are quarried at Wormald Green, Markenfield, Quarry Moor, 
and in many other places. In some of its lower beds this limestone 
is a good building stone, of an agreeable creamy-white colour ; but 
more suitable for interior than exterior work. Fossils are occasion- 
ally found, as in two layers in an old quarry near Wormald Green. 
Old weathered stones also occasionally exhibit the presence of fossils, 
though they can seldom be separated from the matrix. In the 
upper beds in a quarry a short distance west of Markenfield Hall, 
there are many casts of fossils. Here the limestone is of a darker 
colour, and not so pure. 
In the quarry belonging to Markenfield Hall, the limestone 
presents in its structure a close resemblance to the limestone at 
Ryhope, in the county of Durham, and in an old wall near the Hall 
I have found a portion of limestone of the same hard semi-crystallized 
form as that of Tunstall Hill, but have never discovered the bed 
from which it was taken. We may, therefore, assign the Markenfield 
beds to the same horizon as the Ryhope Limestone. Belonging to 
the main limestone there is a bed which is perfectly oolitic in an old 
quarry in Whitcliffe Lane. At Nidd Rock an oolitic limestone has 
disintegrated into a kind of gravel of small rounded grains, but larger 
than those in Whitcliffe Lane. 
The whole of these rocks seem to have been deposited in a 
shallow sea ; for at Wormald Green the clay-partings are strongly 
ripple-marked, and many layers, when weather-worn, exhibit marks 
of false-bedding. Above the main limestone I am inclined to place 
the beds of Gypsum, which occur north of Ripon. They consist of 
layers of Gypsum and a red sandy clay which have been violently 
contorted, and they are about 40 feet in thickness. They are over- 
