OF THE DISTRICT. 
185 
the alternating sandstones and shales of the millstone grit and lime- 
stone series, and thus justify the classification of all the groups in 
one carboniferous system, but they are but a subordinate feature in 
a region which derives its great lineaments from rocks which do not 
occur in the true coal tract. 
It is the mountain or metalliferous limestone which gives to the 
north-western part of Yorkshire and to the district of Craven those 
marking and distinctive features, which powerfully interest the geologist 
and the topographer, and lend an indescribable charm to many sweet 
pastoral dales, which lie in the shadow of bold mountains, girt with 
green belts or steep precipices of limestone and crowned with ruinous 
summits of millstone grit. The aspect of the mountain limestone tract 
in Yorkshire is in some degree peculiar: for both to the north and 
south of the county the limestone series is considerably modified ; and 
while in Durham and Northumberland the characters of this rock 
are less conspicuous, in Derbyshire they become more predominant. 
It is further to be remarked that even within the limited range of 
Yorkshire the composition of the limestone series varies so much, as 
to wholly alter the physical aspect of the country, and thus to give 
to the rocks near Ingleborougli some of the massive features of the 
precipices of Derbyshire, and to the moorlands of Teesdale the desolate 
appearance of the valleys on the higher branches of the Tyne, 
The limestone tract of Yorkshire maybe considered as divided into 
two unequal parts, by a line drawn E. S, E. from Kirby Lonsdale to 
Skipton ; the southern portion which is much the smallest forms a part 
of the country of Craven, and is geologically related to the mountain 
limestone of Derbyshire ; the northern portion, which extends eastward 
along the Wharfe to Wetherby and goes northward to Teesdale is a 
part of one vast elevated region which ends abruptly on the southern 
side of the Tyne. The high western border of this region receives the 
appropriate name of Penine chain. 
From the Penine chain to the parallel magnesian limestone ter- 
