vity or declivity of the metals is small, the most extensive 
and regular fields of iron-stone are to be found, and vice- 
versa where the metals lay more on edge. 
Iron-stones are generally found imbedded in schistous 
clay more or less compact, but which moulders away when 
exposed to air. They assume two different forms : regu- 
lar connected strata called bands , and strata of detached 
stone found in distinct masses, from the size of the small- 
est bullet to the weight of several hundred pounds. 
Those of the small and middling sizes, and which gene- 
rally wear a flat ovular form, are called ball-stones : those 
of greater weights are by the workmen denominated lank* 
ers . 
Both these species of iron-stone frequently accompany 
coal and limestone. In the former case they are common- 
ly incumbent, and found almost in immediate contact 
with the coal : little extra labour is therefore requisite t® 
bring down the stone ; and the double purpose of obtain- 
ing both materials is thus advantageously answered. 
When iron-stone in bands accompanies limestone, it 
is most commonly of an inferior quality. Its component 
parts are chiefly calcareous, and the quantity of iron it 
contains is smalL Bali iron-stones found near to lime are 
of a much superior quality, and for the most part contain 
4 considerable proportion of iron. 
Thus stratified in the vicinity of lime, many iron-stones* 
are found with various impressions of marine remains ; 
and not unfrequently compact and entire shells, univalve 
and bivalve, are found in the heart of the band. It is 
however still more difficult to conceive how shells could 
be deposited, distant from lime, imbedded in iron-stone, 
incumbent on coal, at the great depth of 80 yards from the 
surface. In our neighbourhood, at this depth, a small 
band of iron-stone is found completely covered and inter- 
spersed with distinct muscles of an ordinary size. 
