ON THE TKAP-ROCKS IN YORKSHIRE, &C. 477 
bed of loadstone, under which it again appears in the third 
hmestone. In a few instances strings and short branches 
of ore have been discovered, but the few veins which pass 
through this substance contain no ore. How to account 
for this unequalled stratified arrangement must require no 
small share of ingenuity. It has been maintained, that the 
toadstooe and limestone, with the metalhc veins of this 
district, are of contemporaneous formation, but the differ- 
ent organic remains in the upper and lower beds of lime- 
stone preclude the possibility of such simultaneous forma- 
tion. CuviER has very justly observed, that the existence 
of different organic remains, offers irresistible proof, that 
the upper and lower strata in which they were found, were 
formed in succession. The rapid progress of the science 
of chemistry, will, it is to be hoped, ere long, dispel the 
darkness, and furnish a solution to this hitherto unex- 
plained phenomenon. 
The great trap mass of Teesdale shews itself on the south 
bank of that river, just opposite to Middleton, in Tees- 
dale, and extends to a great breadth to the Chain-bridge, 
where it forms the bed of the river, which has worn 
a deep chasm through it. At the Highforce (a waterfall 
of 70 feet perpendicular) the river has worn its bed com- 
pletely through it, and shews it resting on the encrinite 
limestone, and dipping regularly to the NE. at an angle 
of not more than 12° with the horizon. Here may be dis- 
tinctly seen, on the right side of the waterfall, the great 
Mar beck vein, intersecting both the trap and the lime- 
stone. This fact is interesting, as to the relative age of 
this trap, shewing it must have been in existence previous 
to the formation of the veins which pass uninterruptedly 
from the other strata through it. I am informed by miners 
this is always the case, and that they very frequently bear 
ore. At Maisebeck, in Tyne Bottom, there is a rib of 
