188 Burton: The Cleveland Ironstone. 
of section, which is entirely contrary to what might be expected 
judging from experience elsewhere. Again, in the case of 
Stanghow (M) the bottom block of ironstone is lithologically 
so much like the middle band that it is difficult to distinguish 
the one from the other as they appear in the seam. 
I have drawn a subsidiary line of sections from Liverton 
Shaft (N2) for 1} miles South to N. The rapid alteration in 
the main seam along this line is remarkable. Thus the two 
feet of the middle dogger, which was very ferruginous, and was 
worked with the stone, at the shaft becomes split into 1 ft. 2 in 
of shale and ro in. of dogger, 638 yards to the south, and is a 
very silicious shale 1} miles from the shaft. 
From this last point is a line due west to the present position 
of the workings in Kilton pit, and the mines manager kindly 
Dogger g in 
Shale Tite San 
Dogger 8 in 
i ames BE 6 
but doubtless the dogger is sufficiently ferruginous to be 
worked as an ironstone. 
When I first began to prepare these sections I had the 
expectation that I should be able to discover some general 
principle which would sufficiently explain the variations in 
thickness, quality, and nature of the deposit, but in this I 
have quite failed, as there are so many and such striking local 
exceptions to the rule which would seem to generally apply, 
that any deductions are now necessarily put forward tentatively 
and with diffidence. 
If in the comparatively few sections which are obtainable 
inland, there are such unexplained differences ; what may there 
not be in places yet to be opened up? Almost every writer 
since Bewick’s time has drawn his conclusions from such 
premises as were available at the time, and generalized from 
limited areas of investigation ; and each succeeding writer on 
the same subject has found it necessary to modify some of his 
predecessors’ statements. One of the most cautious and reli- 
able of men —the late C. Fox Strangways, made the same 
error when he said of the changes in the character of the main 
seam, ‘These changes are so extremely regular that the 
thickness of the ironstone at any point may be calculated from 
the nearest known sections.’ This is not quite borne out by 
facts, and therefore any opinions now expressed are merely 
based on a careful consideration of present knowledge. It 
does, however, seem from the evidence, even including the 
absence of regularity, that there is justification for the opinion 
Naturalist, 
