376 EARTH-MOVEMENTS DURING CARBONIFEROUS TIMES. 
an absence of tangential stress such as Avould be required if 
marginal ridges had been uplifted. They possess, too, the 
radial and peripheral characteristics so suggestive of a subsiding 
area. The almost complete absence of overthrusts and reversed 
faults in the area is a marked feature ; while the fact that so 
many of the faults were intermittent,* in that, while having 
a large throw in the Coal Measures, they reappear with a smaller 
throw in the new rocks above, suggests that careful investigation 
might, in fact probably would, reveal instances of the faults 
having been progressive ones during Coal Measure times. This 
would show itself in a diminished throw in the upper seams. 
There seems to be some evidence of this, though convincing 
sections are not available. 
VI. — Relative Age of Inception of the Charnian aznD 
Market Weighton Axes. 
It will be seen from Fig. 4 that the Charnian axis was re- 
latively stable for some time before the Barnsley seam was 
formed. Its stability was but relative, and at times it partook 
of the motion of the adjoining area. Its function in determining 
the hmits of the Carboniferous rocks in its direction probably 
dates back to post -Silurian times. In the case of the Market 
Weighton axis, it seems to be clear that it was only after the 
formation of the Barnsley seam that it became stable, for marked 
thinning onty appears after that stage. There is evidence, too, 
in recent borings, unfortunately not available for publication, 
along a line normal to the axis, that this condition obtained 
through Triassic times. The Market Weighton axis therefore 
came into existence as a line of relative stabihty after the forma- 
tion of the Barnsley seam, and is posterior in age to the Charnian 
axis. 
VII. — The Age of the Pennine Range. 
The tangential stress that phcated and rolled up the Silurian 
rocks before the laying down of the Carboniferous basement con- 
glomerate was apphed from tlie east. The tectonic relationship 
* Geological Survey, Sujiimary of Progress, 1902, p. 5. 
