571 
The break between the Trias and Permian seems hardly 
equal in amount to many of the subordinate unconformities 
in the palaeozoic rocks. 
May we not, therefore, reconsider the evidence upon which 
one of our greatest divisions, that into primary and secondary, 
is founded. 
The great change in the Fauna, as a group, and the new 
conditions implied by the appearance of such rank vegeta- 
tion, should weigh more than the persistence of a few genera 
through Silurian and Carboniferous times, and, coupled with 
such clear stratigraphical evidence, force us to draw our 
broadest line at the base of the Old red conglomerate of 
Westmoreland. 
The Glacial Drift. 
I will now skip over a great interval, and offer a few 
remarks upon the Glacial period, and some phenomena to be 
referred to still more recent times. 
There would appear to be three drifts, distinguishable in 
sections, though it is often impossible to trace the boundary 
between them on the surface. 
The lowest is a stiff blue or brown clay — sometimes so hard 
that it is difficult to pick a bit out with a hammer — full of 
stones which are mostly rounded, the larger number striated, 
not transported from any great distance, though not always 
derived from rocks in the immediate neighbourhood. The 
only places where I feel sure of it are in positions where it 
would be in part protected from glaciers flowing along the 
present valleys ; as, for instance, under a great thickness of 
the lighter drift in the deep gorges coming down from the 
Howgill Fells, on the north of Sedbergh, and in the deep 
valley between Lupton High and Farleton Fell, west of 
Kirkby Lonsdale. 
Next there is the common clay drift, which is generally of 
a looser, more stony character than the last, hangs on every 
