66 
LAMPLUGH : NOTES ON THE WHITE CHALK OF YORKSHIRE. 
As matters now stand, however, my attention has been directed 
to " fresh groves and pastures new," and 1 see no prospect of pur- 
suing this investigation further. Therefore it seems advisable that 1 
should in some rough form put forward my scattered observations for 
the use of workers more favourably placed for completing the study. 
In the present instalment I propose, as far as I am able, to 
discuss the thickness of the Chalk, an aspect of the subject which 
may at any time have an important practical bearing. In future 
communications I hope, on similar lines, to treat of the paleontology 
of the deposit ; of the conditions of accumulation as indicated by 
the state of the fossils ; and of some of the eftects of consolidation 
and of later earth-movements. 
I. The Thickness of the Chalk. 
It may truly be said that at present the Upper and Middle Chalk 
of Yorkshire is geologically little better than a desert province, whose 
boundaries have indeed been accurately detined, but whose interior 
is trackless and unexplored. Its monotonous sameness ; the paucity, 
except in a few localities, of its organic remains and the frequently 
unsatisfactory state of their preservation ; together with the isolated 
and limited character of its sections everywhere save on the sea coast, 
render exceptionally difficult the task of fixing and tracing horizons 
within it. For these reasons, since the eft'ect of the faults and dis- 
turbances which undoubtedly traverse the formation cannot be 
accurately determined, it is probable that in the interior of the East 
Riding the thickness of the Chalk will never be more than approxi- 
mately ascertainable, unless, of course, by deep boring. 
Therefore it is to the coast section that we must turn in search 
of more precise information. Even here, however, there are serious 
difficulties, by reason of the almost inaccessible position of some of 
the sections, and the interrupted character of others. Hence there 
have been remarkably few really serious attempts to measure these 
sections. Young and Bird* were content, with regard to the thick- 
ness of the Chalk, to state that it cannot be less in some places 
than 600 feet ;" Phillipst was equally indefinite, placing it at "not less 
* Young and Bird. Survey of the Yorkshire Coast (1822), p. 47. 
t Phillips J. Geology of the Yorkshire Coast, 3rd ed., p. 50. 
