YORKSHIRE NATURALISTS AT KIRKBY MOORSIDE. 321 
The remarkable course of the Derwent—which, rising near the 
coast, flows westward instead of taking the valleys to the east—is 
a well-known instance of erratic river-flow, and points to an exten- 
sion of high land much further to the eastward in the early period of 
the formation of this vale. The whole of the drainage of this oval 
area is carried away by the Derwent through the gorge at Malton, 
and in the opinion of many observers this basin was once a lake or 
great sea-loch. : 
On either side of Kirkby Moorside a se sinuous valley 
Tuns northwards, cutting deep grooves into the table-like hills 
and exposing interesting sections of the Middle and Lower Oolitic 
beds, which dip gently to the south and are exposed in order as we 
pass northwards. The Lower Oolites, which in this area consist of 
a great series of estuarine, marine, and freshwater beds, are divided 
into three series, ‘each of which is capped by a thin but well-marked 
band full of marine fossils’ (Fox-Strangwayes), are exposed at the 
northern extremities of these valleys, but in their lower reaches the 
beds seen are confined to the Middle Oolites. It is to these that 
the attention of the Geological Section was principally directed. 
Immediately above the dark shales of the Cornbrash (the topmost 
bed of the Lower Oolites) comes the Kellaways rock, which in this _ 
area has a thickness of about 70 feet, and ‘is a tolerably massive 
sandstone which is ferruginous and fossiliferous in the upper part.’ 
Above this comes the Oxford Clay, which in this area is a grey, 
sandy shale, ‘lithologically very unlike its equivalent in the South 
of England,’ Its fossils are few in number and badly preserved. 
The Lower Calcareous Grit, about 150 feet in thickness, in this 
area consists of a massive sandstone which passes gradually into the 
_ Oxford Clay beneath, and becomes ‘more calcareous in its upper 
part until it passes into the true limestone above.’ Above this come 
the Passage Beds, which in this area lose much of the distinctness _ 
which characterises them more to the east, and are ‘ less ferruginous 
and rather more massive in character.’ The capping rock of a great 
thick-bedded limestone ‘ composed 
part of the tabular hill above Kirkby is the Coralline Oolite, a massive _ 
- @ great number of ee This: limestone is divided into two 
principal beds, separated by a set of sand the Middle 
 Calcareous Grit. Kirkby Moorside itself stands on the Upper — 
_ Calcareous Grit, whilst the rising ground immediately above the - 
town, to east, west, and south, is capped by blue Kimeridge Clay. — 
- This clay is supposed to underly the greater part of the alluvial and 
of minute oolitic grains with 
c — beds ee Vale ar despot bars is sai Asttagrinege in ee 
