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THE ALLUVIAL STRATA OF THE LOWER OUSE VALLEY. 
BY H. FRANKLIN PARSONS, M.D., F.G.S. (PLATE VIII.) 
It may seem as if something like an apology were needed 
for asking the West Riding Greological Society to leave the 
rocky dales of the Mountain Limestone, the wild hills and 
moorlands of the Millstone Grrit, and the mineral wealth of the 
Coal Measures, around which so much geologic interest centres, 
and to turn in imagination to a flat and tame district, where 
sections are few and far between, and fossils hardly to be 
found. Nevertheless a tyro like myself may with less pre- 
sumption hope to find something worth bringing before you 
in a region which seems to have been almost passed over by 
abler geologists, than in more attractive and better worked 
fields. I propose, moreover, to show that the district to 
which I refer is not without an interest of its own, for here 
we may read the last page of the earth's story, where geology 
merges into history, and may witness in progress changes 
which elsewhere we can only infer to have taken place. 
The district of which I speak is the low-lying level tract 
forming the southern part of the Yale of York, where the great 
tidal rivers Ouse, Wharfe, Derwent, Aire, Don, and Trent 
unite to form the Humber estuary, which then cuts its way 
towards the sea through the hills to the east. This broad 
plain occupies the space between the ranges of hills formed by 
the outcrops of the Chalk, Oolites, and Lias to the east, and of 
the Magnesian Limestone to the west. Beneath this area lie the 
Triassic rocks, the soft and friable nature of which has caused 
them to be eroded into this broad valle}^, while the harder 
rocks above and below stand out as ranges of hills. The 
Triassic rocks are for the most part covered up by the 
Quaternary Strata, but here and there they rise to the surface, 
forming low detached hills like islets, which, indeed, the 
