Topley — Physical Geography of East Yorkshire. 435 



form alone, I am inclined to ascribe tliem to the " neolithic " rather 

 than to the " paleeolithic " period of India, whatever value these 

 terms may have when applied to that part of the globe. 



EXPLANATION OF PLATE XVI. 



Figs. 1-3. — Flint cores, or nuclei, discovered three feet beneath the bed of the river 

 Indus, near Shikarpoor, in Upper Scinde, by Lieut. Edward D'Oyly Twemlow, 

 of the Eoyal Bombay Engineers. (Two-thirds natural size.) 



Figs. 2a and 3a. — End-views, exhibiting the polygonal form of the nuclei. 



II. — Notes on the Physical Geography of East Yoekshike.^ 

 By William Topley, F.G.S., Geological Survey of Great Britain. 



THE district of Cleveland, long known for the beauty and variety 

 of its scenery, has during the past few years acquired great 

 importance through the discovery of valuable beds of iron ore in the 

 Middle Lias. So much has been written on this district, and in a 

 lesser degree on East Yorkshire generally, that the geological struc- 

 ture of this country must be tolerably well known.^ My object then 

 is not so much to describe the beds as to give some notes on the 

 physical geography of the country, explaining the relation of its 

 present surface outlines to its internal structure, and to enquire by 

 what means those external features have been produced. 



It may appear presumptuous on my part to attempt this after the 

 very able treatment the subject has received from Prof. Phillips in a 

 work devoted, in part, to this question.^ But I venture to think that 

 the origin of the present scenery of Yorkshire is due, in the main, to 

 subaerial denudation, not to marine action as stated by Prof. 

 Phillips. 



The characteristic features of Yorkshire are shown by a glance at 

 its river courses. These run in a general direction from the north 

 and west to the south and east. This is therefore the direction of the 

 general slope of the ground, and corresponds with the dip of the 

 beds beneath. The Vale of York, stretching uninterruptedly from 

 the Tees to the Humber, forms a well-marked boundary between 

 the Secondary rocks on the east and the Paleeozoic rocks on the 



1 Read before the British Association at Nottingham, August 24th, 1866. 



2 See especially — 



Young and Bird, Geological Survey of the Yorkshire Coast, 4to. 1822. 



Winch (N. J.) Observations on the Eastern parts of Yorkshire. Geol. Trans. 



2nd Series. Vol. V. p. 545. 

 Phillips (J.) Illustrations of the Geology of Yorkshire. 4to. Vol. I. 1829. 

 ,, Geological Map of Yorkshire. 1853. 



„ Manual of Geology. Ed. 1855. 



Quart. Journ. Geol. Soc. Vol. XIV. (1858) p. 84. 

 Marley (J.) Trans. N. of Eng. Inst, of Mining Engineers. Vol. V. (1857) 



p. 165. 

 Bewick (J.) The Cleveland Ironstone. 8vo. 1860. 

 Pratt (C.) Geologist for 1861, p. 81. 



^ Pavers, Mountains, and Sea Coast of Yorkshire. 8vo. 1853. 



