1855.] 



PRESTWICH GRAVEL AT MAIDENHEAD. 



131 



TABLE OF ADMEASUREMENTS. 



Fossil. 



< 



Pallas, 

 in. lin. 



Breadth of the cranium between the orbital 



borders 11 4 



Greatest transverse diameter of the occiput ... 8 6 

 Vertical diameter of the occiput from the 

 middle of the super-occipital section to 

 the upper border of the foramen magnum 4 

 From the outer border of one occipital con- 

 dyle to that of the other 6 



Antero-posterior diameter of the base of the 



horn-core 9 



Length of the horn-core (following outer nerve) 



Depth of the intercornual groove 11 



Breadth of the intercornual groove 6 



.ubb 

 in. 



ock. 

 lin. 



Recent 

 old male . 

 in. lin. 



11 



7 



. 

 6 . 



.. 11 6 



..8 3 



3 



6 . 



..4 



5 



. 



..6 



7 



11 

 

 



. 

 . 



8 . 

 6 . 



.. 10 

 .. 12 6 

 .. 11 

 ..0 7 



2. Note on the Gravel near Maidenhead, in which the Skull 

 of the Musk Buffalo was found. By J. Prestwich, Esq., 

 F.R.S., F.G.S. 



The Valley of the Thames, broad and open in the tertiary area as far 

 as Maidenhead, there contracts into the comparatively narrow and 

 circuitous gorge through which the river traverses the chalk hills by 

 Henley, Reading, and Pangbourne. To this point also extends an 

 extensive mass of ochreous gravel, stretching in a continuous and un- 

 interrupted sheet from the sea to Maidenhead, a distance of 50 miles, 

 from 2 or 3 miles to 8 or 9 miles wide, and with a thickness of from 

 5 to 15 feet*. 



The great bulk of this gravel is composed of subangular chalk- 

 flints, derived, it may be presumed, from the destruction of portions of 

 the adjacent chalk-surface ; whilst, as subordinate materials, we find 

 a considerable number of perfectly rolled and round flint-pebbles, 

 derived directly, not from the chalk, but from the lower tertiary 

 strata and from the Bagshot sands ; also a not inconsiderable number 

 of hard quartzose sandstone-pebbles, pebbles of white quartz, slate, 

 and other older rocks,-— all perfectly rounded, — and these again 

 derived, not directly from the rocks to which they originally belonged, 

 but, as far as I can judge, all, without exception, from the conglo- 

 merates of the new red sandstone of Worcestershire and Warwickshire. 

 A singular feature of this gravel is, that although the transport of this 

 debris of the new red sandstone must have passed over the wide band 

 of the oolites of the midland counties, yet but extremely few traces 

 of these rocks are to be found. Of the Lower Greensand and sand of 

 the Portland series a number of the small black pebbles belonging to 



* It ranges much further westward, but forms narrower bands, or else detached 

 masses, and loses its distinctiveness. 



