566 MR. E. "VNETHEEED ON THE INFERIOR 



from crystalline felspathic rocks, and not from the denudation of 

 stratified ones. The quantity of felspar and its state of preservation 

 seem to support this view. 



(d) Tlie Quantity of Residue and Size of the Quartz-cfrains. 



When descrihiug the respective residues I have generally stated 

 the quantity existing in the rock, but as this is an interesting and 

 important point I propose to refer to it in greater detail. The 

 following table gives the percentage of residue and average of quartz- 

 grains in the Transition Beds : — 



Percentage of Average size 

 Insoluble of Quartz- 

 Residue, grains in mm. 

 The topmost 10 feet of the Calcareous Argilla- 

 ceous Beds 42-8 0-16 



Irregularly bedded argillaceous material 46"8 0'17 



10-inch Calcareous Bed ll'l 0"16 



Cepbalopoda-bed 3M O'll 



Crystalline Limestone 9'9 0*10 



Midford Sands 880 009 



The residues show a falling-off in quantity above the Midford 

 k^ands, a feature much more marked in the Pea-Grit Series, which 

 iollows the Transition Beds. 



The following table gives the residue and size of quartz-grains in 

 the Pea-Grit Series in the localities referred to in this paper : — 



Percentage of Average size 

 Insoluble of Quartz- 

 East of Andoversford. Residue. grains in imm. 



I.Limestone 2*2 0-06 



n. „ Pisolitic 3-8 0-16 



in. „ Coarse Oolite 21 017 



Horsepools District. 



IV. Hard Brown Stone 4-0 0-24 



V. Bastard Freestone 3-3 020 



VI. Red Bed (lowest exposed) 10-0 0-20 



Stroud District. 



VILBedNo. 6 17 013 



VITI. „ „ 5, argillaceous 24 '5 0-13 



IX. „ „ 4 4-6 012 



X. „ „ 3 3-7 0-11 



XL „ „ 2, typical Pea Grit &1 0-18 



XIL „ „ 1b 4-7 0-17 



XIIL „ „ lA 7-5 017 



Clccve Hill. 



XIV. Bed No. 24, arenaceous 8*0 0-11 



XV. „ „ 20 1-1 0-15 



XVL „ „ 19, typical Pea Grit 36 017 



XVIL „ „ 17 0-6 0-15 



XVIIL „ „ 15 4-0 0-07 



XIX. „ „ 11 1-2 — 



XX. „ „ 3 5-5 006 



