560 MR. E. WETHERFl) OX THE INFERIOR 



No. 2. The crystulliiie limestone above tlie " Sands.'' It yielded 

 only 9-9 per cent, of residue, which, like that from the previous bed, 

 contained quartz, tels])ar, occasional grains of zircon, some little 

 mica, and one fragment of tourmaline. 



No. 3. The Cepluilopoda-bed gave 31-1 per cent., made up chiefly 

 of some well-preserved felspar, a little zircon, and mica. Some of 

 the grains contained inclusions. 



No. 4. This 10-inch bed yielded 11' 1 per cent, of residue, con- 

 sisting of quartz associated with felspar and some zircon. 



No. 5. The 12 feet of irregular bedded material yielded 46-8 

 per cent, of insoluble residue, made up of quartz, felspar, and zircon. 

 Some of the felspars are remarkably well preserved. 



No. 6. The 10 feet of strata at the top of the Transition Series 

 yielded 42\S per cent, of residue, in which quartz predominates ; 

 felspar was present. This residue also contains flakes of a dark 

 granular substance, which proved to be coagulated silicate of alumina. 



The Pea- Grit Series. — The amount of residue in the beds of the 

 Pea-Grit Series (railway-cutting E. of Andoversford) shows a great 

 falling off compared with the Transition Beds. An estimation in a 

 typical specimen gave 2-1 per cent., a result which was quite consis- 

 tent with those obtained from corresponding beds in other localities. 

 The residue consists almost entirely of grains of quartz, averaging 

 0*17 mm. in greatest diameter. 



It will be remembered that the lowest exposure of the Pea-Grit 

 Series at the Horsepools is that of beds on the horizon of the Pea- 

 Grrit Series below the typical bed. A vertical section of these beds 

 has already been given on p. 554, and residues were obtained and 

 examined from the following : — 



Bed No. 2. Hard Brown Stone. Contains 4 per cent, of residue, 

 mostly quartz-grains, averaging 0*24 mm. in diameter. One frag- 

 ment of felspar was noticed. 



No. 3. Bastard Freestone. Yields 3*3 per cent, of quartz and 

 some mica. 



No. 4. lied Bed. Gives 102 per cent, of residue, mostly of well- 

 rounded quartz (PI. XX. fig. 5) as large as 0*49 mm. in diameter. 



A section showing the position of the beds of the Pea-Grit Series 

 in the Stroud area is given on p. 555. 



Two estimations of the quantity of residue in the 10 feet of free- 

 stone below the typical Pea Grit gave 7*5 and 4*9 per cent, re- 

 spectively. The freestone contains well-rounded grains of quartz, 

 averaging 0*17 mm. in diameter, one of which shows an inclusion, 

 apparently of rutile. Felspar is also noticed. 



The tyi)ical bed of Pea Grit yields 5*7 per cent, of residue, and 

 is remarkable for the large amount of cryptocrystalline silica which 

 it contains. This is in the form of casts (PI. XX. fig. 4) of organic 

 structures which occur in the rock. Putting aside these casts, the 

 detrital material appears to be remarkably small, and consists for 

 the most part of quartz, minute flakes of mica, and some felspar. 



Jied No. 3 gives 3*7 per cent, of residue consisting of quartz and 

 some zircons. 



