OOLITE OK TJIM COTT KSWOLD HILLS. 5Gi 



Ikul No. 5 yields 4'() per cent, of residue consisting of quartz, 

 i'elspiir, and small Hakes of mica. 



lied No. yields 1*7 per cent, of quartz, with some felspar, 

 zircon, mica, and a little cryptocrystallino silica. 



For the heds selected tor examination at Cleeve Hill, sec the 

 vertical section of the Pea-Grit Series on p. 550. 



Bed No. 5 yields 5*5 per cent, of residue made up of quartz, 

 flakes of mica, silicate of alumina, cryptocrystalline silica, and a 

 number of microscopic quartz-crystals with sharply defined faces 

 (PI. XX. hg. ()). They appear in the form of prisms capped by 

 pyramids and contain numerous inclusions. The crystals seem to 

 liave originated from the cryptocrystalline silica and silicate of 

 alumina, and the inclusions in the cr3\stals appear to be portions of 

 the latter substance. There are also other crystals present of a 

 very different origin. These are reconstructions around an original 

 crystal of quartz, the faces of which have been worn off apparently 

 by water-action. These forms are similar to those I have described 

 and figured * from the Carboniferous Limestone of Clifton, near 

 Bristol. 



This residue also included some free detrital quartz-grains with 

 an average diameter of 0-1 (5 mm.; in one instance an inclusion of 

 zircon was noticed. 



No. G. This bed gives 0*4 per cent, of residue, mainly of detrital 

 quartz, with some felspar and zircon. 



No. 15. This typical Pea Grit contains a residue of quartz, small 

 scales of silicate of alumina, and some felspar. A comparison with 

 the residue obtained from the typical bed at Stroud shows that the 

 cryptocrystalline silica, so prominent a feature in that residue (see 

 p. 5(50), does not occur in this. 



Bed No. 17 yields 0*G per cent, of residue, in which quartz, 

 felspar, and zircon are the chief constituents. 



Bed No. 19. This is the second bed of typical Pea Grit. It has 

 l)'6 per cent, of residue, which corresponds with that from the bed 

 at Stroud in the quantity of casts of cryptocrystalline silica it 

 contains. The residue also shows quartz and well-preserved felspar. 



Bed No. 20 yields 0*2 per cent, of residue, of which quartz-grains, 

 with some felspar, rutile, and zircon, are the chief constituents. 



Bed No. 24. This is a sandy bed. It gave 8 per cent, of residue, 

 chiefly quartz. 



The Lower Freestone. — As before remarked, I regard the Polyzoa 

 Bed at Cleeve Hill and the Lower Coral Bed in the Southern Cottes- 

 wolds as the base of the Lower Preestone. 



At Cleeve Hill the Polyzoa Bed contains 3 per cent, of residue, 

 chiefly detrital quartz-grains as large as 0*3 mm. in their longest 

 diameter, but averaging about 0-22 mm. AVell-preserved fragments 

 of felspar, including microeline, are also present. 



The Coral Bed at Crickley Hill, near Gloucester, gave 3-2 per 

 cent, of residue, consisting of quartz, felspar, and rutile (?). 



* Quart. Jouni. Geol. Soc. vol. xliv. (1888) pi. viii. figs. 3 & 4. 



