Geologists’ Association. 139 
- 3. “On the Examination of Insoluble Residues obtained from the 
Carboniferous Limestone at Clifton.” By E. Wethered, Hsq., F.G.S. 
The author noticed previous classifications of the Carboniferous 
Limestone at Clifton, and submitted the following for reference in 
the present paper :— 
CARBONIFEROUS LIMESTONE SERIES. 
feet 
SiacenC HU ppermMsimestonesirececceactccscececscessoesecweresecctres ceases 100 
Middle nGimestonesieecreneceswesiersecesesisiaceccscccisallessio elses 1620 
», A. Lower Limestones :— 
MB ack vO CKiwirascicsk cslccaccecescscweenbeosete 490 
2. Lower-Limestone Shales.............s20000++ 500 
— 990 
Motallpcictskvaweesevcees 2710 
The limestone-forming organisms in each of the above were 
mentioned, and the methods adopted for obtaining the insoluble 
residues by means of hydrochloric acid were described. A table of 
percentages of insoluble residues was given from the Lower Lime- 
stone Shales and Black Rock, from the Oolitic Beds, Mitcheldeania- 
beds, and main portion of the Middle Limestones, and from the 
Upper Limestones. 
Detrital quartz of small size, with a few grains of felspar, tour- 
maline, and zircon, characterize the Lower-Limestone Shales, and in 
one variety the soft tissues of organisms are represented by ferric 
oxide, which in the case of crinoids represents the whole skeleton. 
Residues of the Black Rock exhibit slight secondary crystallization 
round detrital quartz, whilst amorphous and chalcedonic silica 
become more plentiful. Residues of the Middle Limestone consist 
to a less extent of detrital quartz along with micro-crystals of 
quartz, amorphous and chalcedonic silica, and less frequently of 
pyrites, tourmaline, and zircon; sponge-spicules are also noted. 
Towards the top of the Middle Limestones the proportion of detrital 
quartz increases, and the deposit of secondary silica on the surface of 
quartz-grains is less marked. 
’ The nature of the amorphous and chalcedonic silica in the lime- 
stone, and the relations of this silica to the small quartz-crystals, 
were also discussed. The latter were shown in some instances to 
possess nuclei of detrital quartz, and where this is not the case, to 
have resulted from the crystallization of amorphous silica. 
GeoLocists’ ASSOCIATION. 
December 2nd, 1887.—F. W. Rudler, Esq., F.G.8., President, in 
the Chair.—The following communication was read :— 
«A Synopsis of the Vertebrate Fossils of the English Chalk,” by 
A. Smith Woodward, F.G.S., F.Z.S. 
The author reviewed in succession the various genera of fossil 
vertebrata hitherto recorded from the English Chalk, adding full 
references to the literature of the subject, British and Foreign. A 
careful examination of the type-specimens and numerous other fossils 
in the British Museum, Brighton Museum (Willett Collection), 
