Vol. 62.] IN THE CANNOCK-CHASE DISTRICT. 529 



Cannock Chase. At the last-named a thickness of only a few feet represents the 

 whole of the Carboniferous Limestone of the Midlands, and the fossils distinctly 

 point to the fact that the fauna found by the Author represents the very 

 highest beds of the Carboniferous Limestone of the Midlands. The coral-fauna 

 (Amplexizaphrentis) is found in the upper part of the Upper Dibunophyllum- 

 Zone of Vaughan. The presence of Productus giganteus with the corals makes 

 the horizon absolutely definite. Attenuation of the Carboniferous Limestone to 

 the south has therefore taken place at the expense of the lower beds, which 

 gives important evidence as to the physiography of that period. Farther south 

 the Coal-Measures rest directly upon Silurian rocks, the whole of the Lower 

 Carboniferous Series being absent in South Staffordshire. I congratulate 

 the Author on his valuable paper.' 



Mr. Walcot Gibson referred to the occurrence of Carboniferous 

 Limestone at Lilleshall and at the northern end of the Leicester- 

 shire Coalfield, and also in a boring at Kettering Eoad near 

 Northampton. Over the Warwickshire and South-Staffordshire Coal- 

 fields its absence was well known, With reference to the presence 

 of Carboniferous Limestone in the Fair-Oak trial-shafts, it was 

 interesting to find that pebbles of Carboniferous Limestone are 

 common in the conglomerates of the Upper Coal-Measures and 

 so-called ' Lower Permian ' of the Severn Valley ; while they are 

 rare or are absent from these conglomerates in Warwickshire. It 

 is, therefore, certain 'that the Carboniferous Limestone was being 

 denuded during the later stages of the Coal-Measure Period. The 

 limestone at Fair Oak would furnish one probable source for the 

 pebbles in the conglomerates of the Upper Coal-Measures of the 

 Severn Valley. 



Prof. W r ATTs referred to the dolomitization of the Carboniferous 

 Limestones north of Charnwood Forest; and asked whether the 

 limestone of Fair Oak was in a dolomitic condition. 



The Author remarked that but little reply seemed necessary. 

 No samples of Silurian limestone had been left at Cannock-Chase 

 Colliery No. 2, but there was very little doubt that such limestone 

 had been found there. 



