Vol. 59.] FOSSIL FLORA OF THE CUMBERLAND COALFIELD. 17 



the Series may probably be divided into two divisions ; but the 

 discovery of $/nYor&is-Limestone did not, as will be shown here, 

 frx the horizon of the Upper Division .beyond doubt. As the boring 

 in question must be referred to in some detail, it may be well 

 to give a condensed account of its principal features, taken from the 

 table in Mr. Brockbank's paper. 1 



Thickness. Depth below 



surface. 

 Feet inches. Feet inches. 



3. Permian Breccia 20 42 



2. Red and purple sandstones, shales, and 

 conglomerates, with two thin bands of 

 Spirorbis-Tiimestone, and three thin bands 



ofcoal ...: 418 8 460 8 



1. Red and purple sandstones, shales, and 



conglomerates 112 7 573 3 



Boring ended. 



The occurrence of 20 feet of Permian Breccia, above the Spirorbis- 

 Limestone, shows that in all probability the whole of the upper 

 part of the Sandstone Series is present here. Mr. Brockbank was 

 of opinion that, at a depth of roughly 420 feet below the Permian, 

 or 214 feet below the lower band of Spirorbis-IAmPstone, the sand- 

 stones presented a similar appearance to those at Whitehaven. If 

 the lower 112 feet is thus correctly identified, then he says 2 ' they 

 thus become Middle Coal-Measure sandstones beyond doubt.' 

 There is no evidence that, even at 573 feet, when the boring ended, 

 the basal beds of the Sandstone Series had been reached. Indeed, 

 if we remember that this series in Bransty Cliff, near Whitehaven, 

 is at least 170 feet thick, 3 and has there been largely denuded, it is 

 probable that the bore only passed through a portion of the full 

 extent of the Lower Division of the Sandstone Series. 



(1) Upper Division, Sandstone Series. 



The only palseontological evidence, as to the horizon of the Upper 

 Division of the Sandstone Series, is the occurrence of the two bands of 

 Sptirorbis-JAmestoue. The value of Spirorbis, as marking a particular 

 zone in the Coal-Measures, is, however, becoming smaller every year, 

 in view of the wide vertical range which this fossil has been proved 

 to possess in certain districts. This is particularly the case in the 

 Upper Carboniferous rocks of North Staffordshire, as Mr. Walcot 

 Gibson 4 has recently shown. Mr. Kiclston tells me that he has 

 also found that the occurrence of Spirorbis does not agree with the 

 evidence of fossil plants in other districts. If, therefore, the occur- 

 rence of Spirorbis at Frizington Hall can be regarded as of any 

 value at all, it probably points to the Upper Division of the Sand- 

 stone Series as belonging to the Transition Coal-Measures, an horizon 



1 W. Brockbank (91) p. 418. 



2 Ibid. p. 420. 



3 J. D. Kendall (96) p. 202. 



4 W. Gibson (01) p. 253. 



Q.J.G.S. No. 233. c 



