34 PROCEEDINGS OE THE COTTESWOLD CLUB 



That foraminifera were very numerous at times in the 

 (Carboniferous sea is of course well understood, but the 

 i^reat extent to which the tests of these microscopic 

 creatures contril)Uted to the calcareous ooze which 

 collected on the floor of the sea of this period has not 

 been fullv realised. It is of these minute shells that the 

 great central mass of. the Carboniferous Limestone in the 

 West of England and North Wales has been so to speak 

 constructed Fig. 2A. The only other organism which 

 can rival the foraminifera in this respect is the remarkable 

 and minute genus Calcisphcera which averages about '004 

 of an inch in diameter (Fig. 2B). This organism, so named 

 by Professor Williamson, F.R.S..* of Manchester, consists 

 of a hollow sphere of carbonate of lime, the interior of 

 which was apparently occupied by living matter. When 

 cut in section the Calcisphaerce have the appearance of 

 rings, in which form they are seen in Fig. 2 A and B. 

 In the former they are so minute that a magnifying glass 

 will probably be required to see them, but in Fig. 215 they 

 will be observed without difficulty. 



That the Calcisphaerae are organisms I think there is no 

 doubt, but whether they are to be referred to the animal 

 or vegetable kingdom is a matter yet to be decided. They 

 must have existed in Carboniferous waters in vast multi- 

 tudes, and their interest as limestone-forming organisms 

 has not been realized. So numerous were they that 1 

 question whether a fragment of Carboniferous Limestone 

 from the middle series of this formation could be examined 

 without finding several of them cither whole or in part. 



Another important incident attached to Calcisi)ha;ra 

 is that we have not found it to occur in any other rock 

 but that of the Carboniferous Limestone, hence its presence 

 is one way of determining this formation when doubt 

 arises. 



I'hil. Trans, vol, 171, pp. 520 525,1880. 



