NATURAL HISTORY SOCIETY OF GLASGOW. 125 



the ocean might prove to be on a large scale what the Dead Sea 

 was on a small one. Dr Young next referred to the occurrence of 

 coal of cretaceous age in the far north, and the bearing of this fact 

 on the possible change of the earth's axis of rotation. He spoke 

 of Nordenskiold's and Judd's objections to the current doctrine of 

 a glacial epoch and polar ice-caps, and of Professor Ramsay's 

 caution against exaggerating the importance of glacial deposits 

 and treating them as of equal value with the Silurian or Carboni- 

 ferous strata ; lastly, he referred to the distribution of the man- 

 ganiferous deposits as sliown by Mr Murray, but left it to Mr 

 Young to discuss this point in reference to the limestone at 

 Cunningham Bedland, which Mr Young had got analyzed. 



SPECIMENS EXHIBITED. 



Dr Young exhibited the type specimens of Ellis and Solander's 

 corals, which, to the number of nineteen, he had identified in the 

 Hunterian Museum ; also a case of Bohemian trilobites received 

 from Dr A. Fritsch. 



Mr John Young, F.G.S., exhibited specimens of a small re- 

 ticulated sponge found by Mr James Armstrong, of the Glasgow 

 Geological Society, in the same deposit of rotted Carboniferous 

 limestone at Cunningham Bedland, near Dairy, in which the 

 sponge spicules, Acanfhosjyongia Smithii, exhibited at a former 

 meeting, were obtained. Mr Young stated that it was of interest 

 to know that, besides the occurrence of siliceous sponges in this 

 deposit, there was the evidence of the presence of sponges belong- 

 ing to other groups in the same family. Mr Young also exhibited 

 a sample of the peculiar reddish-brown mud in which the sponges 

 and other organisms are found. This mud is the inorganic residue 

 of the limestone left in the eroded fissures of the rock through the 

 action of water charged with carbonic acid. From its resemblance 

 in colour to the manganiferous mud found by the Challenger 

 expedition over certain of the deeper parts of the sea bottom, it 

 had occurred to Mr Young that this residue of the rotted limestone 

 might also contain manganese, and he therefore had a small 

 quantity tested at the laboratory of Glasgow University, when it 

 was found that the mud, when fused with carbonate of soda, gave 

 a decided greenish tinge, forming a manganite of soda. No 

 quantitive analysis of the amount of manganese in the mud had 

 been made, but it was thought that there could not be less than 



