president's address. 205 



visited by many of the members, who were obligingly shewn 

 over the quarry, through the kind permission of Mr. John Dag- 

 lish, by the intelligent foreman. The bed of limestone quarried 

 belongs to the lower part of the Upper-series of the Magnesian- 

 limestone formation. It is obtained in very large blocks, and is 

 suitable for pier works and other building and economic pur- 

 poses, and from its being a nearly pure carbonate of lime (98'38 

 per cent.), and containing only a trace of carb. magnesia (1*25 

 per cent.), is much used for chemical purposes and for burning 

 into lime. Only a few fossils occur in this bed, as the character- 

 istic bivalve Axinus dulius, which occurs of large size, and 

 generally with the valves open ; Myalina Hausmanni, also large, 

 and more rarely Pleurophorus costatus. In some of the associated 

 beds these shells form the centre of a globular radiating concre- 

 tion, and are often so perfectly preserved that they can be easily 

 removed from the central cavity. 



The Presidential chair of your Society has usually been filled 

 by specialists in some branch of Natural History, and those 

 eminent scientists have often concluded their address by giving 

 the results of their own personal observations, as bearing on 

 some particular department of study. I will not attempt to 

 follow them in this, but, by the kindness of several members and 

 friends, I have been able to incorporate with this Address several 

 valuable papers, namely: — On " The Stump- Cross Cavern" by 

 Dr. Embleton ; " A List of the Plants and Insects collected during 

 our last Field day ;" " Notes on the Puccinia Graminis" by Signor 

 Batalha-Reis ; and the following Note on " A Rare Lichen 

 Lecidea diacapsis" by Rev. "W. Johnson. 



"Lichenes: Lecidea diacapsis (Ach.), Johnson. — In going over 

 and re-naming Mr. "Winch's Lichens, in the B arras Bridge 

 Museum, I found two specimens called Urceolaria diacapsis, Ach. 

 (see my note in list of Winch's Lichens). Dr. Nylander, Paris, 

 has examined one of the specimens, and confirms my diagnosis, 

 and accepts the name I suggested, and which I have placed at 

 the head of this note. In a second note, Dr. Nylander urges me 

 to try and find this lichen in its habitat, which I shall endeavour 



