108 NATURAL HISTOKY SOCIETY OF DUBLIN. 



Mr. Archer referred to Dr. E. "W. Smith's record of both S. Tun- 

 bridgense and R. Wilsoni near Sir A. Brooke's seat, in the county of Fer- 

 managh, in 1860, in the "Proceedings" of this Society, remarking 

 that this came in to help to complete the chain of westward distribu- 

 tion. 



Mr. Good, judging from bis experience of the distribution of marine 

 animal life, and arguing from analogy, would suggest that probably the 

 geological formation had even more to do with the distribution of various 

 species of plants ; he had obtained the oxhorn cockle, and Norway 

 lobster off Helvick Head, county of Waterford. 



The Kev. Dr. Haughton considered Mr. Good's suggestion well worth 

 attention. While peculiarities of climate were doubtless very impor- 

 tant, the conditions of soil were also very influential in regulating the 

 distribution of forms of life, more especially of plants. At Lizard 

 Point, in Cornwall, this had forcibly struck him. There the soil was 

 serpentine, containing silicate of magnesia; and some of the common 

 species of plants of the locality had arrested his attention by their pecu- 

 liarities, whilst the same species were not, perhaps, to be found many 

 miles from their own limited district. Again, often from the chemical 

 composition of a rock can be predicted the kind of fossils to be found 

 in it. Dr. Haughton referred to the foxglove, which, as is well known, 

 avoids the limestone ; and as to Mr. Foot's statement in a previous com- 

 munication, that he had' found it on that formation, he (Dr. Haughton) 

 believed that Mr. Foot had modified his opinion as to its being found 

 on pure limestone. Some considered it to be restricted to certain limits 

 as regards the sea level, but it so happened that that often coincided 

 with the limestone. 



Mr. Foot stated that the foxglove alluded to by him had been found 

 on argillaceous limestone. Heaths, too, dislike pure limestone ; and 

 wherever they occurred on limestone, one might always look for siliceous 

 beds. In Cornwall, Erica vagans grows on serpentine, and one might 

 draw a geological boundary by tracing that of the heath. 



Dr. Moore considered the plants which had been mentioned— Digi- 

 talis purpurea and Erica vagans— as the two most " geological " in 

 their tendencies ; and whilst some might show certain predilections, he 

 did not know of others which were at all strictly so. He had seen, in 

 the county of Antrim, where varieties of soil occurred, the foxglove 

 close to limestone, growing in a debris of other rocks, but never in pure 

 limestone. In regard to the heath, all the Ericaceae disliked limestone ;^ 

 he might especially instance Rhododendron, which died therein, as if 

 poisoned. 



Mr. E. L. Edgeworth, as the attention of the meeting had been directed 

 to Ferns, took the opportunity to place on record the discovery in the 

 county of Longford of Pohjstichum lonchitis (Eoth) ( = Aspidium lon- 

 chitis, Swartz et auct.). Contrary to previous experience, this plant 

 had been found on the road side, under an old hedge, growing between 

 loose stones. 



