312 THE CANADIAN NATURALIST. [Vol. ix. 



fragile shells, as Helix chersensis and Vitrmu Iwiplda are fully 

 equal in size. 



In presentinir the list the Principal remarked it is of interest 

 as including species which may have crossed into Prince Edward 

 Island in the later continental period succeeding the glacial sub- 

 sidence, or have passed across Northumberland Strait on floating 

 timber or by means of migratory birds. 



It is to be observed that while Prince Edward Island is rich 

 in vegetation, it has less variety in point of stations for land 

 snails and in exposures of calcareous rocks than neighbouring 

 parts of the mainland. 



The President then read a lengthy paper entitled " Further 

 reniarks on the Stratigraphy of the Quebec Group." This was 

 a reply to Mr. Thos. Macfarlane, who in an article published in 

 our issue of June 23rd, 1879, had criticised a former paper by 

 Mr. Selwyn. The paper forcibly presented the author's views 

 to the effect that certain crystalline rocks known as diorites, 

 dolerites, and amygdaloids, were of volcanic origin, as was shewn 

 by their physical and mineralogical characters as well as by their 

 microscopic structure. 



Prof. Hitchcock, Director of the State Geological Survey of 

 New Hampshire, being present said a few words on the subject 

 discussed by Mr. Selwyn, expressing the hope that he might 

 have an opportunity of studying this Quebec Group in the light 

 of the views set forth. 



Dr. T. Sterry Hunt followed in a speech of close reasoning, in 

 which he assailed the views of the last generation, which sup- 

 ported Mr. Selwyn's position. He said what they had listened 

 to that evening was a re-statement of an old theory built up by 

 the Murchison, Lyell and Sedgwick school, eminent men in their 

 own special field of study, but since their time a generation of 

 geologists had appeared, who, qualified by a more comprehen- 

 sive knowledge of mineralogy, microscopy, chemistry and lithol- 

 ogy, had come to the conclusion that the rocks claimed as volcanic 

 were not so. He was supported in the view he held by the 

 ablest geologists of Europe, and the leading scientists of England 

 were entirely of this view. 



Dr. Dawson held that there was not sufficient evidence to 

 prove these rocks volcanic. He had suggested the term aqueo- 

 igneous as the best description of the cause of their formation. 



