104 THE CANADIAN NATURALIST. [Vol. viii. 



ON THE MOLLUSCA OF THE POST-PLIOCENE 

 FORMATION IN ACADIA. 



By G. F. Matthew. 



[From the Annals of the Belgian Society of Malacology (SociSte - Malacologique 

 de Belgiciue, Tome IX, 1874.)] 



As an introduction to the immediate subject of this paper it 

 may not be out place to give a brief outline of the chief charac- 

 teristics of the Post-Pliocene Formation in the Northeastern part 

 of North America. 



Two writers, eminent both in America and Europe, have given 

 much time to the study of this formation. Dr. J. W. Dawson 

 in his writings on this subject, published in this Journal, and in a 

 synopsis entitled " Notes on the Post-Pliocene of Canada," Mon- 

 treal, 1872, gave a fnll account of the beds and of the organic 

 remains which they contain, in the Province of Quebec. Dr. 

 A. S. Packard of Salem, Massachusetts, has also devoted much 

 time to the study of Surface Geology, chiefly that of Labrador, 

 and of the State of Maine ; and has published the result, of his 

 observations in the Memoirs of the Boston Society of Natural 

 History, vol. I. part II. 



While these authors have discussed the phenomena of the 

 Post- Pliocene in the region to the west and north of Acadia, but 

 little attention has been given to this country itself. My object 

 in this puper is to supply this deficiency in part, by mentioning a 

 few facts bearing on the distribution of the Mollusca which the 

 Acadian beds contain ; both in relation to the depth of the sea 

 in which they flourished, and their geographical range now, as 

 compared with their distribution in Post-Pliocene times. 



The history of this period in North-eastern North America 

 opens with the movement of enormous masses of ice over the 

 face of the country from north to south. At every point where 

 the solid rocks are laid bare, deep and regular striae or scorings 

 attest the universality and great power of this attritive force. 

 Dr. Dawson holds to the theory that these gr oves, and the 

 " Boulder Ciay " which lies at the base of the surface depo- 

 sits, are due to the action of water-borne ice, carried southward 

 by a strong polar current ; while Dr. Packard boldly advocates 

 the view that the phenomena are due to the movement of a 



