972 



SCIENCE. 



[N. S. VoL.XXIII. No. COO. 



upon the surface, afford unusual facilities 

 for the study of rock plaster in all its 

 varied forms, and for the consideration of 

 the theories which have been proposed to 

 account for the origin of the latter. One 

 of these theories, strongly advocated by Sir 

 William Dawson, supposed the gypsum to 

 result from the reaction of sulphuric acid, 

 an indirect product of volcanic action, 

 upon limestone; while a second supposes 

 the same product to have resulted from 

 direct precipitation from sea water in shal- 

 low land-locked basins, under conditions of 

 high temperature and aridity. While the 

 latter view, based on observations of in- 

 land salt sea, like those of Utah, is now 

 generally accepted, much diversity of opin- 

 ion still exists as to the separate origina- 

 tion of gypsiim and anhydrite, some main- 

 taining the former and some the latter to 

 have been the original and antecedent rock, 

 while still others suppose that either or 

 both may be deposited from the same solu- 

 tion, according to varying conditions of 

 temperature, depth of water, presence of 

 saline salts, etc. It is the purpose of the 

 present paper to consider some of these 

 views, and especially such as relate to the 

 occurrence and origin of gypsum and 

 anhydrite (soft and hard plaster) in the 

 light of observations recently made by the 

 author in the Hillsboro quarries, with in- 

 cidental references to those found else- 

 where in the province. 



'Features of the Continental Shelf off 

 Nova Scotia,' by Dr. H. S. Poole. 



This paper treats of the preglaeial drain- 

 age when the countrj^ was much elevated, 

 wh'ere the mouth of the ancient St. Law- 

 rence River was one hundred miles east- 

 ward of Cape Breton, theorizes on the 

 origin of the Strait of Canseai;, and sug- 

 gests that the ice sheet extended Avell be- 

 yond the present shore line. 



'Notes on Tertiary and Cretaceous 

 Plants,' by Professor D. P. Penhallow. 



The basis of the present paper is found 

 in several collections of plants from local- 

 ities in British Columbia, placed in the au- 

 thor's hands by the geological survey for 

 determination in the spring of 1905. Only 

 the names of the identified species have so 

 far been reported, and as it seems desirable 

 that some of them should be dealt Avith 

 more in detail, and the correlation of geo- 

 logical horizons indicated, they are now de- 

 scribed at length. It is shown in connec- 

 tion with more recent studies that both the 

 Tertiary and the Cretaceous forms may 

 be definitely correlated with previously 

 known floras, and that they are chiefly of 

 Oligocene and Shasta-Chico age, respect- 

 ively. 



The author also directs attention to some 

 recently studied material from the Pleisto- 

 cene of Elmira, New York. This material 

 consists of two specimens of the common 

 white elm, and one specimen of a maple 

 which can not be correlated with any ex- 

 isting species. It is, therefore, designated 

 as Acer neivtoivnianum in reference to the 

 Newtown Creek, in the gravel banks of 

 Avhich the woods were found. Attention 

 is directed to the occurrence of leaves of 

 Acer pleistocenicum Penh., in the Pleisto- 

 cene clays of the Don Valley, and the pos- 

 sible connection between the extinct species 

 represented by wood, and the one now 

 represented wholly by leaves, is pointed 

 out. 



'Review of the Flora of the Little River 

 Group, Part I., the Calamaria?,' by Dr. G. 

 F. Matthew. 



The writer will give in this paper and 

 later ones, the result of the revision of the 

 plant remains, studied and described by 

 the late Sir William J. Dawson,, that were 

 found in plant-bearing strata in and near 

 St. John, N. B., Canada. In this examina- 

 tion Avill be embodied the revision of the 

 types of this flora returned by Sir William 

 to the Natural History Society of New 



