Montreal Natural History Society. 223 



Canadian Geological Survey), relating the exact circumstances under 

 which the specimen to be described was found, and giving a detailed 

 description of a section of the rocks from which the fossil in question 

 was procured. 



Principal Dawson exhibited a photograph of a remarkable specimen 

 of Eozoon Canadense, found during the past summer in the Lauren- 

 tian limestone of Tudor, Canada West, by Mr. Vennor. The rocks at 

 Tudor and its vicinity, which, according to the observations of Mr. 

 Vennor, are Lower Laurentian, have experienced less metamorphism 

 than is usual in formations of that age. And this peculiarity gives 

 especial interest to the present specimen, which is contained in a rock 

 scarcely altered, and in a condition not essentially different, from 

 that of ordinary Silurian fossils. 



The matrix is a coarse laminated limestone of a dark colour, and 

 containing much sand and finely comminuted carbonaceous matter. 

 The fossil itself is of a flattened clavate form, about six and a half 

 inches in length, and with the septa of its chambers perfectly pre- 

 served, exhibiting on one side a well-defined marginal wall, pro- 

 duced by coalescence of the septa, and apparently traversed by 

 small orifices. Under the microscope the minute structures of 

 Eozoon Canadense can be detected, though less distinctly perceived 

 than in some of the specimens mineralized by serpentine. In some 

 of the chambers there are small amorphous bodies containing pointed 

 silicious spicules, which seem to be the remains of sponges that have 

 established themselves in the cells after the animal matter of Eozoon 

 had disappeared. 



The importance of this specimen was pointed out as establishing 

 the conclusions previously arrived at from the study of the remains 

 of Eozoon included in the serpentinous limestones, and as overthrow- 

 ing the objections raised in some quarters to the organic origin of 

 Eozoon. The specimen will be taken to England by Sir W. E, Logan, 

 and full details of its characters will be communicated to the Geolo- 

 gical Society, along with some other recent discoveries, tending to 

 the establishment of a second species of Eozoon. 



Dr. Hunt, in some remarks made at the conclusion of the paper, 

 gave Mr. Vennor due credit for establishing the occurrence of 

 Laurentian limestones at Tudor, and stated that the degree of meta- 

 morphism of rocks was not necessarily dependent upon the age of the 

 formation. 



III. — One of the course of six free lectures annually given by the 

 Natural History Society, was delivered on February 9th, by Dr. T. 

 Sterry Hunt, F.E.S., President of the Society, to a full and attentive 

 house. 



The subject announced was " The Origin of Continents." The 

 lecturer proceeded to describe briefly the great facts with regard to 

 the outlines of continents and oceans. The mean depth of the 

 waters, which cover eight-elevenths of the globe, was about 10,000 

 feet, and the mean height of the land about 1,000 feet. If we suppose 

 a globe eighty feet in diameter, the deepest parts of the sea would be 



