PBOCEEDINGS OF GEOLOGICAL SOCIETIES. 



225 



Nova Scotia." By the Rev. D. Honeyman. — A careful examination of 

 the country in the neighbourhood of Arisaig enabled the author to con- 

 struct three sections and a map, showing the geological constitution of 

 the district. Two of these sections were nearly parallel to one an- 

 other, running from north to south, and taken some distance apart, 

 while the third was nearly at right angles to the other two ; thus a 

 tolerably accurate idea of the geology of the country could be ob- 

 tained. The author described each of these sections in detail, giving lists 

 of the fossils found in the different beds, which proved them to be of 

 Upper Silurian age ; and he further considered that they justified the 

 adoption for the subdivisions of these Nova-Scotian Silurians of the 

 terms May-hill, Lower Ludlow, Aymestry, and Tilestones, the first and 

 third of which had been used for them previously by Mr. Salter. Besides 

 Silurian rocks, there occurs in the western part of this district a conglo- 

 merate of Lower Carboniferous age, while trap-rocks occur on the north 

 and south. 



2. " On some Remains of Fish from the 4 Upper Limestone ' of the Per- 

 mian Series of Durham." By Mr. J. W. Zirkby — The object of this 

 paper was to record the discovery of fish-remains in the upper mag- 

 nesian limestone of the Permian formation, which is higher in that 

 series than any vertebrate remains had been previously known to occur. 

 The strata exposed in the quarries were described in detail, especially 

 the bed from which most of the fish were obtained, and which is known 

 as the " flexible limestone." 



The author stated that at least nine-tenths of the specimens belong to 

 JPalcEoniscus varians, the remainder belonging to two or three species of 

 the same genus, and to a species of Acrolepis. Detailed descriptions of 

 the different species of fish were given, as also were short notices of the 

 species of plants sometimes found associated with them, one of which he 

 believed to be Catamites arenaceus, a Triassic species. The occurrence of 

 Pal(Bonisci with smooth scales was stated to be antagonistic to Agassiz's 

 conclusion, that the Permian species of that genus have striated, and the 

 Coal-measure species smooth scales. In conclusion, Mr. Kirkby remarked 

 that the fauna of the period appeared to have an Estuarine facies, and he 

 expressed his opinion that the fishes were imbedded suddenly, as a result 

 of some general catastrophe. 



3. "On the Fossil Corals of the West Indian Islands. Part 3 : Mineral 

 Condition." By P. Martin Duncan, M.B.— The results of the process of 

 fossilization, as seen in the West Indian fossil corals, being very remark- 

 able, and having much obscured their specific characters, thus rendering 

 their determination extremely difficult, Dr. Duncan found it necessary to 

 thoroughly examine their different varieties of mineralization, and to com- 

 pare their present condition with the different stages in the decay and 

 fossilization of recent corals as now seen in progress. Thus the author 

 was enabled to show the connection between the destruction of the mi- 

 nuter structures of the coral by decomposing membrane and certain forms 

 of fossilization in which those structures are imperfectly preserved ; and he 

 likewise stated that the filling-up of the interspaces by granular carbonate 

 of lime and other substances, as well as the induration of certain species, 

 during a "pre-fossil" and "post-mortem" period, gave rise to certain va- 

 rieties of fossilization, and that the results of those operations were perpe- 

 tuated in a fossil state. 



The forms of mineralization described by Dr. Duncan are — Calcareous ; 

 Siliceous ; Siliceous and Crystalline ; Siliceous and Destructive ; Siliceous 



VOL. VII. 



