Geological Society of Glasgotv. So 



terized by its large size and pyramidal shape, and by its interior 

 being quite hollow, except at the apex ; whereas in the other genera 

 of fossil Plagiostomes the spines are narrow, gradually tapering, 

 solid, and in many cases furnished with one or more rows of den- 

 ticles. Oracantlms is further distinguished by the blunt tubercles 

 which, either singly or in ridges, cover its surface. 



The President also exhibited a new icthyodorulite, sent by Mr. 

 Kobert Craig (a Corresponding member), from Langside Quarry, 

 near Beith. 



Mr. John D. Campbell exhibited some specimens of wood en- 

 crusted with oxide of iron from the head of Loch Melfort, Argyll- 

 shire. In the same section fragments of wood and hazel-nuts in a 

 good state of preservation were found, showing that the incrustation 

 of the specimens exhibited was due to local oozing of water charged 

 with iron. 



The following papers were then read : — 



1. " On the section of strata at present being worked in the 

 western portion of the Gilmorehill grounds, for the purpose of 

 obtaining Building Stone, for the erection of the new University." 

 By Mr. John Young. — The paper was illustrated by specimens of 

 the sandstone, etc., and by vertical and horizontal sections of the 

 strata in the quarry. The chief interest to a geologist in this quarry 

 consists in the numerous strata therein exposed, there being no fewer 

 than twenty-six different beds in the depth of sixty feet from the 

 surface. These consist of five seams of free coal, varying in thick- 

 ness from nine to eighteen inches : five beds of sandstone, with 

 accompanying strata of clay shale, bituminous shale, fireclay, and a 

 thin seam of blackband ironstone. The geological position of the 

 strata is in what is known in the Glasgow district as the Possil 

 Lower Coal and Ironstone series, which lies about 510 fathoms under 

 the Upper Eed Sandstone of the Lanarkshire Coalfield. Mr. Young 

 next pointed out the relation which the Possil series bears to the 

 strata of other portions of the Scottish Coalfield, and stated that 

 they occupy a middle position in the Carboniferous Limestone series 

 of this country ; yet in this district, throughout a thickness of 900 

 feet, no limestone band or other calcareous strata are found. Their 

 lithological character, and the nature of the organic remains, present 

 us with conditions very similar to that which prevailed during the 

 deposition of the sedimentary strata of the Upper Coal-measures of 

 Western Scotland. 



The sandstone of the Gilmorehill quarry is a whitish fine-grained 

 rock, streaked at intervals with carbonaceous matter. It occurs in 

 beds, the thickest of which is fully 12 feet. The five beds in the 

 quarry will yield about 40 feet in thickness of good serviceable rock. 



During the working of the uppermost part of sandstone in the 

 quarry, the workmen came upon the remains of the stumps of five 

 large fossil trees standing in an erect position, with their roots 

 extending into the bed of shale upon which they once grew. They 

 belong to the genus Sigillaria, and while they were allowed to remain 

 in position they formed a very interesting object in the quarry. 



