JVernerian Natural Histonj Society. 239 



WERNERIAN NATURAL HISTORY SOCIETV. 



At the meeting of this Society on the isth of Jaunary, 

 Professor Jameson read a paper on porphyry, in which he 

 described several species of transition-porphyry, as occur- 

 ring along with grey-wacke, &c. in different parts of Scot- 

 land. He also gave a particular account of ficElz porphyry, 

 which likewise occurs in Scotland, and appears to belong 

 to ihe old red sar.dslone formation. The Professor conjec- 

 tured that this floetz porphyry may be the mother-stone of 

 the porphyritic felspar lavas which are found in some coun- 

 tries, and consequently that lavas may occur in rocks of an 

 older date than those of the newest flcetz-trap scries. — At 

 the same meeting, Mr. E.W. Leach read a description of two 

 species of shark found in the Scottish seas, illustrative of 

 a proposed subdivision of the genus Squalus of Linnaeus. 



At the meeting on the 1st of February, a communication 

 from Lieutenant-colonel Imrie was read, containing an ac- 

 cotmt of the district of country in Stirlingshire called the 

 Campsie Hills, illustrated by some curious geological fact? 

 observed by the Colonel on the coast of the Mediterranean. 

 The Campsie Hills consist of trap-rocks of great thickness, 

 under which sandstone occurs ; and below this lie beds of 

 limestone, with slate-clay, clay-ironstone, and some seams of 

 coal. The trap is in some places distinctly columnar, and 

 in many other places it shows a tendency to this form. He 

 observed, that these circumstances might cive occasion to 

 some geologists to class the trap of The Campsie district 

 with volcanic -products ; of which, however, he saw no 

 symptom. He then pointed out, that nature produces 

 these forms both in the moist and in the dry way, and 

 gave examples of both. In the moist way, he said that 

 these forms are seen in greatest perfection in warm climates, 

 and drew his example in this mode from the coast of Africa, 

 near the site of ancient Carthage; where a small lake, with 

 a deep clay bottom, had been drained by the accidental 

 breaking down of apart of its barrier, and where the clav 

 deposit had split into vertical cohunns eighteen feet high, 

 and from a foot and a half to three feet in diameter. The 

 example in the dry way he took from the island of Fela- 

 cuda, one of the most western of the Li pari islands. In 

 llie lavas of that island which have taken the columnar 

 form, he mentif)ncd having seen obsidian and pumice, 

 which had been in flow with the lava, and are seen com- 

 bined in what he termed one of iti. congealed streams. 



IMPERIAI, 



