14 Proceedings of the 



agent. It snows how, through those physical changes which have been 

 taking place in every geological era, and which, by altering the geogra- 

 phy, have also altered the climate, of wide regions, whole races may have 

 been extinguished.* 



II. On the Silurian and Old Red Floras of Scotland. By Hugh 

 Miller, Esq. — Mr Miller illustrated his paper by the exhibition of a 

 most interesting collection of the fossil remains of these little-known 

 plants. 



III. On the Homology of the Vertebrate Skeleton, and its representa- 

 tive Eso-STceleton of the Invertebrate Classes, with the application to 

 Zoology, Palaeontology , and Geology. By Professor M'Donald. — The 

 Professor exhibited a numerous collection of osteological preparations and 

 diagrams in illustration of his peculiar views. 



Wednesday, 28th March 1853. — Professor Fleming-, President, in the 



Chair. 



The following Donation to the Library was presented from the Author : 

 — "A List of the Mollusca hitherto found in the Province of Moray." 

 By the Rev. George Gordon, Birnie. 



I. Of Some Circular Mounds, covered with a Metallic Slag, which occur 

 on the Sloping Sides of the Gneiss Hills, Parish of Birnie, Moray- 

 shire. By William Rhind, Esq. (A specimen of the slag was exhi- 

 bited.) 



Several deposits of this metallic matter occur in circular, somewhat ele- 

 vated, mounds, about four feet in diameter, lying upon the moss-soil of the 

 moors, both in this locality and in some of the moorland slopes of the 

 country to the westward, the vague traditions of the county being that 

 they are the remains of iron-works, used by the armies that had in former 

 times passed over the country. A discussion ensued, in which Professor 

 Fleming, Mr Alexander Rose, and others, took part, on the probable cause 

 of the formation of this metallic matter, — whether it was accumulated by 

 fires occurring in the moors, or by solution, and subsequent deposition 



* On the night of the 16th ultimo, the thermometer of the Botanic Garden, 

 Edinburgh, stood as low as 1° above zero. Mr Miller was informed, however, by Mr 

 George Berry, Rosefield Cottage, who, in the behalf of science, carefully notes the ex- 

 tremes of temperature in the Portobello district, that the greatest cold indicated du- 

 ring the late frost, at nearly the level of the sea, in the locality in which so many 

 molluscs were killed, was 9f° above zero during the night of the 15th-16th, and 9J° 

 during the night of the 16th-17th. On the coast of Labrador, in the same latitude, 

 the sea freezes every winter for many miles from the shore, and the ice, even in mid- 

 summer, never melts in the ground beneath a certain depth, but forms a rock-like 

 subsoil. It is thus evident that the shells killed by the recent frost at Portobello 

 could not live in the same parallel on the American coast. 



