Royal Society of Edinburgh. 149 
tude.* It was shown how strongly this evidence goes to prove the 
former existence of a Boreal or Arctic climate in Scotland. 
The shells seem also to indicate some considerable rise in the 
level of the land. They are deep-water species—some of them very 
markedly so. Four distinct series of facts appear to show that 
they have not been washed up and transported, but are lying in the 
clay-bed where they originally lived. As the deposit is now rather 
above high-water mark, the fair inference would seem to be that 
the whole sea-bed of the Firth must have been considerably raised. 
Reference was made to the discovery of the glacial beds of the 
Clyde by Mr Smith of Jordanhill. They had been looked for on the 
Forth, but without success. Dr Fleming struck the first trace of 
them at Tyrie, but it was faint, there being only two or three 
specimens of the shells, and these he was led to think not indigen- 
ous. In the Hlie clay the same two species occur rather abundantly, 
along with others, all evidently in the clay-bed where they had 
lived. The group is so characteristic that there need be no ques- 
tion now as to the occurrence of the true old glacial beds with 
Arctic shells in the basin of the Forth. 
Various reasons were stated for holding that this bed is very 
closely connected with the boulder clay, being not improbably a sea- 
formation contemporaneous with some portion of that deposit. 
It was shown, that the facts brought to light in this section give 
us some glimpse into the circumstances under which the period of 
Arctic cold passed away. 
4, On the Remarkable Occurrence of Graphite in Siberia. 
By Thomas C. Archer, Esq. 
Monday, 16th March 1863.—Dr CHRISTISON, V.P., 
= in the Chair. 
The following Communications were read :— 
1. On the Polarization of the Atmosphere. By Sir David 
Brewster, K.H., F.R.S. 
2. Concluding Note on the Star Observations at Elchies. 
: By Professor C. Piazzi Smyth. 
3. On a new fossil Ophiwridan, from Post-pliocene strata of 
the valley of the Forth. By Professor Allman. 
I am indebted to one of our University students, Mr Peter 
Lawson, for a specimen of a star-fish, which he informed me had 
been found, along with many others, in a deposit of brick-clay near 
* The other species are—Savicava rugosa, large form, Tellina proxima, 
Astarte compressa, Leda truncata, L. pygmeea, Natica groenlandica, large form. 
Fragments also occur which seem to belong to Cyprina Islandica and Mya 
truncata. 
