Reports and Proceedings. 283 
operations of the sea and rivers—the first producing planes of denu- 
dation, the latter removing material along their channels from the 
higher levels, with the concurring agencies of frost, ice, rain, and 
springs, were alluded to; and as great agencies of waste, they were 
applied in the consideration of the three kinds of scenery in Scot- 
land ;—that of the Highlands, that of the Southern Uplands, and 
that of the great Central Valley. Mr. Geikie explained that the 
Highlands have been at one time covered by a great sheet of Old 
Red Sandstone conglomerate, which has been worn into, and even 
penetrated by, furrows and hollows, often down to the massive 
schists beneath, which come out in enormous undulations and rugged 
outcrops, often forcibly but wrongly suggesting themselves as the 
original features of the country. The wonderfully uniform level of 
the mountain-tops refers to a great plain of marine denudation sub- 
sequent to the formation of the Lower Old Red Sandstone, coincident 
with a sinking of the land, and followed by upheaval and denudation 
by running water and by great glaciers or an ice-sheet, during 
incalculably long periods of time. In the Southern Uplands the 
Upper Old Red Sandstone had been horizontally planed by the sea 
during either a rising or sinking of the land, and subsequently fur- 
rowed by drainage-systems of running water and glaciation. In the 
Central Valley the hard rock-masses of igneous origin have resisted 
to a great extent the denuding agencies, and thus modified what 
would otherwise have been conditions very similar to those seen in 
the scenery of the other districts. 
2, At the monthly meeting of the Society, on November 10th, the 
Rev. H. W. Crosskey in the chair, Mr. Wunsch moved ‘That a stand- 
ing committee be appointed to collect information as to the relative 
level of the glacial shell-beds and the present sea-level; also, to 
concert measures for placing marks on various portions of the sea- 
shore and in river-beds, for the purpose of ascertaining whether any 
variations in the present relative level of sea and land are taking 
place, and also for the purpose of ascertaining at what rate sea- 
shores are eroded and river-beds worn down; and to take any other 
measures they may deem expedient for collecting data to serve as a 
basis for future inquiries into recent geology.’ This was agreed to. 
Messrs. John Young and James Thomson exhibited plates of three 
species of Chiton from the Carboniferous Limestone of Western 
Scotland. Mr. Young pointed out the characters of each species, 
and stated that two of them appear to be undescribed, and the other 
agrees very Closely in the form of the plate, and its granulated mark- 
ing, with Chiton gemmatus(De Koninck). He further stated that the 
remains of Chitons are very rare in British Carboniferous strata, 
having been detected in England only within the last few years, and 
that the three species then exhibited were the first that have been: 
recorded from Scotland, their localities being Craigen Glen, Campsie, 
Robroyston, near Glasgow, and the banks of the Avon near Strathaven. 
Mr. Thomson also exhibited specimens of Camarophoria globulina, 
Lingula Thomsoni, and several species of Hntomostraca from the 
Campbeltown Carboniferous Limestones, including examples of the 
genera Leperditia, Kirkbya, and Cythere. 
U2 
