361 
of Edinburgh^ Session 1864 - 65 . 
Much attention has been paid to the drift and superficial deposits. 
The subjoined table shows the subdivisions which are at present 
followed in mapping these formations on the ground : — 
Alluvium. 
Blown Sand. 
Peat. 
Eaised Beach deposits. 
Old Kiver-terraces. 
‘‘ Surface- wash,” — a deposit of sand, clay, gravel, or shingle, 
frequently containing scratched stones, and found on the 
high grounds of the southern uplands. 
Moraine rubbish of valley glaciers. 
Erratic blocks. 
Ee-formed Drift. Sands and gravels of the Kame or Esher 
series. Brick-clays, with Arctic shells. 
Upper Boulder-clay. 
Lower Boulder-clay. 
Bodies moutonnees (strisB effaced), are marked 
Do. do. striated, but not showing dis- 
tinctly from which quarter the 
ice moved . . . . 
Do. do. showing direction of ice-flow . 
Flat surface of striated rock, such as is often seen 
under the Boulder-clay . . . . . 
CD 
Do. showing the direction of ice-flow . . . 
The subdivision of the Boulder-clay into two zones was decided 
upon in the autumn of 1863, and since then the division has been 
carried out wherever practicable. The upper Boulder-clay is a 
looser, more gravelly deposit than the lower, and seems to have 
suffered a greater denudation. It has usually a more or less obscure 
stratification, contains a considerable admixture of travelled stones, 
with occasional fragmentary shells, and is regarded as having been 
formed in the sea, a short way off the land, by bergs from a dis- 
of the Upper Old Ked Sandstone. The hills to the south-west of the town of 
Ayr are formed of felstones and ashy conglomerates, which appear to belong 
to some part of the Old Red Sandstone period. They are at present under 
investigation by the Geological Survey. 
3 B 
VOL. V. 
