272 R. Chambers, Esq., on Glacial Phenomena 



right angle to the line of the coast. All of these blocks have 

 flat sides uppermost, and all of these flat sides are striated in 

 one direction, — namely, in that of the line of blocks. There 

 are also some appearances of a hollow on the surfaces of these 

 curious pavements, as Mr Miller calls them, as if some enor- 

 mous wheel had run along the surface in that direction, and 

 left in it a slight track. What is of the highest importance, 

 the line of the blocks, and that of the striation, are from 

 about WSW., both at Seafleld and at Magdalen Bridge, 

 (examples three miles apart,) this being the direction of the 

 striation upon the fast rock throughout the whole of our dis- 

 trict, so that the presumption for a community of cause be- 

 comes very strong. There is, in short, a surface of the 

 boulder clay, deep down in the entire bed, which, to appear- 

 ance, has been in precisely the same circumstances as the 

 fast rock -surface below had previously been. It has had in 

 its turn to sustain the weight and abrading force of the glacial 

 agent, in whatever form it was applied ; and the additional 

 deposit of the boulder clay left over this surface, may be pre- 

 sumed to have been formed by the agent on that occasion. 



Professor Fleming, to whose superior experience I am 

 much beholden in this part of my subject, assures me that 

 the deposit most generally found in our district over the 

 boulder clay is a fine laminated clay, or silt, evidently derived 

 from the preceding formation, in which it sometimes fills up 

 considerable irregularities. This is the clay generally wrought 

 for bricks and tiles throughout Scotland, so that we may be 

 said to be indebted remotely to these glacial phenomena, both 

 for the houses which shelter us, and the increase of food re- 

 quired by the exigencies of a large population. 



The laminated clay is succeeded by, or perhaps we ought 

 rather to say, associated with, an abundant formation of fine 

 sand, disposed in beds, and intercalated with gravel. Very 

 often there are interlacings of the sand and the clay, or curi- 

 ous nests of sand within the clay, shewing rapid and abrupt 

 alternations of conditions in the sea, in which the whole had 

 been formed. In this compound formation, as I venture to call 

 it (No. 2), shells are found — My a truncata, Saccicava sul- 

 cata, Tellina calcarea, Astarteborealis, Cyprina islandica, 



