604 ON GROOVES AND QDARTZITE BOULDERS AT DDKLNTIELD. 



inclined to think that the boulders came from some of the Pre-Car- 

 bonif'erous conglomerates in the north of England and Scotland. 

 These boulders may have been transported to their present position 

 by roots of trees. 



ilr. Blanfoed suggested that the grooves might have been caused 

 by floods at the time when the beds were being deposited. He 

 had seen similar excavations in plains over which water had passed. 

 He also noticed how rapidly evidence of glacial action in Car- 

 boniferous times is accumulating in various parts of the world. 



Prof. Bonnet pointed out that boulders were sometimes imbedded 

 in the coal, and did not always project above the seam. 



