THE GLACIAL PERIOD. 185 



till seem as if actually interstratified with the old strata. Per- 

 haps the most striking example of this peculiar phenomenon 

 which has been recorded is that shown in the quarry of Links- 

 field, near Elgin, which has been described by Captain Bricken- 

 den. 1 This quarry has been opened in limestone underneath 

 an overlying thickness of forty feet of Oolitic strata, which were 

 separated from the limestone by a sheet of boulder-clay two to 

 four feet thick. In order to raise the limestone it was found 

 necessary to remove the boulder-clay and strata resting upon it, 

 which, since the opening of the quarry up to the time when 

 Captain Brickenden examined the place (1851), had been done 

 to the extent of 120 yards in a direction at right angles to the 

 course pursued in the excavation of the limestone, the transverse 

 line or section of the quarry extending to 270 yards. Now, 

 over all this area the boulder- clay maintained its position 

 between the Oolitic strata above and the limestone below ; and 

 Captain Brickenden was "assured by an intelligent old man, 

 who had visited the quarry very constantly since it was first 

 opened, that at the distance of more than 100 yards from where 

 it now is the clay was observed to be about the same depth, 

 and overlaid, as now, by the same series of Oolitic strata in 

 their undisturbed position. On the north-western boundary of 

 the quarry the thickness of the intercalation increases consider- 

 ably, and there can be little doubt that in this direction the 

 clay obtained an entrance." The surface of the boulder-clay 

 and that of the strata between which it occurs is hardened, 

 abraded, polished, and marked with striae, indicating the direc- 

 tion in which the ice -movement took place, which is nearly 

 from north-west to south-east. Captain Brickenden was of 

 opinion that the boulder-clay had been intruded into its present 

 position. It is more probable, however, that the whole mass of 

 the Oolitic strata has been pushed out of place, and dragged 

 forward bodily over a pavement of boulder -clay under the 

 enormous mer de glace which pressed outwards by way of the 

 Moray Firth and overflowed all the low grounds of Elgin. 



1 Quart. Journ. Geol. Soc, vol. vii. p. 289. 



