296 



THE GEOLOGIST. 



covering tlie boulders just mentioned, is a bed of yellow sand, d d, 

 that becomes rather fermginous inferiorly ; this bed is thickest 

 where it abuts against the gTavel, and decreases in thickness as the sur- 

 face slopes, until it thins out and disappears ; its maximum thickness 

 is about six feet, its breadth about fifty yards ; where it is thickest, 

 thin seams of brown clay, and more rarely of carbonaceous matter 

 like coal-drift, are interspersed through its mass ; and occasionally 

 towards its lower portion are small lenticular beds of gravel. Above 



15 feet. 



Lign. 2.— a, Clay; b, Sand; c, Limestone, 



the sand is a bed of browTi clay, e e, which increases in thickness as 

 the surface slopes, being thinest where the sand is thickest, the upper 

 portion^ graduating into the soil. The united thickness of these beds 

 of alluvium is not more than nine feet where thickest, usually much less. 



tially covered vdth. marine parasites, and several are lodged in slight IioIIotts. 

 And though I have known this locahty for many years, andliave almost a personal 

 acquaintance i^-ith some of the boulders, I have never observed indications of 

 auy of them ha^ang shifted their position. Indeed, it is astonishmg to observe 

 how little, or rather how slowly the boulders are affected by the surf; there are 

 some Avhosc distance fi'om the cliff is indicative of the period that must have 

 eln]iscd since they were washed out of the clay, which stiU retain an angularity of 

 surthco ; and there are others which have laid" on the beach for years— where not 

 scoured by sand or gravel— that have not yet lost then- striated sm-faces. In the 

 chff or bank of clay other large boulders may be seen ready to di'op out, and at 

 the base of it, or m close vicinity, are others which have lately faUen, to whose 

 number every winter's frosts and storms make additions. 



