296 
TUB GEOLOGIST. 
covering ilic boulders just mentioned, is a bed of yellow sand, d d, 
that becomes rather ferruginous inferiorly ; this bed is thickest 
where it abuts against the gi'avel, aiid deci-eases in thickness as the sur- 
face slopes, until it thins out and disappears ; its maximum thiclcness 
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 brown 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 with mariiie parasites, and several are lodged in slight hollows. 
An d though I have Imown this locahty for many years, and have almost a personal 
acquaintance vsdth some of the boulders, I have never observed indications of 
any of them having shifted their position. Indeed, it is astonishing to obsei-ve 
how little, or rather how slowly the boulders are affected by the surf ; there are 
some whose distance from the cliff is indicative of the period that must have 
elapsed since they wore washed out of the clay, which stiU retain an angularity of 
Bui'face ; and there are others which have laid on tlie beach for years — where not 
scoured by sand or gravel — that have not yet lost their striated sm-faces. In the 
cliff or bank of clay other large boulders may be seen i-eady to drop out, and at 
the base of it, or in close vicinity, are others which have lately fallen, to whose 
number eveiy wiiitoi''s frosts and storms make adtUtions. 
