RAMBLES OF A GEOLOGIST. 327 



must be something distinct from the substance itself, just as 

 the dye of a handkerchief is a thing distinct from the silk or 

 cotton yarn of which the handkerchief has been woven. The 

 stagnant water above, acidulated by its various vegetable so- 

 lutions, seems to have been in some way connected with these 

 appearances. In every case in which a crack through the 

 clay gives access to the oozing moisture, we see the sides 

 bleached, for several feet downwards, to nearly the colour of 

 pipe-clay ; we find the surface, too, when it has been divested 

 of the vegetable soil, presenting for yards together the ap- 

 pearance of sheets of half-bleached linen : the red ground 

 of the clay has been acted upon by the percolating fluid, as 

 the red ground of a Bandona handkerchief is acted upon 

 through the openings in the perforated lead, by the discharg- 

 ing chloride of lime. The peculiar chemistry through which 

 these changes are effected might be found, carefully studied, 

 to throw much light on similar phenomena in the older for- 

 mations. There are quarries in the New Red Sandstone in 

 which almost every mass of stone presents a different shade 

 of colour from that of its neighbouring mass, and quarries 

 in the Old Red the strata of which we find streaked and 

 spotted like pieces of calico. And their variegated aspect 

 seems to have been communicated, in every instance, not dur- 

 ing deposition, nor after they had been hardened into stone, 

 but when, like the boulder-clay, they existed in an interme- 

 diate state. Be it remarked, too, that the red clay here, 

 evidently derived from the abrasion of the red rocks beneath, 

 is in dye and composition almost identical with the sub- 

 stance on which, as an unconsolidated sandstone, the bleach- 

 ing influences, whatever their character, had operated in the 

 Palaeozoic period, so many long ages before ; it is a repeti- 

 tion of the ancient experiment in the Old Red, that we now 

 see going on in the boulder-clay. It is further worthy of no- 

 tice, that the bleached lines of the clay exhibit, viewed hori- 



