676 MR DAVID MILNE HOME ON THE BOULDER-CLAY OF EUROPE. 



flakes of the laminated blue clay were lying in it. This mass of intruded 

 (boulder) clay always presents great irregularities in a section. At one place it 

 is scarcely a foot thick, allowing the Wealden beds to rest nearly on the Corn- 

 stone. At a short distance it rises abruptly to the height of ten feet, in the form 

 of a cone, from the apex of which several narrow bands stretch up through the 

 fissures of the overlying mass, looking like veins of red granite among crystalline 

 rocks. At one place the boulder-clay formed a rounded mass, and the super- 

 incumbent bands of limestone were folded neatly over it, so as to present the 

 appearance of a stone arch. By the movement, a number of fissures had been 

 caused in the overlying bands, into which the clay had been forced up. Some of 

 these rents were 6 feet in length." 



"It may be noticed that the surface of the Cornstone, when cleared of the 

 till, is found finely smoothed and polished ; any hollows on the rock are also 

 smooth and polished. The Cornstone strata are not in the least disturbed." 



Mr Martins had the goodness to send with his letter two or three sections, 

 showing the relative positions of the boulder-clay to the rocks above and below 

 it. These sections, it is right to add, were made by Mr Martins from memory, as 

 the quarry had ceased to be used, and was filled with rubbish. The sections, 

 therefore, can be taken only as giving a pictorial representation of what is 

 described in Mr Martins' letter.* 



Both Captain Brickenden and Mr Martins express their conviction, produced 

 by a study of the sections when they were exposed, that the boulder-clay had 

 been forced in between the upper Wealden bands and the lower Cornstone rock. 

 Captain Brickenden notices particularly the iwlislied and striated surface of the 

 Cornstone, caused by the passage and attrition of the overlying boulder-clay. 

 He states that the direction of the striatums was N.W. and S.E., and he inferred 

 from the appearances, that the boulder-clay had been thrust in from the N.W. 

 When he visited the quarry, the exposed boulder-clay had "a bright red colour," 

 which made the embedded fragments of the purple Wealden rocks all the more 

 striking. The explanation suggested by Captain Brickenden is precisely the 

 theory which it is the object of the present Memoir to support, viz., that the 

 materials of the boulder-clay " had been subjected, to the action of vast and 

 extensive masses of ice, which by continuing to press onwards the accumulations 

 of clay retained beneath it, had, by a force superior to that which the beds above 

 could offer in resistance, eventually produced the phenomenon." 



If it be said that a glacier could have propelled and pushed the boulder-clay 

 between the rocks, quite as well as masses of floating ice, the question would be, 

 whether, in the places referred to, where the boulder-clay has apparently been 

 pushed forward en masse, there was any probability of a glacier having existed. 



* Two of these sections are given on Plate XXXI. 



