Mr Hugh Miller on Boulder- Glaciation. 157 



II. Fluxion-Structitres in Till. 



Longitudinal Striation of Stones. 



Their Striation by means of the Matrix. 



Glaciation of the Matrix. — Microscopic Boulders. 



Fluxion in Running Till. 



Fluxion- Structure in Till in situ. 



The Movement differential — Thickness of Fluxion layer. 



Distribution of Fluxion-Structures in the Till. 



Orientation by means of Fluxion-Structures. 



III. Conclusion. 



Introduction. 



The boulder-clay has long been considered a formation 

 sui generis. Its indiscriminate assemblage of materials of all 

 sorts and sizes and weights is the fact that seems first to 

 have struck the earlier observers of this singular deposit. It 

 was totally unlike any stratified deposit of which they had 

 experience. It had undergone no sifting or assortment, 

 either in the powdered matter that constituted its matrix, 

 or in the miscellaneous boulders that were flung as if at 

 random all through. Poor Eobert Dick, working all alone 

 up at Thurso, seems almost to have got angry with its 

 peculiarities. It differs entirely, says he, " from every other 

 thing on the earth's surface. It is not a conglomerate. It 

 would never, though consolidated, form a bed similar to 

 conglomerate. It is not a production of the Mosaic deluge. 

 It is not, strictly speaking, a production of the sea. It is 

 not the sweepings of a sea shore. No ! nothing of the kind. 

 No Mosaic deluge could have produced these beds of dark 

 stony clay. No ocean waves alone, by the friction of ten 

 thousand years on rocky strata, could have done it. No! 

 Tens and hundreds of millions of steam-mills, grinding stones 

 night and day for a thousand years, could not have done it. 

 No sea casts up anything like it. It is a distinct, generic 

 production, fairly entitled to a place by itself." 



The Boulder-Clay not Structureless. 



The apparently random character of the formation, how- 

 ever, has too often led geologists to consider it as structure- 

 less. " The boulder-clay," says Professor Hull, " is entirely 



