438 T. V. Holmes—On Eskers or Kames. 
years since, I now think it extremely probable that the noted 
brecciated limestone, uncovered since 1858 by the retreat of the 
Upper Grindelwald Glacier, is a crush breccia. 
It may, however, be worth mentioning that another form of 
breccia is not uncommon to massive limestones, which we might 
call a “contraction breccia.” Excellent examples of this will be 
seen in the Carboniferous Limestone of the Meuse, and in the 
polished slabs now so commonly imported from that region into 
this country. Here, though “crush” or “strain” breccias also occur, 
I have no doubt that many have been produced by contraction of the 
mass in drying, with subsequent recementation by infiltration. Ifa 
mass of wet rock be elevated and thus by natural drainage deprived 
of its contained water, very considerable loss of volume may be the 
result, which under certain circumstances may lead to the mass 
cracking and even breaking up in situ. Subsequent depression and 
percolation of water with mineral matter in solution would cement 
these fragments into a solid rock. The formation of a ‘septaria 
stone’ is an analogous case. 
It is, however, needless to go on adding examples. Enough to 
say that ‘crush breccias,’ large and minute, are far from uncommon, 
especially among the most ancient crystalline rocks,. and very 
puzzling, especially from their simulation of true bedding, whether 
of coarse fragmental material or fine streaky bands, more or less 
schistose, so that the student will do well to bear in mind Professor 
Hughes’s cautions. It may, however, be added that in no case which i 
have examined is there the slightest trace, macroscopic or micro- 
scopic, of any melting of the rock. I have never been able to 
discover any fact in nature which gives the least support to the late 
Mr. Mallet’s ingenious, but (as I hold it) erroneous hypothesis on 
the cause of volcanic action. 
III].—On Hsxers orn Kames.? 
By T. V. Hotmzs, F.G.S. 
HE gravel mounds and ridges known as Eskers or Kames are, 
though conspicuous where they do occur from the variability of 
their outlines, very irregularly distributed in the districts in which 
they are found. Having been familiar with eskers in Cumberland, 
I was asked by Mr. H. B. Woodward to visit him at Fakenham 
this spring for the purpose of seeing whether certain ridges and 
mounds in the neighbourhood of Glandford and Blakeney were such 
as are called eskers in the north. And I found that Mr. Whitaker 
had also met with ridges of doubtful character a little west of Great 
Massingham. Having just had, accordingly, the advantage of visiting 
both the localities mentioned, in the company of Messrs. W. Whitaker, 
H. B. Woodward, and J. H. Blake, this seemed a good opportunity 
of introducing the subject of eskers to the Norwich Geological 
Society. The extreme irregularity of their distribution is well 
illustrated by the fact that not one of the gentlemen named had 
1 A paper read before the Norwich Geological Society, May Ist, 1883. 
