212 



THE GEOLOGIST. 



gether to be assigned, I believe, to atmospheric agency, either in this 

 or any of the numerous instances of crushed strata on moors. Most 

 of our stream-valleys, doubtless, owe their present features to the 

 softening of the climate and the final melting down of ice ; a tran- 

 sition not wholly insignificant in its effects even here, when we regard 

 those escarpments of deposits, whether marine or glacier-formed, 

 which tower loftily along many of their lines, sometimes on one side, 

 sometimes on the other, and individually faced, perhaps, by a gentle 

 verdant slope, that, with the gurgling brook below, seems to bide, as 

 it were, under a calm disguise, all the tumult of the past. One of 

 these escarpments on the line of the Pennington Beck is crested by 

 " hummocks " of boulder clay, so artificial in form that tradition 

 holds them as the site of an ancient castle, a half-encircling hollow, 

 apparently water-formed, answering for the remains of the castle- 

 ditch. I have an impression that geologists familiar with the phe- 

 nomena of the period, would experience little difficulty in assigning 

 this (together with much of the physical aspect of that truly inter- 

 esting vicinity) entirely to glaciation and its subsequent modifying 

 agencies. Almost every stone and pebble about the place is wonder- 

 fully grooved and striated. 



The other features of our stream-valleys are the stripes or terraces 

 which at various elevations and distances mark the former river-pos- 

 sessions, inasmuch as when tried by the spirit-level, they are found 

 to be on an extremely gentle incline, thus affording additional evi- 

 dence that all our brooks have been rivers, and our rivers mighty 

 streams. Deposits of river-gravels occur at some heights above the 

 present brooks, as in the vale of Newland before alluded to. There 

 deposits of dark gravels and sands lie in underneath the hillside 

 boulder clay, while the latter appears to have been scooped out by the 

 flow and wash of the down-passing current, into a true overhanging 

 river-bank, 50 feet above the bed of the present stream. 



Boulder clay. — In slightly sketching out the position of the boulder 

 clay in Furness, what knowledge I have of the nature and composi- 

 tion of that deposit is mainly derived from the teaching of the admi- 

 rable memoir before referred to, ' On the Phenomena of the Glacial 

 Drift of Scotland,' aided by the close examination of numberless 

 specimens obtained from many localities. Its stones and boulders 

 rounded, angular , flattened, smoothed, striated, seldom of remote trans- 

 portation, disposed ivithout stratification in a more or less clayey ma- 

 terial, are the characters by which it may be distinguished here. But 

 there are other peculiarities of the boulder clay in Furness for which 

 the above work somewhat prepares the student. These are the bars, 

 thin seams, or beds of gravels and sands, which very frequently are 

 found running through it. These are neither fluviatile nor marine ; 

 they precisely resemble in lithological character the true boulder clay 

 in which they occur : the stones, in some instances at least, have 

 scarcely lost their striation, and clearly owe their stratified disposal 

 to the percolation of water. In fact, such beds must have been 



