488 Mr. J. Bryce on Striated and Polished, Rocks 



toughness and hardness, that the quarry was abandoned; and 

 to this circumstance we owe the preservation of perhaps the 

 most perfect specimen of striated rocks to be seen in the three 

 kingdoms. I have visited most of the localities in Scotland 

 where such rocks occur, but have met with nothing so perfect. 

 It is impossible by any drawing or description to convey an 

 adequate notion of the strikingly beautiful and perfect cha- 

 racter of the striation, polishing, and rounding of the rocks 

 here exhibited, The accompanying Plate (PI. II.) representing 

 a portion of the surface will assist. It is from a drawing most 

 kindly taken at my request by James Henry Gough, Esq. of 

 Kendal, and transmitted for the illustration of my paper laid 

 before the Edinburgh meeting already referred to. 



The surface is traversed by four eminences of an elliptic 

 form, running in the direction of the breadth, smooth, rounded 

 and highly polished, and presenting exactly the character of 

 the most perfect specimens of the " roches moutonnees," so 

 well-described and figured by Agassiz in his work on the 

 Alpine glaciers. These eminences, and the hollows between, 

 are thickly covered in every part by striae and grooves, the 

 great majority of which run in the direction of 10° W. of 

 magnetic north, or 34° W. of true north, taking the variation 

 at 24° W., which I am informed by Prof. Phillips of York, is 

 its present amount in this district. They thus -point very nearly 

 in the direction of the opening of Kentmere, or more exactly 

 in the direction of Staveley Head, a hill of no great elevation 

 (1000 feet?) on the western side of the entrance to Kentmere. 



Most of the striae are very fine, being mere touches as by 

 a delicate graving-tool; others are traced with greater bold- 

 ness ; and the grooves are often of considerable width, as 

 from \ inch to 1^ inch, or perhaps more in a few cases. A 

 great many of the striae are inclined to the prevailing direction 

 already given ; but the angles seldom exceed a few degrees, 

 and by far the greater number deviate very little from the 

 direction above stated. This direction is across the beds, or 

 at right angles to the stratification of the slate, which here 

 belongs to the division called the Lower Ludlow Rock by 

 Prof. Sedgwick. It is plain, indeed, that the striae have no 

 connexion with, or dependence on, the internal structure, or 

 the unequal wearing of component laminae having different 

 powers of resisting the causes of waste. From the very com- 

 pact character of the Lower Ludlow Rock, in many places 

 it is often difficult to determine the position of the true beds. 

 " This can sometimes be done," says Professor Sedgwick, 

 " by help of alternating bands of coarser materials wherein the 

 original bedding has not been obliterated by the slaty struc- 



