188 ' ON THE REVOLUTIONS 



the zig-zag form of the rent being softened off into a waving 

 hollow of uniform breadth, highly characteristic of the violent 

 action of a stream vested with the power of grinding. It is 

 remarkable, too, in more than one of these grooves, that at 

 their Eastern extremity, after maintaining an equal wideness 

 throughout, they suddenly spread to right and left, and lose their 

 form. These grooves are three or four feet in length, by four 

 or five inches in breadth. When a rent has occurretl at right 

 angles to the current, the rock has been ground across it, with- 

 out visible modification of the action. 



No, 6. From Craighouse Quarry (following the road which 

 leads to Corstorphine along the western face of the hill, and 

 passes on the east side of Clermiston) we arrive at a ruined cot- 

 tage, on the left hand, at the mouth of a little ravine which here 

 crosses the main ridge, and is called the Glen of North 

 Clermiston. Close to the road, immediately upon the north side 

 of the ruined cottage, and within the wall which encloses the 

 wood, the whinstone almost bare, presents to view a continued 

 series of parallel grooves, one of which is twenty paces in length, 

 and others more. The hollows of these grooves are filled with 

 moss and earth, which, being removed, and the rock drenched 

 with water, a set of furrows shew themselves perfectly well 

 characterised, having the same bearings with those of the other 

 specimens, so as to lie quite at right angles with the longitudi- 

 nal direction of the hill. This situation must be at least one 

 hundred feet perpendicular above Craighousei 



No. 7. About two hundred yards farther to the south, below 

 the road, stands a group of cottages, comprehended under the 

 same name of North Clermiston. Opposite to these, and 

 above the road, is a barren space which has been the seat of 

 former quarries. Here several rocks are visibly dressed with 

 the large diluvian features ; and at one spot, just twenty-sis 



paces 



