OF THE earth's SURFACE. 177 



low, or standing upon its eastern side. Of these, Ravelstone, 

 Craigleith, and Blackcraig, are the principal, well known as ex- 

 cellent quarries. From each of them a tail or prolongation 

 extends to the eastward, formed chiefly of the blue clay alrea- 

 dy mentioned, together with beds of sand and gravel. These 

 decline very gently, and maintain, to a considerable distance, 

 the individual character given to each by the firm mass produ- 

 cing it. These ridges, however, are occasionally interrupted 

 by the interference of the same principles ; as we see well illu- 

 strated near the rock of Craigleith Quarry, by which the tail 

 extending from the Maiden Craig, (another sandstone mass to 

 the westward of it,) is abruptly cut off. 



From Corstorphine Hill to the eastward, the country em- 

 bracing all the space between Edinburgh and the sea presents 

 one continued series of ridges, upon one of which the New 

 Town of Edinburgh stands. It is an important circumstance, 

 that these ridges maintain a very correct parallelism with each 

 other, with the tail of the Castle rock, and of the Calton Hill, 

 and with the alluvial prolongations that extend to the eastward 

 from all the eminences of this neighbourhood. And a series 

 of parallel ridges occur also on the south side of Edinburgh, 

 extending from all the rocky eminences, as may be well seen 

 on the road leading to Dalkeith, which passes over several of 

 these ; one of the most remarkable of which is, that on which 

 the village of Libberton stands. 



Such an arrangement cannot have been the work of the 

 diurnal waters produced by our common rains ; for the 

 course of such waters, flowing by the action of gravity, 

 and guided by the general slope of the country, which de- 

 clines towards the Frith of Forth, ought to have produced 

 depositions nearly at right angles to those under considera- 

 tion. It is in vain that a vast duration is ascribed to the influ- 



VoL. VII. Z ence 



