age of Arthur's seat, edikburgh. 



139 



Fig. 1. — Section on south side of the Queen's Drive, Edinburgh. 



[Copied from that given in the memoir on the geology of the neighbourhood 

 of Edinburgh (1861), p. 23.] 





Fig. 2. — The same Section, corrected so as to conform with the map 

 -published in 1864 (sheet 2 of the 6-inch map of Edinburghshire). 



QUEENS DRIVE 



A. Coarse agglomerates &c. 



B. Basalt of the Lion's Haunch. 



C. Sandstones &c. 



D. Intrusive mass of dolerite. 



E. Sandstones &c. 



F. Doleritic lava stream. 



Gr. Eed nodular ash. 



H. Eed ashy sandstone with marly 



partings. 

 K. White cherty limestone, probably 



overlain by sandstone. 

 L. Green felspathic ash. 



[In examining this interesting section, and weighing the evidence 

 which it affords, it will be necessary to bear in mind that it is not 

 exposed in a vertical plane, but in one having a slope of about 45° 

 with the horizontal. We have therefore, even if fig. 1 be the true 

 interpretation of the rocks exposed, no proof of unconformable over- 

 lap of the agglomerates A upon the lower beds ; the agglomerates 

 may occupy a great vertical fissure in the latter. But if, on the 

 other hand, we accept fig. 2 as the true interpretation, the idea of 

 unconformable overlap must be rejected, and that of the agglomerates 

 lying in a great fissure be accepted.] 



