158 GEOLOGY OF THE LOTHIANS. 



GEOLOGICAL MAP OF THE LOTHIANS. 



In this map the several formations are laid down with an 

 accuracy as perfect as the nature of the ground allowed us 

 to do ; the dotted lines which separate the formations being 

 intended to express their limits in a general way. 



In regard to the Red Sandstone deposits, we wish to state 

 that several others occur in the Lothians, in addition to 

 those which we have marked on the map ; these, however, 

 from being on a small scale, and existing only as deposits 

 subordinate to the white sandstone series, we considered 

 it unnecessary to exhibit ; in many instances, also, their 

 extent of distribution, when compared with the scale of 

 the map, rendered this impossible. Several trap-dykes 

 have, for the same reason, been excluded ; a few, however, 

 have been represented, though on a larger scale than that 

 of the map. 



The limestone which occurs in the Lothians we have 

 only laid down on those parts where it is quarried or other- 

 wise exposed at the surface. Without much chance of mistake, 

 however, we might have connected many of these. When the 

 covered state of the country, however, prevented us from 

 being able to connect the limestones exposed by natural or 

 artificial means, we have coloured the intervening portions, 

 as the white sandstone series, from a knowledge that if lime- 

 stone did not form the uppermost rock continuously, it was 

 in almost every instance covered only by that group of 

 strata. 



By straight lines we have indicated the direction of the 

 strata, and, by an arrow placed at right angles to these 

 lines, the point of the compass to which they dip. In se- 

 veral instances we might, perhaps have drawn lines shew- 

 ing the outgoing of a stratum over a very considerable 



