94 GEOLOGY OF THE LOTHIANS. 



riously coloured slates dip under the trap to the E. S.E. at 

 20° and 25° ; but on crossing the ridge of trap, the strata 

 completely change their position, and dip under it to the 

 N. N.W. at 45°. The appearances which the strata assume 

 when near the trap are of the most satisfactory nature ; all 

 are indurated, the sandstone passing into granular quartz 

 and hornstone, while the slates assume those characters 

 which they usually exhibit, when acted upon by ignige- 

 nous rocks. The trap of Whitberry varies in different parts ; 

 it is however principally composed of a rock of very large 

 granular greenstone, arranged in beautifully regular tabu- 

 lar concretions, and associated with a ferruginous basaltic 

 greenstone, exhibiting also in many places the tabular 

 structure. When next the stratified rocks, the Plutonic 

 masses become more compact, losing their crystalline struc- 

 ture for a more or less earthy state of aggregation. Inter- 

 posed between the sandstone strata and the greenstone a 

 trap-tufa in some places occurs, consisting of a basis of red 

 wackaceous trap, in which are imbedded angular-shaped 

 masses of red sandstone, limestone, and slate, identical with 

 those which are in contact with the greenstone.* 



We have now described the various relations of the prin- 

 cipal mass of the unstratified rocks of East Lothian to its 

 attending strata, and shall now finish this part of the sub- 

 ject by noticing other, but less extensive, examples of igni- 

 genous formations. 



On leaving Whitberry Point, and proceeding in the di- 

 rection of Dunbar, a vast extent of flat sandy beach com- 

 pletely hides, as far as Belhaven, all the subjacent rocks ; 

 at the confluence, however, of the Belton water and the sea, 



* Dr Macknight, in the 2d volume of the Transactions of the Werne- 

 rian Natural History Society, has described this point under the name 

 of " TtaveiLsheugh." 



