150 GEOLOGY OF THE LOTHIANS. 



brous amethyst is also to be found at some points. Near an 

 isolated rock called Lot's Wife, a vein of felspar-porphyry 

 crosses the strata of greywacke, into which, at the planes 

 of contact, it is gradually found to pass. 



Having described the appearances at the Needle's Eye, 

 we shall next notice some other localities where the grey- 

 wacke is connected with granite. 



On proceeding along the bank of the Ladyland burn, a 

 streamlet which crosses the road about a mile and a half to 

 the south of Kirkbean, the greywacke is found in various 

 altered positions, dipping at high angles, and in some places 

 also much contorted. In several parts veins of felspar 

 porphyry cross the strata, but junctions are in no place visi- 

 ble. In mineralogical character these porphyry veins pre- 

 sent a perfect similarity ; they are composed of a compact 

 light reddish-brown felspar with imbedded crystals of fel- 

 spar, being identical, in every respect, with other porphy- 

 ries associated with the same strata in other parts of this 

 great transition district. As an examination of the bed 

 of this burn appeared to afford a chance of again ob- 

 serving a junction of the syenite with the greywacke, we 

 traced it through its whole extent, but unfortunately the de- 

 sired contact was not visible. In the Kirkbean burn, how- 

 ever, almost at its source there is a distinct exhibition of 

 the junctional relations between the granite and the grey- 

 wacke. In the other parts of the bed of this stream there 

 is nothing interesting exposed : there are a few porphyry 

 and felspar veins, but beyond their presence little else can 

 be made out ; they cross the strata and are frequently many 

 yards in breadth. As in the other points where the contact 

 of the granite and greywacke is exposed, the strata are here 

 found to abut against the unstratified rocks at high angles. 

 Some of the varieties are highly quartzose, and approach 

 almost to sandstone. Concerning the characters of the 



