102 GEOLOGY OF THE LOTHIANS. 



also in one or two places, but uever of a size sufficient to be 

 of importance in an economical point of view. Concerning 

 the relations of this crystalline rock to the grey wacke series, 

 it is to be regretted, that the entire absence of sections at 

 those points where the two rocks come into j unction, prevents 

 any change, either in mineralogical structure or position, 

 from being observed ; in one place only, the greywacke is 

 found in the neighbourhood of the syenitic greenstone rock, 

 and then, there is no greater appearance of alteration than 

 is exhibited in other parts where no plutonic rocks are visi- 

 ble. It must, however, be stated that the strata abut against 

 the ignigenous mass at about 75°, but in no instance is the 

 syenitic rock found to alternate with the greywacke. The 

 same covered state of this country, which renders the exact 

 relations of these two rocks to each other impossible to be 

 seen, causes also the topographical boundaries of both to be 

 obscure. After minute examination, however, the crystalline 

 rock of Fassney may be stated to be bounded by a line run- 

 ning along the lower part of the acclivity of Priestlaw Hill 

 to Fainshiel ; it then runs along the foot of Dod Hill, to 

 nearly opposite the old castle of Gamelshiel, when it bends 

 with a circular direction to Mill-know ; stretches along the 

 foot of Spartleton Hill, and joins the southern line of its 

 boundary at about half a mile to the west of Snailscleugh ; 

 and thus appears to form the lowest rock or basis of the 

 Hills of Priestlaw, Spartleton, and Painshiel.* After the 

 greenstone rock has disappeared in this stream, near the farm 



* In Berwickshire a syenitic greenstone, similar to that of Fassney 

 Water, forms the hill of Cockburn Law, and like it, is connected with 

 the greywacke strata. The modes of its association here, however, are 

 better exposed than in the Fassney, and in several places it may be found 

 traversing the transition strata. The Syenitic Greenstone of Fassney 



