58 EEPORT OF THE MEETINGS FOR 1896 



Appendix II. 



Notes on the Geology of the Upper Vale of Whitadder. 1847- 1850. 

 By the late William Stevenson, Duns. Extracted from 

 MSS. in the possession of the President. 



A lake or loch of considerable extent appears to have at one 

 time existed between Elmford and Longformaeus, occupying 

 the valley between these places, and probably extending up the 

 Whitadder as far as St. Agnes. Between Whitchestcr and 

 Caldra a beautifully defined alluvial plateau or terrace forms a 

 very striking object. It occurs at an elevation of about 25 feet 

 above the level of the haugh, or nearly 40 feet above the bed of 

 the Dye. The Conglomerate rises very little above the level of 

 the stream for a considerable distance, and the sections displayed 

 are generally of alluvium. The opposite side of the valley 

 presents similar alluvial phenomena. The terrace is not quite 

 level latitudinally, but dips a little towards the valley. Longi- 

 tudinally it appears to be quite horizontal. This will, however, 

 require to be determined by accurate levelling, which will also 

 tend to throw much light on the relation of this ancient body of 

 water to other lakes and water-courses, which have also formerly 

 existed in this portion of the Lammermuirs. The inclination of 

 the terrace would appear to indicate tidal action, and con- 

 sequently that the waters of the sea stood at that level, when they 

 moulded the alluvial matter of which it consists into its present 

 form. Accurate levelling may perhaps also decide this point. 



Near the bend of the VVhitchester burn, at about half-a-mile 

 from Elmford the Grreywacke is seen. It is hard, and dips 

 W.N.W. under a dyke of Porphyry of a whitish mottled 

 appearance, exactly resembling the boulders found in the Old 

 Eed Sandstone Conglomerate at Hardens, etc. Some soft 

 greenish Greyv\'acke Slate appears almost in contact with the 

 Porphyry, but this softness is perhaps due to weathering. 

 The hill on the east side of the road is also composed of 

 Porphyry. Near the mouth of Bothal Water (immediately 

 behind St. Agnes) the Greywacke is of a yellowish colour, and 

 presents some curious appearances, probably the result of 

 some modification of chemical action produced by igneout 

 agency, a kind of Claystone I'orphyry appearing in the vicinity. 

 The strata are nearly vertical, with a N.N.W. strike. The hill 



