Mr. WiTBAM on the Red Sa7idstones of Berwickshire. 183 



I cannot help now observing how cautious we ought to be in pronounc- 

 ing, from mineralogical characters alone, the nature of any of these Sand- 

 stones. Nothing but exact observation upon position, and upon their 

 alternation, can justify our deciding upon the series to which they 

 properly belong. The similarity to each other, in hand specimens, 

 between many of the rocks of this formation and the proper new Red 

 Sandstone, is often so striking, that the most experienced observer, 

 without such precautions, must be liable to very gross mistakes. 



By this investigation, two features are exhibited in these subordinate 

 beds of the above-named formation, which before were supposed only 

 to exist in much more recent deposits. 



First, accompanying the usual fossils belonging to the class Vascular 

 Cryptogamia, viz. the Sigillarice, the Lepidodendrce, the Stigmarice, and 

 Equisetce, so common in these measures, you have in this Field, embedded 

 in Shale, great abundance of Gymnospermous Phanerogamous plants. 

 The two localities already observed are seven miles apart, and I can- 

 not entertain a doubt, that vipon the banks of the White and Black 

 Adder and many other localities, were workings to be carried through 

 these Shale beds for any purpose, great abundance of these singular 

 fossils would more than repay those interested in such novel discoveries. 



Secondly, the presence of Gypsum in the Sandstones and the Shales, 

 containing beautiful crystals of Selenite, has, in deposits so low down, 

 hitherto, I believe, escaped notice. 



My attempt, therefore, to ascertain the true position of the Red Rock 

 of Berwickshire leads me to think, that there cannot remain much doubt 

 that the Mountain Limestone series extends from the point where the 

 first Limestone appears on the coast of Northumberland, to the Transi- 

 tion range of the south of Scotland, and that beds of Coal have been 

 worked near Ross, lying immediately upon the Gi'eywacke, and are 

 now found a few miles south of Dunbar, in a similar position : how far 

 north this Mountain Limestone group may extend, will, possibly, at a 

 future period, be the subject of another paper. 



VOL. r. c c 



