86 DK THOMSON ON TUB STUATA OF BERWICKSHIRE. 



itself being superior to the carboniferous series. Now I traced a calca- 

 reous rock lying under the Berwickshire sandstone (which, it should be 

 observed, is characterized by containing beds of sulphate of lime) for 

 three miles, in a northerly direction from the Tweed at Birgham, and as 

 many to the westward from the same point. In addition to this, I 

 analyzed the rock, and found it to consist of one atom of carbonate of lime, 

 and one atom of carbonate of magnesia, a composition exactly similar 

 to that of the magnesian limestone which occurs on the coast near Sunder- 

 land. What could be the legitimate conclusion from these facts, then, 

 but that this rock constituted the magnesian limestone formation ; and 

 that whatever sandstones I should find in contact superior to it, would 

 belong to the new red sandstone formation ? If the magnesian limestone 

 had occurred only in the form of thin beds of insignificant extent, then 

 it might have been granted, without compromising the claim of that rock 

 to the title of a formation, that the rock with which they were connected 

 was a member of the carboniferous series, or even had its position be- 

 neath them : but this was not the case ; and therefore it is as clear as 

 the orb of day when at its meridian brightness, that if the Berwickshire 

 sandstone belongs to a series which is older than the carboniferous rocks, 

 the magnesian limestone is still older than the latter set of strata ; and, 

 further, that the sandstones overlying the magnesian limestone, and 

 which have been hitherto termed new red sandstones, are also older than 

 the coal rocks. Hence it will be impossible to make any distinction be- 

 tween old and new red sandstone. That the Merse rocks are intimately 

 connected with the carboniferous group, is obvious, from the circum- 

 stance of our meeting with considerable remains of plants in the quarry 

 at Whitsom, bearing a strong resemblance to Catamites. But is it not 

 agreeable to what we should expect to meet with, that rocks deposited 

 subsequently over others, should approach somewhat in their nature ? I 

 have already stated this in some botanical observations published in the 

 last number of the Transactions, and written in July or August last year. 

 I have in vain long endeavoured (and many a day have I fruitlessly pur- 

 sued this important object) to discover a section where the junction of 

 the red sandstone, and decidedly coal rocks, could be detected. But 

 until their relative positions are demonstrated, it would be unphilosophi- 

 cal to deny that the Berwickshire sandstone is new red sandstone. 



Having made these remarks, in order to excite attention to the eluci- 

 dation of the age of the Berwickshire strata, I proceed to state, that the 

 true coal strata only begin to exhibit themselves on the banks of the 

 Tweed. At Lennelhill, where fossil vegetables have been so uumerci- 

 fully quarried by amateurs, as to leave scarce a vestige for the man of 

 science, the only person to whom they could be of the slightest value, 

 the limestone and shale containing microscopic shells are clearly mem- 

 bers of the carboniferous group. They occupy a considerable portion 

 of the banks of the river in this neighbourhood ; but at no great distance 



