of Cumberland near the Solway. 417 



the St. Bees Sandstone immediately above Carboniferous rocks of 

 various ages has given rise to no differences of opinion among 

 geological surveyors. Nor have any of them felt that there was any 

 need of a special explanation of the structure of the district involving 

 the existence of hitherto unsuspected faults, etc. And in cases of 

 this kind the Geological Survey, in its knowledge of local develop- 

 ments, irregularities, and local peculiarities of Permo-Triassic rocks, 

 has necessarily a great advantage over any individual geologist. 



Professor Gregory thinks that the absence of older Permo-Triassic 

 rocks between the St. Bees Sandstone and Lower Carboniferous 

 rocks in this district demands the arrangement of a series of faults, 

 etc., to account for it. And that the presence of a thick bed of 

 Gypseous Shales above the St. Bees Sandstone (as demonstrated by the 

 Abbey Town boring) when there is one in the Eden Yalley district 

 below the St. Bees Sandstone, is so. nearly incredible as to make it 

 almost certain that the supposed St. Bees Sandstone in the boring 

 was really the Penrith Sandstone. But I have already mentioned 

 that R. Russell and I examined the cores of the lowest beds of the 

 boring and found them to be St. Bees Sandstone. In fact, the 

 surprise to us was simply to learn the great thickness of the Gypseous 

 Shales above it. And recognizing the St. Bees Sandstone as the 

 oldest bed of the Carlisle Basin, the absence of St. Bees Sandstone 

 beneath the Gypseous Shales, and the presence there of Penrith 

 Sandstone, would have seemed to us almost impossible ; and certainly 

 a state of things only to be explained by some arrangement of 

 faults, etc., of which there was no visible evidence. 



In short, the existence of the St. Bees Sandstone as the lowest bed 

 around the Carlisle Basin, and as resting mainly on Carboniferous 

 rocks, is unquestionable, and the absence of older Permo-Triassic beds 

 there between it and Carboniferous formations is simply a local state 

 of things to be recognized, not one to attempt to explain away as 

 though it were necessarily an illusion. 



Similarly, as regards the presence of Gypseous Shales both above 

 and below the St. Bees Sandstone. There is no inherent probability 

 in favour of either one or two. All the geologist has to do is to 

 ascertain which way the evidence points, and to decide accordingly. 

 In a district with Permo-Triassic areas like those near the Solway 

 much more local irregularity must be expected than in the Yale of 

 York or in Cheshire. Hence, at the Geological Society's discussion 

 last year on the geology of the Solway district, after Professor 

 Gregory's paper had been read, Dr. A. Strahan, the author of many 

 Geological Survey memoirs, including one on the neighbourhood of 

 Chester, showed no feeling of the impossibility of believing that the 

 St. Bees Sandstone could lie upon Carboniferous beds, but stated that 

 it " rested upon Carboniferous rocks along its margin both on the 

 Scottish and on the English sides of the Border ". 



Then, as regards the presence here and there of Carboniferous 

 inliers in the St. Bees Sandstone, they have long been known to 

 exist at Hethersgill, in Shalk Beck, and in the Roebeck. Hence the 

 presence of that at Red Kirk, mentioned by Professor Gregory, points 

 to no new conclusion, though interesting as a detail. 



DECADE VI. — VOL. II. — NO. IX. 27 



