248 Professor J. W. Gregory — The Solway Basin — 



5. Another improbability involved by the acceptance of the Upper 

 Gypseous Shales is the conclusion that in addition to a minor uncon- 

 formity between the Stanwix Shales and the Kirklinton Sandstone 

 (Holmes, 1889, p. 242) there is a very marked unconformity at the 

 base of the Lias. Mr. Holmes' section (1899, p. 41) shows the Lias 

 transgressing from the Gypseous Shales over the Kirklinton Sandstone 

 on to the Stanwix Shales. This unconformity is based mainly on 

 a boring made at Great Orton in 1781. According to the record 

 quoted by Mr. Holmes (1899, p. 22) this bore " found a blue stone 

 3 fathoms from the surface — continued with different stone, mostly 

 bluish till 38 fathoms, then changed to red stone or clay sometimes 

 mixed with veins of white till they came to 60 fathoms ". Mr. Holmes 

 interprets this record as showing that the Lias extended from 3 to 38 

 fathoms, and that the bore then entered the Upper Gypseous Shales 

 and kept in them to the bottom of the bore at 60 fathoms. H. B. 

 Woodward, on the other hand, in a passage in his memoir on the Lias 

 quoted by Mr. Holmes (1899, p. 38), considered that the upper 

 210 feet of "different stone, mostly bluish " included some Rhsetic 

 beds, and this conclusion would appear to be most probable. The 

 recorded "veins of white", instead of being veins of gypsum, the 

 probable explanation, might possibly be based on thin beds of 

 white or grey sandstone ; and if so the lower beds might be either 

 Stanwix Shales or Kirklinton Sandstone. But Mr. Holmes' conclusion 

 that the beds containing these white veins are of gypsum is prob- 

 ably correct, as Gypseous Shales may be expected beneath a thin 

 layer of Upper Keuper near Great Orton. The unconformity repre- 

 sented by Mr. Holmes in the Carlisle Memoir at the base of the Lias 

 is possible ; but the persistent conformity of the Lower Lias, Bhsetic, 

 and. Upper Keuper is so widespread throughout Britain, that it 

 requires stronger evidence than the meagre description of the Great 

 Orton bore to establish a strong unconformity between the Lower Lias 

 and the Keuper. 



6. The abandonment of the assumed upper series of Gypseous 

 Shales would remove the main difficulty in the interpretation of the 

 Carlisle district, viz. the assumption that west of Carlisle there is 

 above the St. Bees Sandstone a bed of Gypseous Shale which is several 

 hundreds of feet in thickness, and of which there is not a trace along 

 the outcrop of the St. Bees Sandstone, east of Carlisle ; although to 

 the south-east of the city there is a thick bed of similar Gypseous 

 Shale, below the St. Bees Sandstone. 



7. The Redkirk bore shows that the Permian beds at Bowness 

 should be nearer the surface than was expected when the Annan 

 Sandstones were regarded as the northern part of a sheet of St. Bees 

 Sandstone which extended in a simple synclinal under the whole 

 Solway-Carlisle basin. 



The Redkirk bore further shows that the St. Bees Sandstone north 

 of the Solway rests unconformably on the Carboniferous ; and south 

 of the Solway, to the west of Carlisle, the most northern certain 

 extension of the St. Bees Sandstone is in the band which passes 

 3 miles south of Carlisle, and continues through Dalston and "Wigton 

 to the coast at Allonby Bay. This band probably lies in a trough fault. 



