Ill 



varying from one to two miles in breadth lying directly north 

 of th-e Carboniferous-Permian boundary-line, between Maryport 

 and the Caldew.* But north of Maryport, a walk along the 

 southern shore of the Solway shows nothing but drift or alluvium 

 from AUonby to Rockliffe. And north of a straight line drawn 

 from Allonby to Dalston, and west of the rivers Caldew and Eden, 

 the only inland sections — excluding those showing superficial beds 

 alone — are in the Lias country of Aikton and Orton. North of 

 the Allonby and Dalston line it is probable that the Gypseous 

 Shales soon begin to come on above the St. Bees Sandstone, or 

 they would be unlikely to attain a thickness of more than seven 

 hundred feet at Kelsick Moss. Whether they reach anything like 

 their maximum thickness at Kelsick Moss must remain uncertain. 

 On looking at a map, it appears that while the Kelsick Moss boring 

 is about nine-and -three-quarter miles south of the nearest northward 

 exposure of St. Bees Sandstone — -on the Annan Water below 

 Annan — it is only three miles north of the nearest section in that 

 rock to the south — in the cutting west of Leegate Railway Station. 

 And considering also that the Gypseous Shales attain a thickness 

 of three hundred and sixty-seven feet at Bowness, though St. Bees 

 Sandstone appears at Tordoff Point and below Annan on the 

 Scottish shore, I should be inclined to suppose them at their 

 maximum in the neighbourhood of Newton Arlosh rather than 

 that of Kelsick Moss. But of course it is not improbable 

 that no great difference may exist between the thickness 

 of the Gypseous Shales at Kelsick, Newton .\rlosh, Whitrigg, 

 Silloth, Pelutho, and other places that might be named. The 

 basin-shaped structure of the district is, I may remind you, shown 

 in the way in which water, evidently derived from the St. Bees 

 Sandstone, and flavoured by its passage through the Gypseous 

 Shales, rises to the surface in the Kelsick borehole. 



It is probable that any deep borehole on the coast between Bow- 

 ness and Allonby would pass through a considerable thickness of 

 Gypseous Shales before reaching the St. Bees Sandstone, the 



* A map showing this boundary line illustrates my paper on the Distinctive 

 Colours of the Carboniferous and Permian rocks. — Transactions, Pan vii. p. 79. 



