1826.5 which appear on the Yorkshire Coast. 355 



impure calcareous concretions which abound with organic 

 remains.* 



The shale in this part of the coal formation not only alternates 

 with the beds of sandstone, but is mixed with them in every pos- 

 sible proportion, and often passes into them, and entirely replaces 

 them. This singular irregularity may be seen in almost every 

 section along the coast, especially in the cliffs south of Whitby. 

 In such circumstances the shale must necessarily be variable in 

 its composition. It sometimes contains balls and nodules of 

 clay ironstone ; in some places it becomes bituminous, and con- 

 tains thin beds of pure coal. The only beds, however, of suffi- 

 cient thickness and purity to be used, occur near the top and 

 bottom of the series. The higher beds were formerly wrought 

 on the north side of Cloughton Wyke ; and beds in the same 

 geological position (i. e. a few yards below the limestone of 

 Cloughton Wyke) have been wrought in several places in the 

 interior of the country. This fact proves that the beds of coal 

 and bituminous shale are not mere local deposits confined to 

 particular troughs or basins. They are interstratified with the 

 other beds, partake of their irregularities, and range with them 

 from the coast to the western limits of the district.f 



In the year 1821 a work was commenced in one of the lowest 

 beds at a part of the coast (called Brandy Hole) between Robin 

 Hood's Bay and Whitby. The section exhibited in the cliff was 

 as follows : 1. Alum-shale at the base of the cliff. 2. Ferrugi- 

 nous coarse grit (dogger). 3. Alternations of shale and grit 30 

 or 40 feet. 4. Thick beds of strong coarse sandstone. — Fine 

 specimens of pit-coal had been extracted from one of the shale 

 beds subordinate to No. 3. Similar works in the lower coal beds 

 had been attempted in some of the neighbouring parts of the coast ; 

 but I believe they have never been carried on in any part of the 

 interior of the district where the beds are less accessible, and 

 under such circumstances too thin to pay for working. 



Such are the leading characters of the great deposit which, on 

 the coast of Yorkshire, is interposed between the alum-shale 

 and the calcareous grit of the coral-rag oolite. As a mere 

 matter of convenience, the upper and lower portions may admit 

 of a separate description ; but the whole is so intimately linked 

 together that it must be regarded as one formation, to which 

 there is nothing strictly analogous among the beds of the same 

 age in the south of England.;}; 



• A small quantity of galena was found, by the authors of the " Survey of the 

 Yorkshire Coast," in Kome slender veins or crevices in the dogger near Whitby (see p. 

 194X 



+ It in stated in the " Survey of the Yorkshire Coast," (p. 1 1 8) that the best seams 

 which have been wrought are about seventeen inches ttiick, and the worst about six. 

 They are very liable to vary, and are often mixed with bituminous shale ; but in favour- 

 able instances, they yield a very bright pure bituminous coal. 



{ The whole thickness of the formation is very considerable, but appear! to vary in 



2a2 



