28 baker's north YORKSHIRE. 



series has a total thickness of i,ooo feet, the beds being con- 

 glomeritic below and more laminated and more interpolated 

 with clays as we proceed upward. In our own field of study 

 these sandstone beds may be seen in quarries at Ripon and 

 Boroughbridge, and in the bed of the Tees about Croft. In 

 two or three places in the vicinity of the Tees they have been 

 partially sunk through in fruitless attempts at boring for coal. 

 At Dinsdale they were excavated to a depth of 450 feet, and 

 opposite Sockburn to a depth of 700 feet without the Magnesian 

 Limestone being reached. Here the strata were found* to con- 

 sist of white, grey or reddish sandstones, with occasional partings 

 of a more compact nature, red or blue shale, carbonaceous 

 matter in thick layers and gypsum in nodules or beds. In one 

 case a bed of gypsum was found which was three feet in thick- 

 ness. In sinking for the foundations of the North Eastern 

 railway bridge over the Swale, solid sandstone was reached on 

 the west of the river but not on the east. 



The Keuper, or upper, part of the series consists principally of 

 red marlstones, which in Cheshire are 700 feet in thickness, and 

 in North Yorkshire may be seen in the Howardian district and 

 about the Tees estuary. In Nottinghamshire they form the 

 subsoil of the claylands of the eastern part of the county, 

 their escarpment being visible in a well-defined chain of low 

 hills, which crosses the great north road above Markham Moor. 

 The beds sink gradually beneath the glacial deposits of the 

 great plain which is drained by the Trent. 



RhcEtic Beds. — In North Yorkshire, as nearly everywhere 

 in England along the junction of the Keuper marls and Lower 

 Lias, these thin but remarkably constant ' passage beds ' have 

 been detected. Fifteen feet of shales, with sandy beds, rest 

 upon some ten feet of blue or tea-green marls. They are not 

 exposed along the coast, but at Lazenby, S.E. of Redcar, near 



* The complete sections as reported by the miners engaged in these 

 excavations were given by the late Mr. Winch, in the fourth volume of the 

 Transactions of the Geological Society. 



