ON THE CIRCULATION OF UNDERGROUND WATERS. 



81 



the various beds passed through, in the sections published and unpub- 

 lished, occurring in this area. The sequence is as follows, in descending 



order : — 



Max. thickness. 

 Upper gypseous marls 450 feet 



I 



Red sandstones and marls 

 Lower gypseous marls . 

 Saliferous beds, anhydrite and salt 

 Magnesian limestone 

 Red and grey sandstone . 

 Coal-measures . . . . 



1,117 

 279 

 267 



Mr. Bird points oat that a bed of anhydrite invariably forms the top 

 of the saliferons beds. It is worthy of note that the Zechetein of Saxony 

 contains rock salt alternating with anhydrite. Immediately over the 

 anhydrite is a bed known as the ' rotten marl,' which occasionally leads 

 to the collapse of the borings. 



A boring made at Oughton in 1827, published in the Sixth Report, is 

 stated to be unreliable, the coal noted as occurring being probably an 

 error. 



A boring at Greatham, a mile to the south of Onghton, has proved 

 the following section, communicated by Mr. Bird, bored at Marsh House, 

 Greatham, for the Greatham Salt Boring Company, Lim. : — 



Red 

 Sandstone , 

 and marls. "* 

 587' 6" 



Ft. in. 

 71 11 



579 3 



\659 5 



Lower 

 gypseous 



marls. 

 203' 7" 



1,803 



Saliferous 



beds. 

 109' 9" 



Drift 



Red sandstone .... 

 Red sandstone with beds of marl 

 Red sandstone .... 

 Red sandstone with beds of marl 

 Red sandy marl .... 

 Red marl with blue joints . 

 Red sandy marl .... 



Red marl 



Red marl with blue joints . 

 Red marl with veins of gypsum 

 Red marl, veins of gypsum, and 



blue joints .... 

 Red marl, veins of gypsum, and 



blue spots .... 

 Red marl with veins of gypsum 

 Anhydrite ..... 

 Red marl (rotten) 

 Rock salt ..... 

 Salt and anhydrite mixed . 



Rock salt 



Anhydrite 



The left-hand column gives the classification adopted by Mr. Bird 

 ('Trans. Man. Geol. Soc' vol. xix. part xx. p. 572), the column on th& 

 right that of Mr. Wilson, F.G.S. (' Quart. Jour. Geol. Soc' Nov. 1888). 



Ft. 



33 

 1889 



Boring at Seaton Carew, 18S7-89, from Mr. "W. J. Bird. 



Ft. in. 



Brown clay . 60. 



Red clay ■ . , .60 



Red pinnul and cobbles 9 }■ Drift. 



Soft red sandy marl 12 



Red sandy marl •.«. ••. . . .30' 



