NOIJTHUMJJKKLAXI) AND DURHAM. 237 



Loc. Tynemonth, North Point to the south of Mai-Kdeii Bay; 

 coast between Ryhope, and Castle Eden Dene; BLack Halls; 

 banks of the Wear above Sunderland Bridge; Tunstall Hope. 



The Shell-Limestone, forming the westernmost or basseting 

 portion of the above deposit, is an irregular mass of highly 

 crystalline limestone, in some parts exceedingly hard and fine- 

 grained, and in others friable, earthy and ruljbly, consisting of 

 broken pieces of coral and shells. It contains an assemblage of 

 the most characteristic fossils of the system. When seen in 

 section it generally rests on the Compact-Limestone, but at 

 Clack's Heugh, it rests also on a bed of friable sandstone. 



The thickness, owing perhaps to denudation, is not more than 

 50 feet. 



Char. Foss. — Terehratula elongata, Schloth. ; Camarophoria 

 Schlotheimi, v. Buch; Spirifer alatus, Schloth. ; Strophalosia 

 Goldfussi, Miinst. ; Productus liorridus^ Sow.; Fenestella reti- 

 formis, Schloth.; F.virgidacea., Phill., &c. 



Loc. Down Hill, near West Boldon, Hylton Castle, South - 

 wick Red House, Clack's Heugh, all on the escarpment. High 

 Barns, Humbleton Hill, Elstobs, Tunstall Hill, liyhope Field 

 House, Dalton-le-dale, Castle Eden Dene. These places are 

 situated on the middle portions of the Magnesian Limestone. 

 At Black Halls it occurs in the form of an interstratified 

 conglomerate. See Sect. Geol. Trans.., II. ser,, vol. iii., pi. 7, 

 f. 5, D. 



Lower. 



4. Compact-Limestone and Conglomerate. — In most places 

 on the escarpment the Compact- Limestone forms a very thick 

 deposit of thin-bedded, compact, bluish grey or mottled lime- 

 stone, becoming occasionally brown, earthy, cellular, and with 

 thicker beds towards the top. 



It attains a thickness probably of 150 to 200 feet. 



Char. Foss.— Same as in shell-limestone, but not so abun- 

 dant. 



Loc. Whitley, Cullercoats, Tyneniouth, outliers; from North 

 Point to Man Haven, surmounted by Cellular- Limestone ; 



VOL. III. PT. IV. 1 F 



