18 A NEW FLOKA OF 



extends westward from CuUercoats, the Coal Measures have 

 been thrown down on the north side from 500 feet to 1000 feet. 

 Probably, too, the effect of the Penine upheaval has extended 

 further northward into ISTorthumberland, though without pro- 

 ducing any gTeat break in the strata in the direct line of action ; 

 for the general direction of the strata is from north to south. 

 There are many other smaller displacements of the Coal Measures, 

 but the Mountain Limestone strata are even more disturbed by 

 faults : one seen in the Shilbottle colliery, ranging from east to 

 west, throws down the beds on the south side 120 feet; another 

 great fault near to Annstead, going westward, throws the strata 

 down on the north side about 1000 feet. 



IV. PERMIAN FOliMATION. 



Of this formation only one member, the Magnesian Limestone, 

 appears in our district. It was usual to group with it an irre- 

 gular, loose, sandy deposit, and some red sandstones lying below 

 it ; but the discovery of several true Coal Measure plants, such 

 as Pinites Brancllingi, Trigonocarpon Noggerathi, Calamites ap- 

 proximatus, and Sigillaria reniformis, in these sandstones, at 

 Tynemouth, and of Neuropteris gigajiica, Sphenopteris latifoUa, 

 &c., in the shales connected with them, shows that these red 

 sandstones should be grouped with the Coal Measures, the place 

 assigned to them by Dr. "William Smith, the father of English 

 geology. Mr. Howse, in 1857, proposed, that they should be 

 considered as the uppermost members of the Carboniferous for- 

 mation, with which they are seen to be conformable in the sec- 

 tion on the coast at Tynemouth. 



The Magnesian Limestone occurs in IN'orthumberland in three 

 small patches overlying the Coal Measures; one at Tynemouth 

 forming the top of the cliff, and the others at CuUercoats and 

 Whitley, where it has been preserved by the Ninety -fathom 

 Dike, which has thrown down the strata on the north. It oc- 

 cupies in Durham a large space, somewhat triangular in shape, 

 one side extending from South Shields along the coast to Hart- 

 lepool, the other having a wavy line from the same point to 



