210 Mr. Hutton on the Stratiform Basalt. 



The other instance is the section below Cauldron Snout (Plate 9, Fig. 

 5, vol. ii. Cambridge Phil. Trans.), where the Basalt is seen crossing 

 the edges of several inclined beds of Limestone, &c. I confess there 

 is a difficulty here, but if we may be allowed to suppose any sinking 

 or movement of the inferior part of the formation prior to the deposition 

 of the higher, such an appearance as is exhibited will become perfectly 

 natural. 



Professor Sedgwick's other conclusion as to the Geological period 

 when this injection of Basalt took place, viz. prior to the deposition of 

 the Magnesian Limestone, is founded upon the idea that the Basaltic 

 Dykes of Northumberland and Durham do not pass through that 

 rock. 



In that which he himself first described (See Camb. Phil. Trans, vol. 

 ii., page 40) as passing from Bedburn Beck by Hett, &c, to Quarring- 

 ton Hill, there is no doubt this is the fact, but all that can be said of 

 the well known Dyke below Tynemouth Castle in Northumberland is, 

 that it is not seen in contact with the Magnesian Limestone, but that 

 it completely cuts through the subordinate bed (the lower New Red 

 Sandstone), which belongs to the same formation, and is interstratified 

 with that rock close to the Dyke, is certain. t 



In the great Cockfield Dyke also, which there can be little doubt is the 

 same, which pierces the superior formation in Cleveland, although it 

 cannot be seen in contact with the Magnesian Limestone (that rock 

 itself being no where visible), it may be seen cutting directly through the 

 same bed (the lower New Red Sandstone), in a Quarry near Heighington, 

 in the County of Durham. According to this idea, the period of the 



portion of Lunedale is in an extremely confused state, the beds being apparently broken to 

 pieces and raised up in detached masses, in such a manner as to make it difficult to conjec- 

 ture what the cause could be. About a quarter of a mile above Saddle Bow the confusion 

 ceases, and here a Whin Dyke may be seen by the side of Carlbeck, cutting through the 

 strata without disturbance. This Dyke runs in the direction of Saddle Bow, but is not 

 likely to have broken the strata, in the lower part of the valley as before conjectured, as it 

 may be traced for several miles up Lunedale, occasionally at the surface, without causing any 

 other disturbance than a slip, or throw, of 6 fathoms, down to the north. W. H. 



-j- See vol. i. page 67. 



