EXPLANATION OF THE PLATES, 



PLATE 1. 



Map of Northumberland and Durham, to illustrate Mr. Winch's paper. 

 ,The colouring- points out the different rocks. The contact of that series called 

 the Leadmine measures or Mountain limestone with the red marl or sand- 

 stone to the westward of Temming towards Brampton is not accurately 

 ascertained, but a little to the south-east it has been traced by Professor 

 Buckland from Melmerby to Murton, and is laid down in the map accom- 

 panjing- his paper (Plated.) The letters U and D, placed against the com- 

 mon slip djkes of the coal measures denote that the strata are elevated or 

 depressed on that side by the number of fathoms marked after the letter. 



PLATE 2 



Js a figure of the fossil Fish, apparently belong'ing to the genus Chcetodon, 

 found in the magnesian limestone at Low Pallion, as mentioned in page 9. 



PLATE 3. 



Is a plan, communicated to the Society by Mr. Hill of Newcastle, of the Dyke 

 in Walker Colliery, taken at the level of the High Main Coal, 100 fathoms 

 from the surface. The sectional lines, AA and BB, mark the situation 

 of horizontal drifts that hav^e been cut through the dyke, the particulars of 

 which are given in page 22. 



PLATE 4. 



Fig. I. Shows the manner in which the magnesian limestone overlies the Coal 

 measures at Whitley quarry near Cullercoats. The ninety-fathom Dyke ig 

 seen passing through the Coal measures, and the limestone appears de- 

 posited in a hollow or trough upon them in a manner that shews it to be 

 of a subsequent age, as the former are much dislocated by the dyke, while 

 the latter is not at all disturbed. See page 4. 



Fig. 2. Is a sectional view of the Dyke at Walbottle Dean, described page 23 



