Mr. Tate on the Geology and Archoeoiogy of Beadnell. 107 



of level ; as many times, during the period when these rocks 

 were deposited, was the district clothed with an abundant and 

 marvellous vegetation — as many times were there alternations 

 of swamps and lakes, of estuaries, of lagoons, and of seas 

 sometimes profound, but generally of moderate depth. 



LEAD VEIN. 



A little northward of the basaltic dike, a narrow crack or 

 fissure of the sandstone contains Galena or Sulphuret of Lead. 

 It runs across the strata from south by east to north by west ; 

 and a branch from it forks off to the north-north-west. The 

 vein seems too small to be worked with advantage. Its posi- 

 tion gives probability to the theory that the igneous agency 

 which forced upward the basalt, produced also, by sublima- 

 tion, the ore which is found in the vein. 



BASALTIC DIKE. 



When viewed from the shore near to Dunstan Square, 

 this basaltic dike, even to one unacquainted with geological 

 principles, is a striking and interesting object. It rises per- 

 pendicularly through the stratified rocks, and runs in a direct 

 line from west 85** south to east 85° north. Its width is 

 25 feet, but contracting seaward to 20 feet. It stands in 

 some parts ten feet above the strata, and appears like a wall 

 rudely piled up by Cyclopean builders ; and though, in other 

 parts, it is broken down by the waves, its course can be dis- 

 tinctly traced for a considerable distance into the sea. The 

 basalt is of the usual composition, augite and felspar, but 

 finer grained than the larger masses at Ratcheugh and the 

 Fame Islands. The adjacent strata are very slightly altered 

 in position; but their structural characters are changed. 

 Coal for some distance from it is valueless ; limestone near to 

 it will not burn into lime ; and shale and sandstone are in- 

 durated. Besides, at the point of contact, sandstones, shales, 

 and limestones are much jointed and fissured, and assume the 

 external form of basalt ; and on the other hand, the basalt 

 itself becomes calcareous and siliceous. This transference of 

 qualities and the structural changes superinduced are the re- 

 sults of the igneous agency which, by its upward pressure, rent 

 asunder the vast mass of stratified rocks, and then poured the 

 molten basalt into the fissures. 



ARCHEOLOGY. 



On the narrow rocky point of Ebbs Nook, overlooking the 

 sea, stood a humble religious edifice ; which, however, so long 



