Fingal and East Coast. 49 



The uppermost seara, of the three yet discovered at 

 this locality, presents itself about 200 yards higher up 

 the most easterly of the two creeks, and probably about 

 200 feet in vertical altitude above the main seara. It is 

 3^\ feet thick: ther€ is 18 inches of schistose clay, suc- 

 ceeded by sandstone, over it; and there is black shale, 

 succeeded by clay and thin sandstone, under it. The 

 seam contains, at six inches from the bottom, nine inches 

 of shale ; and the rest of it, though very carbonaceous, 

 cubical in structure, and bituminous, is not a superior 

 coal. 



The lower seam of the three shows itself at about 50 

 feet of vertical depth below the main seam. It is 2^\ 

 f^et thick, and dips to E.N.E. at about 1 in 20. The 

 greater part of it is mixed up with black shale and schis- 

 tose clay to such a degree as to render it valueless. This 

 clay is replete with impressions of ill-defined leaves, &cc. 

 of plants. 



The aggregate thickness of the beds of sandstone, 

 shales, and clay, exposed between the culminating heaps 

 of greenstone above and the solid masses beneath, may 

 be about 400 feet. 



It appears that, at the upheaval of the greenstone pla- 

 teau first mentioned, the eruptive rock forced its way 

 laterally at some points between the carboniferous sand- 

 stone and the crinoidal limestone, carrying the former 

 up with it, and spreading in overlying masses in the 

 valley below : that it at length burst through the stra- 

 tified rocks above, and overflowed them to the depth of 

 several hundred feet ; its molten matter acquiring, in 

 the process of slow cooling, the semi-crystalline struc- 

 ture now presented by its aggregated masses of columns, 

 cones, and prisms. 



A line carried nearly south from the outcrops of the 

 coal mentioned will, at a distance of about two miles, 



E 



