188 Dr. Berger on the Geological Features 



8. Amygdalotdal Wacke. 



Colour varie^aLcd reddish or greyish brown ; fracture dull and 

 scaly ; soft, owing to seatite which occurs both in grains and in 

 larger disseminated concretions. 



It also contains radiated zeolite in considerable abundance, in 

 concretions of all sizes : and cubic zeolite has been found at 

 Benyavenagh, but is very rare. 



Chalcedony is likewise found imbedded in this rock, but is not 

 very common. 



9. Wood Coal 



Has been found in seams varying from two inches to four or five 

 feet in thickness, alternating with trap rocks near Ballintoy; associated 

 with the bed of wacke, underlying the upper columnar stratum in the 

 cliffs of Portnoffer on the east of the Giant's Causeway, at Killymorris 

 near the center of the basaltic area, and at Portmore and other places 

 along the eastern shore of Lough Neagh. At Portmore the beds 

 are said to exceed considerably in thickness the dimensions above 

 given. The texture of the wood is often remarkably distinct, and 

 indicates that it is a species of fir. It has even been asserted that 

 the roots and branches of the trees could be traced. 



The wood coal at Portnoffer has the exterior surface of some of 

 its fragments penetrated to a certain depth by small nests of augite 

 imperfectly crystallized. 



