8 



THE GEOLOGIST. 



The section at the Chiinney-heaclland is as follows : commencing 

 at the top, two thick beds of columnar basalt, closely resembling 

 each other in appearance, a few columns of the top one being left 

 standing apart from the main mass at the edge of the clifP, thus sug- 

 gesting the idea of the " chimney ;" the floor of the upper bed is re- 

 markably level. These columnar basalts rest on what is known as 

 the great ochre bed — a well marked feature in the section. Below 

 this ochre layer the remainder of the cliff consists of possibly four 

 deposits of amorphous basalt, each separated from the other by a 

 thin layer of ochre. 



In the lesser headland, east of Portnoffer Bay, the section is very 

 similar to that just described; the two upper columnar beds are 

 again recognized, and together rest on the ochre bed, which here, 

 however, has become considerably thinner, and, owing to a steady 

 dip of about five degrees to the west in all the beds at that side of the 

 Chinmey-head, it is now much nearer to the sea than before ; this 

 may be the result of a slight upheaval en masse of the beds at the 

 Chimney -headland. 



Lign. 5.— The "Organ." 



If we attempt to follow the great ochre bed towards the Cause- 

 way, or in its western extension, it appears to tliin out, and to 

 be easily concealed by the debris from the cliffs above, and 

 eventually a very marked change is observed in the superimposed 



