BY W. N. BENSON. 127 



individual masses are separated, as usual, by narrow bands of 

 epidote, etc., and quite large crystals of quartz or epidote may 

 occur in the cuspate cavities between several pillows; no radio- 

 larian chert has been observed in such a situation, though it 

 occurs in this manner in several British localities. Occasionally, 

 the pillow-lavas are invaded by massive non pillowy dolerite, 

 which sometimes has chilled marginal zones. 



Pillow-structure may also be observed on the cuttings on the 

 Hanging Hock road, though greatly obscured by spheroidal 

 weathering. The spilites are here intersected by a dyke of horn, 

 blende-lamprophyre. The exposures on Oakenville Creek, just 

 to the south of the road, are almost entirely covered with drift ; 

 one exposure, however, shows a most intimate mixture of spilite 

 and chert. Fig. 1 was traced from a flat-ground surface of a 



Text-fig. 1. — Spilite intrusive into radiolarian clay. 

 (Nat. size). 



specimen obtained from here. The microscopical character of the 

 entangled chert suggests that, in this case, it is largely, if not 

 entirely, the product of infiltrations subsequent to the consolida- 

 tion of the igneous rock. Such is believed by Messrs. Reynolds 

 and Gardiner* to be the origin of the strings and patches of 

 chert in the spilites of Kilbride Peninsula, County Mayo, Ireland. 

 Another important mass of pillowy rock commences nearly a 

 mile further up Swamp Creek than the point where the first zone 

 crossed, and continues thence up the gorge to the falls. It 

 * Quart. Journ. Geol. Soc, 1912, pp.80-81. 



