BY W. N. BENSON. 



129 



No very definite statement is possible with regard to the other 

 masses of spilite mapped, since their boundaries are rarely ob- 

 servable. It seems safest to consider them, also, as intrusive, 

 whether they are vesicular or not, when there is no evidence to 

 the contrary, and particularly when the rock is not pillowy, and 



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 a 



the texture is not more than subvariolitic. Even highly variolitic 

 rocks have been proved to be intrusive. On such negative evi- 

 dence, we may class as intrusive spilites or amygdaloidal dolerites, 

 the bands shown on Moonlight Hill, tliose on the western side 



