REPORT OF THE CHIEF ASTRONOMER 



363 



SESSIONAL PAPER No. 25a 



the Rossland volcanics and the Sophie Mountain conglomerate. These have 

 rather constant characters and for them also the description of the one, the 

 chonolithic rock, will suffice. 



Chonolith. — Just north of the Boundary slash at Monument 169 a relatively 

 large tody of the porphyry cuts the Rossland volcanics and the overlying con- 

 glomerate which has been described on a previous page. The form of the body 





1000 



_l 



Feet 



HORIZONTAL AND VERTICAL SCALES 

 Figure 24. — Section of syenite porphyry chonolith, satellitic to Coryell batbolith. 



is highly irregular, though there is little doubt that it is an injected mass, 

 thrust into the invaded formations, much as a dike is injected. The body is. 

 thus, probably, a chonolith, rather than a stock or other subjacent body which 

 enlarges downward indefinitely. Figure 24 gives a diagrammatic profile-section 

 of the chonolith, the roof of which is still partly preserved. The rock of the 



