REPORT OF THE CHIEF ASTROXOMER 

 SESSIONAL PAPER No. 25a 



495 



cutting body in t every sense. Even where the contact line locally coincides in 

 direction with the strike of the sediments, as at the eastern end of the stock, 

 the dipping strata are sharply truncated by the granodiorite (Figure 36). 

 ^Moreover, the granodiorite v was not introduced by any system of cross-faults or 

 peripheral faults dislocating the sedimentary rocks. Owing to the special 

 attitudes of the latter, the strike end dip of the beds would be peculiarly 



Figure 35. — Map showing relations of the Castle Peak stock to the deformed Pasayten 

 formation. Strike and dip (in degrees) shown ; faults in broken lines. 

 Scale :— 1 : 115,000. 



sensitive to such dislocation. The. faulting actually displayed in the Cretaceous 

 beds is strike faulting and was completed before the granodiorite was intruded. 

 (Figure 35.) The igneous body is thus neither a bysmalith nor a chonolith. 

 The magma entered the tilted sediments, quietly replacing cubic mile after 

 cubic mile until its energies failed and it froze in situ. 



ISTot only so; the superb exposures seen at many points in the deep can- 

 yons trenching the granodiorite illustrate with quite spectacular effect the 

 downward enlargement of the intrusive body. At both ends and on both sides 

 of the granodiorite body the steep mountain cliffs exhibit the intrusive contact 



