534 



OGILVIE 



The latter develop very conspicuous contact zones of actinolite 

 along the borders. The dikes are all small, usually three inches 

 or less in width, and they are not of great length. On the same 

 island are many large granitic dikes, microscopically similar 

 to the lassenose, which are thirty feet or more in width. These 

 granite dikes are entirely distinct from the sitkose. Mega- 

 scopically the latter seems to contain primarily pink feldspar 

 and actinolite. 



Comparison with Alaskan Sitkose. — It is worthy of note that 

 in the only other known locality where this subrang is found, 

 namely in the neighborhood of Sitka, Alaska, the field relations 

 are described * as being essentially similar to those above in- 

 dicated for Fisherman's Island. In both cases the dike rock is 

 involved with sediments in a way that seems deceptively like 

 bedding, and in both there is a crushing of the quartz on a 

 microscopic scale. The essential differences between the two are 

 the much higher lime content of the Maine rock and the dynamic 

 metamorphism of the whole Maine region at a time subsequent 

 to the intrusion of the dike. The analysis of the Sitka rock is 

 here reproduced for comparison. 



Table V. 





Analyses, 



Molecular Proportions and Norms 



of Sitkose. 





Composition. 



■ 

 Molecular 

 Proportions. 



Norm. 





I. 



II. 



I. 



II. 





I. 



II. 



Si0 2 



67.04 



65-94 



1. 117 



I.O99 



Qu 



28.68 



30.1 



A1 2 3 



11.40 



13-74 



.112 



■134 



Or 



6.12 



10. 



Fe 2 3 



.78 



•49 



.005 



.003 



Ab 



23.06 



23.6 



FeO 



3-75 



5-21 



-051 



.071 



An 



I5-85 



14.2 



MgO 



3-52 



2-33 



.088 



.058 



C 





2.0 



CaO 



7.60 



2.87 



.136 



•05I 



Di 



16.96 





Na,0 



2.70 



2.80 



.044 



■045 



Hy 



3-96 



13.6 



K 2 



1. 00 



1.63 



.Oil 



.Ol8 



Mag. 



1.66 



• 7 



H,0 + 



.16 



2-59 







Ilm 



3-!9 



i-5 



H 2 0- 



.09 



.21 







Ap 



•34 





C0 2 



none 



•59 













Ti0 2 



1.68 



.80 



.021 



.OIO 









P 2 O s 



.12 



.21 

 99.41 



.OOI 



.002 









Total 99.84 





1 Becker, Annual Rept. U. S. G. S., XVIII, Pt. Ill, p. 43. 



