FRAXKLIX FURXACE MIXETTE 



379 



evident that there is a sharp flexure at about 390 millimeters. We have 

 for the average slope of the two sides between 76 and 180 millimeters, 

 s = .000575. We can not determine whether this slope is A with a con- 

 tact zone of 87 millimeters and 2o/Uo = .22, or whether the contact zone 

 is grea^ter and this Cand ujUo is .785. The apatite increases clear to the 

 center, and the question then arises whether this is due to the fact that 

 it is formed at the earlier stage of cooling — earlier than the mica — or 

 whether it, as the apatite at Marquette, is affected b}^ a process of segre- 

 gation. The fact to which Queneau calls attention, that the crystals, 

 although they vary in size relative to the margin, are fractured, would 

 indicate that they were formed at an early stage, and that a little motion 

 in the viscous magma took ])lace afterward. 



Apatite from the Mineite Dike 



Distance. 



Difference. 



Dimensions. 



Difference. 



Ratio of 

 difference. 



00 





.0264 







76 



76 



.0490 



.0226 



.000297 



180 



104 



.0750 



.0260 



.000250 



380 • 



200 



.0877 



.0127 



.000063 



1020 



640 



.1590 



.0713 



.000110 



3050 



2030 



.2440 



.0850 



.000040 



6100 





.0360 







6030 



70 



.0550 



.0190 



.000271 



5920 



110 



.0830 



.0280 



.000254 



5710 



210 



.0825 



.0005 



.000002 



4880 



830 



.1070 



.0245 



.000029 



3050 



1830 



.2440 



.1370 



.000074 



Biotite Mica 



00 





.083 







76 



76 



.130 



.047 



.000618 



180 



104 



.187 



.057 



.000548 



380 



200 



.213 



.026 



.000130 



1020 



640 



.298 



.085 



.000130 



3050 



2030 



.324 



.026 



.000012 



6100 





.0550 







6030 



70 



.0850 



.0300 



.000428 



5920 



110 



.1510 



.0660 



.000600 



5710 



210 



.2790 



.1280 



.000609 



4880 



830 



.3260 



.0470 



.000056 



3050 



1830 



.3240 



.0020 



.000001 



