J. M. Clements — Study of Contact Metamorphism. 87 



Analysis of Spilosites. 



1. 2. 



Si0 2 ... 52-51 57-77 



Ti0 2 1-70 -92 



A1 2 3 19-00 19-35 



Cr 2 3 none none 



Fe 2 3 .... 3-31 1-29 



FeO... 719 3-37 



MnO trace trace 



CaO _ 1-55 1*71 



BaO._ trace none 



SrO . . trace trace 



MaO 3-29 4-35 



K 2 0___ -70 -22 



Na 2 6-72 8-22 



Li 2 G trace none 



H 2 OatlL0° -34 -18 



H a O above 110° 3-26 2-34 



P 2 6 -15 -04 



C0 2 _. none none 



S and S0 3 none none 



C* 



CL none none 



F trace none 



Total 99-72 99-76 



No. 1, Spilosite, Spec. 32«61 Lake Superior Division U. S. Geol. 

 Survey, from Mansfield, Michigan, Dr. H. N. Stokes, analyst. 



No. 2, Spilosite, Spec. 32827 Lake Superior Division U". S. Geol. 

 Survey, from Mansfield, Michigan, Dr. H. N. Stokes, analyst. 



Desmosites. — Under the desmosites are included contact 

 products composed of the same mineral constituents as the 

 spilosites, but which instead of being spotted show a distinctly 

 banded structure. That these are very closely related to the 

 spilosites, and that in fact they grade into each other is shown 

 by the study of one rock. A section from this, examined 

 under the microscope, shows irregularly rounded areas which 

 consist of ragged bunches of chlorite and aggregates of rntile 

 and epidote, with some flakes of biotite lying in a quartz-feld- 

 spar mass. As these spots increase in number they approach 

 each other and unite, forming streamers which in their turn 

 unite and form bands. No analysis has been obtained of the 

 desmosites, as it was so evident tfiat they contain nothing dif- 

 ferent from the spilosites. 



Adinoles. — Thus far chlorite has been the chief dark constitu- 

 ent of the contact products mentioned, whereas actinolite is 



* C was not determined. 



