J. M. Clements— Study of Contact Metamorphism. 89 



contact, while the spilosites (and desmosites) are intermediate 

 between them and the clay-slates. The following series of 

 analyses are arranged in the order of approach to the dolerite, 

 as determined by the character of the rocks : 



1. 2. 3. 4. 



Si0 2 ._ 60-28 52-51 57*77 74-16 



Ti0 2 - -69 1-70 -92 -37 



A1 2 8 22-61 19-00 19-35 11-85 



Cr 2 3 none none 



Fe 2 3 ___ .._ 2-53 3-31 1*29 -82 



FeO -45 7-19 3-37 1-66 



MnO _ _ trace trace trace -06 



CaO -13 1-55 1-71 2-10 



BaO -04 trace none none 



SrO trace trace 



MgO 1-35 3-29 4-35 2'10 



K 2 0_._ _ 573 -70 -22 -15 



Na 2 0__ -54 6-72 8'22 6'57 



Li 2 . trace none 



H 2 at 100° - -60 *-34 * -18 -05 



H a Oatl00°+ 3-62 f 3-26 f2*34 e 52 



P 2 6 -03 -15 -04 -08 



C0 2 ._ _ none none none -09 



SandS0 3 __ none none 



C -97 -18 



CI _ . none none 



F trace none 



Total 9957 99-72 99*76 100'76 



No. 1, Clay-slate, Spec. No. 32497 L. S. D., TJ. S. G. S. Analyst 

 Mr. Geo. Steiger. 



No. 2, Spilosite, Spec. No. 32861 L. S. D., U. S. G. S. Analyst 

 Dr. H. N. Stokes. 



No. 3, Spilosite, Spec. No. 32827 L. S. D., U. S. G. S. Analyst 

 Dr. H. N. Stokes. 



No. 4, Adinole, Spec. No. 32465 L. S. D., U. S. G. S. Analyst 

 Mr. Geo. Steiger. 



In these analyses the usual increase of silica as the dolerite is 

 approached is at once noticeable, and hand in hand with it 

 goes the diminution in percentage of alumina and iron oxides. 

 The content of water and carbonaceous^: matter also suffers 

 diminution, as was to be expected. 



The most noteworthy difference between the clay-slate and 

 the contact rocks is shown in the relations of potash and soda. 

 This is well brought out in an examination of analyses Nos. 1 



* H 2 at 110°. f E *° above 1 10°. 



\ The C in Nos. 2 and 3 was not determined. 



