Dr. Irving — On the Air oh Schists. 259 



of Mesozoic age (a position very far from established), a much more 

 rational account could be given of the garnets, etc., as derived 

 (allothigenous) minerals. 1 



The case seems to break down hopelessly, and with it this last 

 desperate sally of the upholders of the extreme orthodox doctrine 

 of the followers of Hutton and of his still more illustrious exponent 

 of our own time. Science truly hath its marvels ; and marvellous 

 it is to see this nineteenth century drawing towards its close, while 

 distinguished English geologists are « dealing blows in the air ' in 

 defence of their pet doctrine of ' uniformitarianism,' first propounded 

 by a most worthy and illustrious man, who lived and died when 

 modern chemistry was as yet in its infancy, when spectrum analysis 

 as applied to cosmical physics was not even dreamt of, when thermal 

 chemistry was unknown, and men like Joule had not done their 

 work and written their names on the muster-roll of Fame. 



Supplementary Note (Mat 1st). 



A great deal has been made of late in some quarters of the facts 

 described by Dr. Lawson (of the Canadian Survey) in his paper 2 

 published by the International Congress of London in 1888. It has 

 been proclaimed to the world that these afford evidence of an 

 igneous origin (igneous in the plutonic sense) of the Laurentian 

 gneisses. And yet, strange to say, they do not perceive that this is (if 

 not an utter capitulation) a surrender of the greater half of the field 

 by the metamorphic school. They are recognized in fact as being 

 crystallized portions of the original magma, which was once sub- 

 jacent to the earlier and thinner crust (the schists). I do not mean 

 to say that this is admitted in so many words ; but substantially it 

 is admitted. I saw this very plainly in September, 1888. I com- 

 municated my ideas to Dr. Lawson in conversation ; and in a 

 footnote to page 68 of my "Chemical and Physical Studies," 1889, 

 I gave this as a direct deduction from the principles of metataxis 

 contended for in that work. I pointed out that, " As the outer 

 zone of the lithosphere solidified through the dissipation of energy 

 by radiation, the tidal movements still continuing, huge masses 

 (even ' regional ' masses) of the solidified outer ; crust ' would slide 

 over the viscous magma beneath, as the strain produced by tidal move- 

 ments in the latter caused huge fractures here and there in the crust. 

 As the magma grew more and more viscous, it is certain that under 

 such circumstances huge fragments of the thin crust would be torn 

 away, imbedded in the magma, and transferred in some cases to 

 considerable distances. This seems to be the most natural explana- 

 tion of the striking facts observed by Lawson in the Laurentian 

 gneiss, and described by him in his Essay." 



The facts referred to are set forth in much fuller detail in the 

 Official Report since published, which is a very fine piece of work, 

 as I know, from the copy which Dr. Lawson has been good enough 

 to send me. Since the publication of that Report, Dr. Lawson has 



1 See Chemical and Physical Studies, etc., Appendix II. note T. 



2 Vide Eludes sur les Schists Crystallins, pp. 66-88. 



