Volume XIII 



Number 6 



THE 



Journal of Geology 



A Semi -Quarterly Hagazine of Geology and 

 Related Sciences 



SEPTEMBER-OCTOBER, igo 5 



EDITORS 



T. C. CHAMBERLIN, in General Charge 



&i)e eanibetsitg of €f)icago ^ress 



CHICAGO AND NEW YORK 

 William Wesley & Son, London 



