16 TRANSACTIONS OF THE [oCT. 14, 



tion, and hence is a favorite realm for the geological theorist, 

 where the processes evolved from his inner consciousness are safe 

 from the rigorous tests of observation. 



On these accounts, the suggestions of this paper are presented 

 only after much hesitation, and solely as a contribution to the 

 general discussion of the subject, as indicating certain lines of 

 inquiry and observation by which their ultimate value may be 

 proved or disproved. 



Certain great facts in the process of world-building stand out 

 undisputed and unchanged, while our theories as to their origin 

 are constantly varying, and, we may hope, advancing nearer to 

 the truth. [Various points of recent discussion were cited here 

 in illustration.] 



There is one remarkable body of facts, to which but little atten- 

 tion has been given by geologists, and for which, so far as I am 

 aware, no cause has been clearly assigned. Yet the facts are so 

 striking and important that this omission seems singular, amid 

 all the theories and discussions of crust-structure. I refer to 

 the system of diagonal trends which is so marked in the geography 

 of the globe. 



The fact has been long observed, and often alluded to by phy- 

 sical geographers, that the continents and islands are largely 

 adjusted upon two great systems of lines having a general 

 N.E.-S.W., and N.W.-S.E. direction respectively. Prof. Dana 

 devotes to this subject a brief but very interesting and sugges- 

 tive chapter in the opening portion of his " Manual of Geology." 

 But, in general, the fact has been merely referred to, and no 

 cause recognized or proposed for its origin. 



If it be true, however, that there is such a principle of struc- 

 ture underlying and determining the form and disposition of 

 the land-masses, we are confronted with a fact of the widest and 

 most important significance, and one that may well challenge at- 

 tention and inquiry. 



As to the form and distribution of the land-areas, we know of 

 course that the continents are growths, — that they have had a 

 history in which, as in other histories, each stage of develop- 

 ment is the outcome of previous conditions, and that so their 

 existing form and structure have resulted from features very 

 early outlined. [This subject was treated of briefly, with par- 

 ticular reference to the recent paper of Prof. Dana before the 

 American Geological Society, at Toronto, reaffirming his gen- 

 eral doctrine on tliese points.] Prof. Dana has given us the term 

 protaxis, as a happy designation for those early lines of uplift 

 which have determined tlie subsequent growth of mountain-sys- 

 tems, and by these again the shaping of continental masses. 



But the problem of the origin of diagonal trends goes further 



