18 TRANSACTIONS OF THE [OCT. 14, 



motion is thus produced, which causes in the one direction frac- 

 ture by extension, and in the other ridging by compression. 



I suggest, therefore, that as soon as a continuous crust began 

 to form over the globe, tliere must have been a constant tendency 

 to the production of a system of fractures and a system of ridges, 

 the former trending in a general way parallel to the direction of 

 the trade-winds, and the latter intersecting them at right angles. 

 This phraseology is used, as briefly expressing the courses that 

 must otherwise be described in much more extended wording, 

 unless we adopt special terms for the purpose. 



The latter course is probably the best, however, as the com- 

 parison with the trade-winds is liable to confusion. 1 will there- 

 fore propose the term Eoclinal to denote the courses inclining 

 toward the east in passing from the poles toward the equator, 

 and Hesperoclinal for those inclining toward the west, equator- 

 ward, — or, as I expressed it, lying parallel to the course of the 

 trade-winds. 



The increasing eastward velocity of rotation in the lower lati- 

 tudes will, I claim, place the crust in a condition of twofold 

 horizontal strain, and tend to develop a series of eoclinal ridges 

 of compression and hesperoclinal lines of extension, fracture, 

 and igneous outflow. By such a process, acting in the earliest 

 periods of crust-formation, I suggest that a double system of 

 diagonal trends would have been produced, determining the 

 general course of those primal or protaxial lines on which, by a 

 long succession of subsequent movements, the land and water 

 areas of the globe have been shaped. 



It will, of course, be objected to this view, that there is no 

 such uniformity and simplicity in the character and distribution 

 of fold-systems and fault-systems as would result from the pro- 

 cess thus suggested. This objection would be valid if the theory 

 asserted that such is the mode of formation of the present 

 features of geographical and geological structure; but it regards 

 the latter only as secondary and derivative — in many cases re- 

 motely derivative — from very ancient systems of disturbance and 

 displacement, of which the direct evidences and results have 

 long since been obscured, modified, or removed. 



I would here suggest, as extremely desirable, a much more 

 careful and minute attention than has heretofore been given, to 

 the detailed structure of the earliest lines of uplift and faulting 

 that are known to us. It may indeed be that even these will 

 fail to confirm strongly the view here presented, which would 

 then become purely theoretical and incapable of absolute proof 

 or disproof. In this respect, however, it would be no worse than 

 many theories propounded and advocated by much more accom- 

 plished geologists. 



