THE TRANSVERSE VALLEYS. 227 



such agency as ice. He does not attempt to explain just what were the 

 pecuHar conditions that enabled this great mass of bowlders, in which there 

 are many thousands weighing from twenty to one hundred pounds and 

 occasional examples of several thousand pounds weight, to be trans- 

 ported, often several hundred miles and deposited over the bottom of this 

 sea. Nor does he cite any similar deposit now forming at the bottom of 

 the sea as proof of the truth of his dictum. Instead, however, he com- 

 mences the succeeding paragraph on "The Transverse Valleys of Pata- 

 gonia" and continues thus: 



"Having dispelled the ignorance [italics mine] as to the origin of the 

 Bowlder (Shingle) formation, this leads us naturally to determine the age 

 of the transverse valleys of Patagonia. It is evident that at the bottom of 

 the ancient sea in which the bowlders were deposited, these were scattered 

 by the waters in a uniform manner over all the submerged territory. The 

 same may be said of the sheets of basalt ; these also must have extended 

 in a comparatively uniform manner, without forming the steep cliffs which 

 they exhibit to-day in the river valleys. Darwin, speaking of the scarps 

 of the valley of the River Santa Cruz, said that the cliffs of basalt of the 

 two opposite sides were recognizable immediately as at one time forming 

 a continuous bed. The same may be said of the beds of bowlders which, 

 in many parts, form the opposite cliffs of the Patagonian valleys ; those 

 beds were continuous across the valleys, but there are now no traces 

 of them. 



"It is evident that if the valleys had existed before the great marine 

 submergence referred to, they would have been completely filled with 

 marine deposits, which, even supposing they had been swept away after- 

 wards by the waters, would always have left numerous traces buried in 

 the innumerable angles of the slopes ; but as such deposits do not exist, 

 the inevitable conclusion is, that the formation of the great transverse 

 valleys of Patagonia was brought about by great dislocations and gigantic 

 faults at a comparatively recent geological period, posterior to the Bowlder 

 (Shingle) formation and at the last emergence of the land." 



Why does not Dr. Ameghino in this connection cite an example of 

 one of these gigantic faults and give its geographic position, for the benefit 

 of future students who may visit Patagonia and be desirous of determin- 

 ing for themselves the nature and amount of such dislocation ? Moreover, 

 I should like to enquire as to just how Dr. Ameghino proposes to har- 



