504 Mark Stirrup — Recent Changes of Level. 



Examples, such as those that I have cited, might readily be drawn 

 from other localities, showing periods of repose and gradual growth 

 rather than a sudden or rapid sinking of the land ; and proving the 

 utter fallacy of the doctrine which these sunken forests are presumed 

 to support, — of a sudden or rapid sinking of the ground at that 

 vague and mysterious date, the close of the Mammoth period. 



After a quest over Europe and Asia in search of evidence for 

 great uplifts of land and their complementary depressions, Sir Henry 

 turns his attention to America, and in the ancient channels, now 

 submerged beneath the sea, of rivers like the Mississippi, the 

 Hudson, and the St. Lawrence, he finds so-called examples of the 

 great catastrophe for which he is pleading. 



He quotes extracts from papers by Professor J. W. Spencer and 

 other well-known American geologists with regard to stupendous 

 continental elevations and great subsidences. These enormous 

 changes of level are facts well recognised by geologists ; but the 

 point is — Do any of the writers whose views are cited claim these 

 earth movements to have taken place at the special geological period 

 required by Sir Henry's postulate, or do they even assert those 

 changes of level to have been either sudden or catastrophic. 



The authors quoted would, I believe, be the first to repudiate the 

 extraordinary inferences which Sir Henry seeks to draw from the 

 facts. For instance, I will take the paragraph in which Sir Henry 

 Howorth cites Prof. Spencer's remarks on the submerged valleys 

 of the Mississippi and the St. Lawrence. Prof. Spencer says, in 

 reference to the Mississippi : — " This valley is now submerged to a 

 depth of over 3000 feet, and is the representative of the channel of 

 the ancient Mississippi river, towards which it heads." 



This quotation, and others of like character, are brought forward 

 by Sir Henry as supporting his argument of a sudden and cata- 

 clysmic subsidence. Bearing this in mind, remark what Professor 

 Spencer says in relation to this same submergence, quoted from the 

 same paper as that from which Sir Henry has drawn his facts. 

 " The length of time required to excavate the channels of these 

 great rivers commenced as far back as the Palceozoic days. How- 

 ever, the culmination of that of the Mississippi was not until in the 

 later Tertiary, before the Pleistocene period. As the St. Lawrence, 

 now submerged to a depth of over 1200 feet for a distance of 800 

 miles, is mostly cut out of rocks of the Palaeozoic group, except 

 a belt of the Triassic, its antiquity must be very great. The 

 culmination was also probably in the later Tertiary era, like that of 

 the Mississippi, and the channels on the Californian coast, for there 

 are submerged Tertiary rocks off the coasts of Massachusetts and 

 Newfoundland at elevations much higher than the beds of the old 

 channels." Prof. Spencer, moreover, does not argue that these sub- 

 merged valleys or depressions in the Earth's surface are wholly due 

 to terrestrial crust movements, but that they one and all have been 

 made by the long-continued excavating power of rivers and streams. 



Such is the testimony of Prof. Spencer on these submerged 

 valleys or fjords, which is distinctly opposed to Sir Henry's inter- 



