276 Field and Forest Rambles. 



valley, runs straight across another ; and when thaws take 

 place, there would be a jamming and banking back of the 

 waters, which would indicate levels of subsidence much like 

 the terrace cliffs. 3rd. That the terraces indicate fitful oscil- 

 lations of level is also a feasible hypothesis. Referring to the 

 banking-back supposition ; I before alluded to the fact that 

 there are now and then jams of ice on the great rivers of a 

 serious character, so as to inundate large tracts in the valleys, 

 and add to the deposits. An instance of this description is 

 shown on page 277. It occurred during a sudden freshet of 

 1 83 1, when the ice broke up suddenly on the St. John. The 

 result was an enormous piling up of huge icebergs at a portion 

 of the river called " The Narrows," about two miles below 

 Fredericton, causing the river to overflow its banks and 

 inundate the flat on which the capital is built. 



So sudden and simultaneous was the breaking up through- 

 out the river's course on the above occasion, that vast islands 

 of ice got stranded, or set on end like polar bergs, and rose 

 even to the level of the housetops, so as to threaten the 

 complete destruction of the city as they passed onwards, 

 scraping and tearing up the banks, and carrying destruction 

 to everything that opposed their irresistible movements. 



Now we might easily believe that similar phenomena (of 

 course on a very much grander scale), at the close of the 

 Glacial epoch, would be equal towards the formation of the 

 heaps of valley gravels observed throughout the river courses 

 and drainage hollows; moreover, without perhaps doing any 

 violence to facts, we might on this supposition explain the 

 great mounds and ridges of sorted detritus seen in various 

 situations. I conceive, therefore, if a higher elevation of the 

 country is allowed, and the land-ice theory enter^tfmed, that, 

 as far at least as the fluviatile, or rather stratified gravel and 

 clay deposits of the inland valleys are concerned, there is an 

 apparent solution of the difficulty in these modern examples. 



