Correspondence — Mr. Marshall Sail. 475 



TEERACES OF NORWAY. 



SiK, — I much regret that Col. Greenwood hit upon the wrong 

 Aardal. That which I referred to is at the east end of the Sogne 

 Fjord. Steamers make the trip, and, once a fortnight, also call at 

 Fjeerland, within an hour's stroll of a glacier remanie, the Suphelle 

 Bree, which descends to certainly not more than 150 feet above the 

 sea level. A valley to the north contams capital terrace examples, 

 and is closed by the great glacier of Boium's Brae. From Bergen to 

 the Sogne Fjord, to Fjserland, and to Aardal, the Mork Foss, back to 

 Grudvangen, across to the Hardanger Fjord, up the Sor Fjord to 

 Odde, thence a-cross the FolgeFond by an easy glacier pass to Bondhus, 

 and westward to Stavanger, would be a fortnight's deliberate trip, 

 and afford sublime scenery, with geology enough for a glutton, be- 

 sides numerous lateral excursions, should the traveller have time. 

 He must study the times of the steamers well in laying his plans. 



I am sorry Col. Grreenwood did not accept my invitation to intend- 

 ing explorers to ask me any questions. Marshall Hall. 

 Yacht Norna, Sept. 19, 1871. 



RIVER TERRACES. 



Sir, — In the two letters on this subject which you have done me 

 the honour to publish in your numbers for April and September, I 

 have contended that inland river terraces are very simple effects of 

 rain on rivers ; that they are the remains of alluviums formed on 

 land by the overflow of rivers ; and in the report of Mr. Chief Justice 

 Begbie's account of the "Benches of British Columbia" in the 

 Proceedings of the Royal Geographical Society for July, the Chief 

 Justice remarks (page 138) that the rise of the Fraser river in flood 

 at Lilloet is 40 feet ; at Fort Alexandria 25 feet. Here, then, must 

 be two alluviums forming on land at the present day below the old 

 terraces. Gorges, by checking the rain-floods of the river, cause 

 these enormous rises. When, however, the beds of these gorges 

 are deepened by erosion, the river, unable to overflow the alluvial 

 banks which it has built up, will, in floods, tear them down and will 

 drive them to the hill-side as two parallel terraces. 



The prevalent opinion, however, in the discussion of the paper was 

 that the terraces have been formed at the water level of lakes by 

 materials washed down by the river, and not on land alluviums. A 

 "bursting of the barrier " is then supposed, and "a sudden drain- 

 age " of the lake to the level of the succeeding terraces. And so a 

 succession of " bursting of barriers " and a succession of " sudden 

 drainages," one of each of these for each pair of terraces. Each 

 barrier which it is required to " hurst " being perhaps a gorge of 

 the hardest possible rock, and extending for any number of miles. 

 But to form two parallel terraces the river must have filled the lake 

 entirely with the materials carried down. In this case there could 

 be no " sudden drainage " of a lake which had no water in it. Or 

 are we to suppose that in former times all rivers on entering the lakes 

 bifurcated and deposited their materials as terraces at the level of 

 the water on the two opposite side-shores of the lakes, leaving the 



