172 SCTEXCE IX bilOJiT CHAFTEKS. 



at the mouth of an estuary, or of a valley whose river had 

 already deposited its suspended matter (a common case here- 

 abouts, where so many rivers terminate in long estuaries or 

 open out into bag-shaped lakes near the coast), and where the 

 bottom had not been modified by secondary glaciation, that the 

 receding tide displayed a sea-bottom of till, covered with a thin 

 stratum of loose stones and shells. In some cases the till was 

 so bare that it appeared like a stiff mud deposited but yesterday. 



At Bodo, an Arctic coast station on the north side of the 

 mouth of the Salten fiord (lat. 67 20'), where the packets 

 make a long halt, is a very characteristic example of this : a 

 deposit of very tough till forming an extensive plain just on 

 the sea-level. The tide rises over this, and the waves break 

 upon it, forming a sort of beach by washing away some of the 

 finer material, and leaving the stones behind. The ground be- 

 ing so nearly level, the reach of the tide is very great, and thus 

 a large area is exposed at low tide. Continuous with this, and 

 beyond the limit of high tide, is an extensive inland plain cov- 

 ered with coarse grass and weeds growing directly upon the 

 surface of the original flat pavement of till. 



There is no river at Bodo ; the sea is clear, leaves no appre- 

 ciable deposit, and the degree of denudation of the clayey 

 matrix of the till is very much smaller than might be expected. 

 The limit of high water is plainly shown by a beach of shells 

 and stones, but at low tide the ground over which the sea has 

 receded is a bare and scarcely modified surface of till. I have 

 observed the same at low water at many other Arctic stations. 

 In the Tromso Sund there are shallows at some distance from 

 the shore which are just covered with water at low tide. I 

 landed and wade4 on these, and found the bottom to consist of 

 till covered with a thin layer of shells, odd fragments of 

 earthenware, and other rubbish thrown overboard from vessels. 

 It is evident that breakers of considerable magnitude are neces- 

 sary for the loosening of this tough compact deposit that it is 

 very slightly, if at all, affected by the mere flow of running 

 water. 



I specify these instances as characteristic and easy of verifi- 

 cation, as the packets all stop at these stations ; but a yachts- 

 man sailing at leisure amid the glorious coast scenery of the 

 Arctic Ocean might multiply such observations a hundredfold 

 by stopping wherever such strands are indicated in passing. I 

 saw a multitude of these in places where I was unable to go 

 ashore and examine them. 



