July 21, 19 10] 



NATURE 



77 



graphical ^ludy of the subject is made paramount; in 

 the second, petrology, mineralogy and mining receive 

 the fullest treatment. 



(i) Of especial interest is the professional paper 

 first on uur list, containing the results of Prof. Tarr's 

 recent investigation of the great glaciers in the 

 VaUutnt Bay region of Alaska. We may congratulate 

 ourselves, and Prof. Tarr also, on the happy mis- 

 chance which took him to this region at a critical 

 time in the history of its ice-fields. 



Ever since the famous explorations of the late Prof. 

 I. C. Russell, twenty years ago, we have known that 

 where tlie i^reatest of these ice-rivers left the moun- 

 tain valleys and deployed as "piedmont" glaciers on 

 the low ground bordering the ocean, they were charac- 

 terised by their peculiarly stagnant condition. The 

 anomaly of dense livint;' forests covering their sur- 



moraine was sliding out of sight into the yawning 

 chasms — the green forests that covered it were shar- 

 ing the same fate — the snouts of the glaciers were 

 being thrust forward destructively into the timbered 

 belt surrounding them — the enormously augmented 

 streams issuing from the ice were impassable, and 

 were flinging out huge delta-fans that buried every- 

 thing in their path ; and, altogether, nature in one of 

 her most vigorous moods was enacting a grand trans- 

 formation scene on the lonely shores of Yakutat Bay. 

 i\ll the eastern portion of the great Malaspina Glacier 

 was a maze of crevasses, and its end — formerly an 

 easv slope — an insurmountable cliff of tumbling ice, 

 trees, and moraine. The Atrevida (see Fig. i), the 

 Variegated, the Marvine and the Haenke Glaciers 

 were in the same state of rapid disruption ; while 

 others, including the Lucia and the Seward, though 



\ ,.;u 1 tin,- uest from Hidden GL-icier showing the Fosse and the Pitted Pla 



faces «\'er large areas where the ice was hidden be- 

 neath a thick blanket of moraine was one of the 

 many surprises brought to our knowledge by Russell ; 

 and later investigations confirmed the idea that in 

 such cases the ice was truly "dead" and would re- 

 main where it was, a waning relic of severer bygone 

 times, until graduallv dispersed by liquefaction. 



Such was still the state of affairs when Prof. Tarr 

 began his survey-work in the region in the summer 

 of 1905, and he confidently planned a programme for 

 the following year which depended for its fulfilment 

 on the "deadness " of the ice. On his return in 1906 

 he was naturallv astonished to find that all was in a 

 turmoil of change — familiar features obliterated — 

 routes impossible. The "dead ice" in many places 

 had sprung to life again — the plains that had formed 

 the highways of former travel were broken into an 

 impenetrable wilderness of crevasses — the blanket of 



NO. 2125, VOL. 84] 



not so fully aroused, showed symptoms of impending 

 change.' 



Vet there were other glaciers in the region that had 

 not participated in this energetic outburst, but still kept 

 to the habit of recession which had been regarded as 

 the normal behaviour of all these .Alaskan glaciers. 



Here, then, was the unexpected problem that con- 

 fronted Prof. Tarr in 1906 and richly recompensed 

 him for the destruction of his original plans. His 

 solution of it is remarkably simple, and seems to fulfil 

 all the conditions. It is' well known that in 1899 

 the region was affected by a sharp earthquake, which 

 caused displacements recognisable on the coast-line 



1 In the NationnlGeografhic Mas;a-jKi for Janu.iry Ian Prof. Tarr and 

 Prof. L. Martin give an account of their later visit to the region in the 

 summer of igog, when further chanzes were noted. The Lucia Glacier had 

 become unpassable ; the Hidden Glacier had undergone the full cycle of 

 changa ; the Hubbard seemed to be on the eve of great movement', while 

 the four mentioned above as active in 1906 had relapsed into stagnation. 



