Swiss Geography. 179 



September 16, and went on at once to Alpnacht, 

 at the extreme end of the south-western arm of 

 the lake, having on my left the starting-point of 

 our former walk. I did not expect to see any- 

 thing of autumn migration quite so early as this, 

 or I should have taken the St. Gotthard line 

 direct to the great tunnel, and then have estab- 

 lished myself at once at or near the head of the 

 Reuss valley which the railway follows ; but I 

 wished to see what birds were still to be found 

 in the lower levels, and determined to spend a 

 day or two in the great valley of Hasli, where I 

 left my. reader at the end of my third chapter. 

 Before I take him further on this second round of 

 exploration, I must ask him to look with me at a 

 map of Switzerland, in order that we may under- 

 stand the geographical conditions of the problem 

 about which I was now going to try and learn 

 a little. 



A little study of a good map will show that the 

 true alpine region of Switzerland proper consists 

 of two enormous mountain barriers, fencing in, to 

 north and south, a deep trench, nearly a hundred 



miles in length. This trench represents the 



N 2 



