Niles.] 324 [March 6, 



rows, which is also evident, but less marked, in E. Oslen-Sackenii. 

 Between these four rows other, but smaller, points are scattered. 



Plate 9, fig. 1, Eplbates Osten-Sackenii Burg. 1, a, head. 



Fig. 2, Glulops singularis Burg. Head in profile, and fig. 2, a, 

 head in front. Fig. 2, b, antennae; c, wing; d, tip of middle tarsus. 



General Meeting. March 6, 1878. 



The President, Mr. T. T. Bouve, in the chair. Twenty- 

 one persons present. 



Messrs. Harold C. Ernst and John A. Estabrooks were 

 elected Associate Members. 



The following paper was presented by title : — 



Upon the Occurrence of Zones of different Physical 

 Features upon the Slopes of Mountains. By Prof. W. 

 H. Niles. 



Daring the summer of 1876, I observed among the Alps that many 

 of the longer mountain slopes presented three different decliv- 

 ities, and that each of these divisions had its characteristic phys- 

 ical features. If from a moderate elevation and distance we ob- 

 serve the profile of an Alpine slope, which has these three divisions 

 well marked, we first notice the greater steepness of the upper and 

 lower portions as compared with the intermediate one. If we then 

 study the features in detail we find that the summit region, except- 

 ing the snow-fields, presents a much broken or serrated outline, that 

 the middle division exhibits a series of convex undulations like an 

 irregularly corrugated surface, and that the lowest section may be 

 either a single regular slope, or a series of slopes of different inclina- 

 tions. 



I have come to the conclusion that a similar distribution of physi- 

 cal features is a very common characteristic of mountain slopes, and 

 it is with the hope of leading to a more thorough knowledge of our 

 own hills and mountains, that I present these notes taken upon for- 

 eign ground. 



The mountains which best exhibit the divisions in question are 

 those which, like many of the Alps, rise directly from the level of 



