Hir.TT-LKVRL OKAVKL IN NEW EXCLAXD. 401 



not accept tlic jjlacial-ilam hypothesis. Now I am able to give ueoniorpliic data in 

 supiwrt of my position in setting; aside the necessity of <;lacial (hims. 1 have fonnd 

 on the western, southern and eastern sides of the New Kngland mountain masses 

 tlie same terraces as those on the northern, without other variation than sucli as 

 arose from the c]uin*j;in<2: to})ography. The terraces of the great valleys are not those 

 of rivers, but approach the levels of i)lains, and in the descent from the higher to 

 the lower country they do not slope outward and down the valleys as river terraces, 

 but descend abruptly as steps, from a few to 200 feet or more in height, of tiie same 

 character on all sides of the mountains. The terrace i)lains at substantially the same 

 levels extend down the valleys for miles before terminating in the abrupt steps. The 

 materials came primarily from the drift, but that of the lower terraces canie chiefly 

 from the erosion of those above. The materials thin out as the valleys become 

 larger and broader and farther from the sources of supply ; and, furthermore, as 

 the rivers keep cutting deeper and deeper and leaving the terraces higher above 

 them the erosion is so increased that the terrace materials do not connnonly extend 

 from one great valley to another. I conclude that the terrace plains were formed 

 at sealevel, and that the mountain region has been raised as much as the sum of 

 the heights of the terrace steps, or more than 2,000 feet since tjie (ilacial i)eriod, 

 but that the co;ustid region need not have been depressed to the maxinunn depth, 

 for it luus been observed in the southern mountains and in the West Indies tiiat 

 during the last epeirogenic movements the mountain regions have Ijeen raised to a 

 greater extent than tiie coast;d plains. 



A proi)ositi()n to relieve the very extensive program of the meeting 

 hy the creation of a temporary petrogra])liic section where the several 

 technical papers in petrology and mineralogy should he read was voted. 

 The j>roceedings of that section will be found on page 409. 



The next pai)er in the main section was — 



I 'A RIA TI O NS OF G LAC IE RS 

 15 Y 11. F. HEin 



lAbstmcQ 



Great interest has been aroused lately in the study of the variations of glaciers. 

 Observations on theglaciei*s of the Alps have shown that variations in their dimen- 

 sions undergo a ])eriodic change; that they increase, attain a maximum, decrease, 

 reach a mininumi, and then begin to advance again two or three times in a cen- 

 tury. Records of more or less exactness exteml back two or three hundred years. 

 Glaciers, however, are not all in the same jjliase at the same time; indeed, some 

 l>egin to advance when others have almost reached their maxinunn. (ilaciei's side 

 by siile are son>etimas found in opposite phases. This makes it so dillicult to find 

 the relation l>etween the variations of climate and of glaciers. Some progress has, 

 liowcver, l)cen made in this direction. The theories of Kichter and (»f Forel, ad- 

 vanccfl to a<Tount for the curious behavior of glaciers, were explainecl. Accurate 

 infonnati(»n is wante<l on the <-hanges which glaci«'rs undergo. The International 

 (Vingrt'SH of ( M'ologists at Zurich last sinnmer ajipointetl a conuiiittee to collect in- 

 formation on the variations in L'laci(!rs all over the worM. '{'he rest of the paper 



