FRONTAL TERRACES. 25 



Succeeding the kame area on the west of Hamilton is an interesting 

 development of terrace at two levels. The kames grade into the higher 

 one, which is a mile in length and three-fourths of a mile wide, reaching 

 around by a single lobe toward the Eaton valley. The altitude is 50 

 feet, the top very smooth, and the eastern border kame-like. There are 

 no fresh sections by which the structure can be determined. Midway the 

 terrace is interrupted by a transverse non-erosion channel from north- 

 west to southeast. A cross-section of the shallower portion toward the 

 hillside shows a top width of 12 rods, bottom width of 6 rods, depth of 

 18 feet, and side slopes of 15 degrees. At the eastern margin it is slightly 

 wider, the slopes steeper, but smooth as before, and cuts the terrace to 

 its base. It extends across the terrace by a rather smooth curve. The 

 presence of stagnant ice is a possible, but forced, explanation. It may 

 be that after building the apron south of the channel the glacier re- 

 treated and made another frontal discharge, whose southern border was 

 near and parallel to the northern face of the earlier one. Such prox- 

 imity and parallelism would be surprising, but the northern concavity 

 of the axial curve and the slightly lobate character of the slopes on the 

 north side at least suggest it as a possible mode of origin. 



The lower terrace drops 15 feet where it abuts upon the higher, or 

 where, as should perhaps be said, the higher one is built out upon it. It 

 stretches southward three-fourths of a mile, roughly triangular, project- 

 ing upon the broad floor made by the coalescence of the two valleys, but 

 extending around to the west and north, the two terraces together form- 

 ing a rude V at the south end of the inter-valley ridge which rises north- 

 ward. The marginal slopes are constructional forms with gentle kame 

 contours on the east, becoming somewhat lobate south and west. The 

 surface is not pitted, the marginal slopes run from 12 to 18 degrees, and 

 the height at the border is from 20 to 25 feet. A slight bench appears 

 on the east side of the valley below Hamilton, at the higher level ; also 

 farther up and across Eaton valley, but in the latter case not at strictly 

 accordant levels. The conditions here suggest comparison with those 

 described by Russell, where mountain spurs project into the Malaspina 

 glacier, producing melting and lake waters on either hand.* Similar 

 terraces might be expected about the point north of Pecksport or at Che- 

 nango Forks, but do not occur. 



Frontal terraces occur in a limited way above Hamilton in association 

 with the Reservoir kames, and in a more extended manner reaching off 

 from the kame area at Chenango Forks. The latter have not been suf- 

 ficiently studied for careful description, but mention should be made of 



♦Second Expedition to Mount Saint Elias. I. C. Russell ; 13th Ann. Rep. U. S. Geological Sur- 

 vey, p. 77. 



IV— Bull. Geol. Soc. Am., Vol. 8, 1896 



