Gregory — Progress in Interpretation of Land Forms. 121 



The first detailed description and unequivocal inter- 

 pretation of either terminal or recessional moraines is 

 from the pen of Gilbert (1871), 58 geologist of the Ohio 

 Survey. In discussing the former outlet of Lake Erie 

 through the Fort Wayne channel, Gilbert writes : 



" The page of history recorded in these phenomena is by no 

 means ambiguous. The ridges, or, more properly, the ridge 

 which determines the courses of the St. Joseph and St. Marys 

 rivers is a buried terminal moraine of the glacier that moved 

 southwestward through the Maumee valley. The overlying Erie 

 Clay covers it from sight, but it is shadowed forth on the surface 

 of that deposit, as the ground is pictured through a deep and 

 even canopy of snow. Its irregularly curved outline accords 

 intimately with the configuration of the valley, and with the 

 direction of the ice markings; its concavity is turned toward 

 the source of motion; its greatest convexity is along the line of 

 least resistance. 



South of the St. Marys river are other and numerous moraines 

 accompanied by glacial stria?. Their character and courses 

 have not yet been studied; but their presence carries the mind 

 back to an epoch of the cold period, when the margin of the ice- 

 field was farther south, and the glacier of the Maumee valley was 

 merged in the general mass. As the mantle of ice grew shorter — 

 and, in fact, at every stage of its existence — its margin must have 

 been variously notched and lobed in conformity with the contour 

 of the country, the higher lands being first laid bare by the 

 encroaching secular summer. Early in the history of this 

 encroachment the glacier of the Maumee valley constituted one of 

 these lobes, and has recorded its form in the two moraines that 

 I have described. ' ' 



Three years after the recognition of moraines in the 

 Maumee valley, Chamberlin (1874) 59 showed that the 

 seemingly disorganized mounds and basins and ridges 

 known as the Kettle range of Wisconsin is the terminal 

 moraine of the Green Bay glacier. At an earlier date 

 (1864) Whittlesey interpreted the kettles of the Wis- 

 consin moraine as evidence of ice blocks from a melting 

 glacier and presented a map showing the "southern 

 limit of boulders and coarse drift." In 1876 attention 

 was called to the terminal moraine of New England by G. 

 Frederick Wright, who assigns the honor of discovery to 

 Clarence King. 



With the observations of Gilbert, Chamberlin, and 

 King in mind, the terminal moraine was traced by 

 various workers across the United States and into 



