MAN AND THE LAVA BEDS. 707 



is so passionately in love would seem to resemble closely 

 those which evidently surrounded palaeolithic man in New 

 Jersey, Ohio, Indiana, and Minnesota. But, on the other 

 hand, such human remains as we have from the Trenton 

 gravel are regarded by Professor Putnam as belonging to a 

 race distinct in type from the Eskimo. 



A closing remark is in place with reference to the date 

 of man's appearance in America. In the first place it should 

 be observed that, to say man was here before the close of 

 the Glacial period only fixes a minimum point as to his an- 

 tiquity. How long he may have been here previous to that 

 time must be determined by other considerations. Secondly, 

 with our present knowledge of glacial phenomena, the date 

 of the close of the Glacial period is regarded as much more 

 modern than it was a few years ago. Sir Charles Lyell's 

 estimate of thirty-five thousand years as the age of the Niag- 

 ara gorge, which is one of the best measures of post-glacial 

 time which has yet been studied, is greatly reduced by what 

 we now know of the rate at which erosion is proceeding at 

 the falls. Ten thousand years is now regarded as a liberal 

 allowance for the age of that gorge. But, finally, the term 

 " close of the Glacial period " is itself a very indefinite ex- 

 pression. The Glacial period was a great while in closing. 

 The erosion of the Niagara gorge began at a time long sub- 

 sequent to the deposit of the gravel at Trenton and at Madi- 

 sonville. Between those two events time enough must have 

 elapsed for the ice-front to have receded a hundred miles or 

 more, or all the distance from New York to Albany ; since 

 only at that stage of retreat would the valley of the Mohawk 

 have been freed from ice so as to allow the Niagara River to 

 begin its work. The deposits at Trenton, Madisonville, and 

 Medora, took place while the ice-sheet still lingered in the 

 southern water-shed of New York and Ohio. When, there- 

 fore, the age of the mound-builders of Ohio is reckoned by 

 centuries, that of the glacial man who chipped these palaeo- 

 lithic implements must be reckoned by thousands of years. 



As is evident from the description of Mr. Upham, the 



