70 MEETING, MONDAY, APRIL 4. 



contains boulders of large size from up the river, and is 

 found for a long distance at a height of one hundred and 

 fifty feet. These facts were discovered by Prof. H. C. 

 Lewis, of Philadelphia, by whose courtesy I am allowed 

 to present them and with whom I have been permitted to 

 spend two weeks in reviewing the field. The conclu- 

 sion is that the gravels containing flint implements at 

 Trenton mark the closing stages of the glacial period, 

 when water was excessively abundant from the melting 

 of the ice, and pebbles for transportation were at hand in 

 the freshly deposited kames and moraines of the glacial 

 region above. The evidence is conclusive that man was 

 in New Jersey before the glacial period. How much 

 before we have no means of determining. 



The remaining question is, When did the ice of the 

 the glacial period disappear? 



Evidence accumulates that this period is more recent 

 than has been currently supposed. In the Am. Jour, of 

 Science for Feb., 1881, I published a paper in which an 

 attempt was made to estimate the age of a kettle hole in 

 Andover, similar to the dungeons in Marblehead. This 

 kettle is three hundred feet across at the top, and about 

 sixty feet deep. The bottom is tilled with a peat bog 

 ninety feet in diameter. It is scarcely possible for it 

 originally to have been more than twenty-five feet deeper 

 than it is at present. This would represent a deposit 

 upon the present surface of the peat of only eight feet. 

 If the kettle was formed at the close of the glacial period 

 it would hardly be reasonable to place that epoch back 

 80,000 or 100,000 years as is now customary upon astro- 

 nomical grounds. For if we suppose the kettle hole to 

 have existed 80,000 years we are compelled to believe 

 that 1,000 years would be required for an inch of solid 

 matter to accumulate upon the present surface of the peat, 



