ments have been reported to Professor Haynes from the glacial gravel from the Lehigh Valley, near Bethlehem, Pa. Miss Babbitt reported to the American Association for the Advancement of Science, last year, the

PLATE III. (Taken from 'Studies in Science and Religion') shows, in addition to the glaciated area of New Jersey, the glacial terraces of gravel along the Lehigh and Delaware rivers, and also the "Delta Terrace" at Trenton, fifty feet above the river, in which Dr. C. C. Abbott has found paleolithic implements.

discovery of similar implements at Little Falls, Morrison County, Minn., and the gravel terrace in which they are found is pronounced by Mr. Warren Upham, one of the best authorities on the subject, to belong to

the modified drifts deposited at the close of the glacial epoch. ('Proceedings of the American Association for the Advancement of Science,' vol. xxxii, pp. 385-390.) And Mr. F. S. Reefy, of Elyria, has recently

PENNSYLVANIA

NEW JERSEY

PLATE IV.-The broad, black line shows Southern Boundary of Glaciated Area of Pennsylvania.

received from Tuscarawas County, from the valley of Sugar Creek, some rough implements, which, so far as form is concerned, may well belong to the paleolithic age. The important question, however, concerning

these and all similar implements, is: Do they really belong to the stratified gravel which is so abundant in the valley of Sugar Creek, just below the glacial limit? There is no question that the gravel deposits in the upper portion of the Tuscarawas River and its tributaries belong to the same age with those in the Delaware River at Trenton. But there are so many ways in which an inexperienced observer is liable to be

PLATE V.-Map showing Southern Boundary of Glaciated Area of Southern Ohio.

deceived with respect to the original position of an implement that great care should be taken whenever one is found to observe all the circumstances, and to describe them with as full detail as possible. An implement, for example, may occur some distance below the surface of a gravel deposit without having been in that position originally; it may have been buried in a grave or pit; it may have fallen down, or have been washed

down, from the top of a bluff or knoll, and subsequently buried by other débris which was washed down, or which crept down, in the same way. It is important, therefore, that experienced observers should be called to note the situation as soon as possible after an implement is found; or better still, that local observers in the vicinity of the margin of the glaciated area should make a careful study of the glacial deposits in the river valleys, so as to be able themselves to detect and report all the important elements of the problem.

The search for palæolithic implements is likely for some time to be discouraging. For they are so rude in their character as not to strike the eye so readily as the more polished instruments of a later day; and, even in the most favored localities, the palæoliths are so few in comparison with the amount of gravel in which they are deposited that it is somewhat like looking for a needle in a haymow, and only the most practiced eye stands much of a chance to be rewarded by a discovery. Professor Lewis and myself, for example, have never been able to find a palæolithic implement, even in Trenton, though we have searched long and diligently for them. The secret of our failure doubtless arose from the fact that our attention had been so constantly directed to observing scratched stones and other glacial phenomena that we could not concentrate it upon anything else when looking upon a mass of gravel. But Professors Dawkins and Haynes, and even Dr. Abbott's twelve-year-old son, would find them in our tracks five minutes after we had walked over them, discovering as many as a half dozen in a walk of two or three hours. The secret of Dr. Abbott's success in discovering palæoliths at Trenton lies, however, not only in the fact that he has the trained eye of a careful observer, but that extensive excavations are continually in progress in the gravel deposits near where he lives. At one place near his house the river is extensively undermining the gravel bank and exposing fresh sections of the bluff; at other places pits have been dug to get at clay deposits, and at many others the railroads are removing the gravel for ballast. By taking advantage of these operations, he is able to make frequent observations under the most favorable circumstances. It is greatly to be desired that other observers similarly situated should be on the lookout for these earliest and most interesting remains of ancient man.

Another class of facts to which attention should be directed pertains to the determination of the date of the close of the glacial period. The means of attacking this important problem exist all over the glaciated