MAK AND THE GLACIAL PERIOD. 673 



Toward midday of July 13, 1887, while lying upon the 

 edge of the railroad cut, sketching the bowlder line, my eye 

 chanced to notice a piece of steel-gray substance strongly re- 

 lieved in the sunlight against the red-colored gravel just above 

 where it joined the lower grayish-red portion. It seemed to 

 me like argillite, and, being firmly imbedded in the gravel, was 

 decidedly interesting. Descending the steep bank as rapidly 

 as possible, the specimen was secured, . . . Upon examining 

 my specimen, I found that it was unquestionably a chipped 

 implement. There is no doubt about its being firmly imbed- 

 ded in the gravel, for the delay I made in extricating it with 

 my pocket-knife nearly caused me the unpleasant position of 

 being covered by several tons of gravel. . . . Having duly 

 reported my find to Professor Putnam, I began at his request a 

 thorough examination of the locality, and on May 25, 1888, 

 the year following, discovered another implement, four feet 

 below the surface, at a place about one eighth of a mile from 

 the first discovery. . . . The geological formation at which 

 the implement was found seems to be a reddish gravel mixed 

 with schist. 



The implements thus discovered by Mr. Cresson in this 

 early deposit of the Glacial period must be connected with 

 others near by, found by him several years before in a shel- 

 ter-cave, since destroyed by the railroad excavation. This 

 was situated near the small building that appears at the right 

 of our picture.* Interested as a youth in the reports of 

 cave explorations in Europe, he carefully excavated this rock 

 shelter in 1866, making notes of and preserving everything 

 he found. As recorded at the time, the lower part of this 

 cave was filled to a depth of about six feet with a deposit ap- 

 parently identical with the Philadelphia red gravel and brick- 

 clay. This contained only palaeolithic implements of argil- 

 lite similar to those (figured on the following page) from the 

 railroad cut near by. Argillite implements, mingled with 

 others of jasper, quartzite, and bone, with fragments of pot- 



* Soe Fig. 183, p. 670; also "Proceedings of the Boston Society of Natural 

 History," vol. xxiv, p. 145. 



