GEOLOGY. 321 



and Harlan of Philadelphia. The President said that, being in Balti- 

 more, he sought for this tooth, and ascertained it had disappeared somo 

 time before, in a manner wholly unknown. Some time after, being in 

 the Museum of the Academy of Natural Science, Philadelphia, looking 

 over a fine collection of Mastodon teeth, in company with Dr. Hays, 

 this gentleman discovered a tooth which had all the characters of the 

 lost Baltimore specimen. Dr. Wilson, who had given it to the Acad- 

 emy, on being inquired of, said that it was purchased by his brother 

 in London, as a supposed American fossil. On examination it appeared 

 to have none of the characters of the tooth of the American Mastodon 

 gigantcus, but evidently belonged to the narrow-toothed group, either 

 Angustidens, Longirostris or Humboldtius. Furthermore, whatever 

 was its species, it was a Miocene fossil, and, of course, was derived 

 from a deposit that had never presented any relic of M. giganteus, in 

 this country. Being an insulated fossil, since none belonging to the 

 same species or group had ever been seen among thousands of Masto- 

 don specimens met with in North America, it was of course an object 

 of great interest, and he had been led to investigate its history with 

 all possible exactness. All the evidence he could obtain concurred in 

 supporting the opinion that it was the tooth actually possessed by Dr. 

 Ducatel, and which was brought to light in the manner he had 

 described. On a recent visit to Europe, the President said he had 

 taken with him a cast of the tooth, colored, under the direction of 

 Dr. Wilson, exactly as when discovered, and exhibited it to Sir Charles 

 Lyell and Mr. Charlesworth, who were fortunately in London. Both 

 of these gentlemen distinctly recognized it as the tooth they had for- 

 merly seen in America. On exhibiting it to Professor Owen he 

 thought the fact of its being an insulated fossil ought not to be consid- 

 ered an objection to its being a native of America, since every newly 

 discovered species would be liable to the same difficulty. He consid- 

 ered it as decidedly belonging to the narrow-toothed group, and 

 thought it probable that other portions of a skeleton might hereafter 

 be found in the southern parts of the United States. The President 



which existed in regard to it, and either restore it to the Old World, or 

 establish it as a native inhabitant of the New 



FOSSILS FROM THE POSE-PLIOCENE 0? MASSACHUSETTS. 



MR. STIJIPSON has given to the Boston Society of Natural History a 

 list of fourteen different varieties of shells obtained from the post-plio- 

 cene deposits of Point Shirley, near Boston. These fossils occur in 

 the upper part of a stratum of blue clay and pebbles, which crops out 

 from under the coarse drift, at the cliffs on both sides of the hill. On 

 the east side the stratum is at an elevation of fifty or sixty feet above 

 high-water mark ; on the west side it is but two or three feet above 

 the same level. At some little distance from this site, a stratum of 

 clay, probably the same, containing shells, was met with in digging a 



