Report on the Excavation of Mastodon Remains. 9 



side of the excavation, next to the bottom, showing that a pelvis 

 lies buried there. 



7. Two rib fragments, being the ends of two ribs, each ll 

 inches in circumference. 



8. A vertebra, presumably of the tail if derived from a masto- 

 don, as it is small, its centrum measuring only 3 inches in 

 length. 



EXTENT AND VALUE OF THE DEPOSIT. 



Before forming an opinion as to the probable extent of this 

 deposit of fossils, we should study the geological history of the 

 locality. The superficial stratum of the pond is a black waxy 

 earth, rich in organic matter. At the point where the fossils 

 were found, this layer has a thickness of about 7 feet. Under- 

 lying it is a stratum of grayish clay, two feet thick, in which the 

 fossils are imbedded. Then comes a layer of gravel, several 

 inches deep, containing specimens of Exogyra arietina. This, 

 in turn, is followed by a light-colored clay. 



The facts observed, together with the reasonable supposition 

 that the climate of this region was formerly more humid, lead 

 me to think that this depression was at one time much deeper, 

 and was then occupied by a small lake or marsh, and that it has 

 been slowly filled with wash deposits from the higher ground 

 surrounding it and with the products of animal and vegetable 

 decay. When mastodons frequented the region, they were 

 probably attracted to this spot by the presence of water or food, 

 occasionally perishing by becoming mired, or otherwise. Their 

 bones sank into the mud at the bottom; and as the lake was 

 slowly filled, the remains became more and more deeply im- 

 bedded, until now they rest eight feet below the surface. The 

 dense, damp clay, effectually excluding the air, has for these 

 thousands of years kept the remains in a fair state of preserva- 

 tion. The ordinary bony material of the specimens has not 

 deteriorated since these were exhumed, while the cement and 

 dentine show a tendency to crack and crumble, necessitating 

 repair. 



A question of great interest, and one often asked, is, How 

 long since these huge beasts inhabited the earth? To this ques- 

 tion geologists can give no definite answer in terms of years. 

 They tell us, however, that the fossils of the mastodon in Amer- 



