190 Tertiary. 



the thickness of 10 feet, and the line clay 20 feet. The City of 

 Montreal is built upon this deposit. The bowlders are not confined to 

 the bowlder clay, but are also found in the sti'atified clays and sand. 

 Tiie bowlders derived from the mountain, have been drifted to the 

 southwest, in which direction they have been traced to the south 

 shore of Lake Ontario, 270 miles distant. The terraces are best seen 

 on the northeast side of the mountain. The rocks beueath the bowl- 

 der clay, are striated here S. 70° W, and S. 50° W. In some places the 

 surface of the bowlder clay has been deeplj^ cut into furrows by the 

 currents which deposited sand and gravel upon it. In like manner 

 the surface of the stratified clay, is sometimes cut into trenches filled 

 b}' the overlying sand. 



All the beds above referred to belong to the close of the Tertiary 

 period, and they are all marine ; but they may have been deposited at 

 distant intervals of time, and in waters of very various depths and area. 

 From the abundance of the Saxicava rugosa in the upper bed, it was 

 named the Saxicava sand, and from the abundance of the Leda port- 

 landica, in the middle bed, it was called the Leda clay. 



Dr. Albert C. Koch* stated that he collected, in 1839, in Gasconade 

 county, Missouri, about 400 3^ards from the bank of Bourbense river, 

 where there was a spring, the remains of a Mastodon under such cir- 

 cumstances as to show that it had been burnt to death, and while under- 

 going this punishment had also been struck with bowlders and shot 

 with arrows. The animal had evidently been mired as its legs were in 

 an upright position with the toes preserved. The ashes was from 2 to 

 6 inches in thickness, showing that the fire had been kept up for a con- 

 siderable length of time. In the ashes he found stone arrow heads, a 

 stone spear head, and some stone axes. The whole was covered by 

 strata of alluvial deposits consisting of clay, sand and soil from 8 to 9 

 feet thick. He also stated that about one year later he found another 

 Mastodon which he called the " Missourium," in Benton county, under 

 about 20 feet of alluvial deposits, and with the bones were several stone 

 arrow heads, one of which lay underneath the thigh bone, and in con- 

 tact with it. 



* Trans. St. Louis. Acad. Sei., vol. i. 



