xl 



May he had observed in forty-five years, and that thus far every 

 month of the year has given us less rain than the average. 



October 6, 1879. 



A. Todd in the chair. Ten members present. 



The Corresponding Secretary presented in behalf of Mrs. Ab- 

 ner Foster, of Beardstown, Ills., a box of mound builders' crania, 

 with a collection of flints ; accompanying which was a paper 

 entitled, " A Description of Mounds and Prehistoric Relics of 

 Cass, Schuyler and Brown Counties, Illinois." 



On motion of Judge Holmes, this paper was referred to the 

 Publication Committee. 



He also presented a photograph of footprints on the triassic 

 rocks near Booneville, N. J., a donation of Mr. Israel C. Russel. 



In behalf of James H. Brookmire, Dr. Forbes presented four 

 specimens of spider-crabs, from Biddeford Pool, Maine. 



October 20, 1879. 

 Dr. Engelmann in the chair. Nine members present. 

 The Corresponding Secretary read the following communica- 

 tion from Capt. Chas. M. Scott on 



THE FORMATION OF THE BANKS OF THE LOWER MISSISSIPPI. 



The banks of the Mississippi below the junction of the Ohio present 

 phenomena that have often led to erroneous opinions. The banks are 

 sometimes at different heights at places in close proximity to each other. 

 At one place, the river overflows the banks, during high water, from one 

 to three feet, and again, in less than a mile, banks are found that extend 

 above the highest wa;ter known, from one to three feet, and occasionally 

 even more. These high banks have been taken as a proof of an earlier 

 formation. 



I do not claim to be a scientist in any way; yet, having been an ob- 

 server of the phenomena of the Mississippi, I will presume to give you the 

 observations I have made in the hope that facts will lead to a better under- 

 standing of the laws that govern our river. The first thing that strikes an 

 observer is the instability of the banks. The second is the luxuriant vege- 

 tation ; and if the observer passes during low water he will not fail to 

 notice the size and frequency of the sandbars. The banks are composed 

 of alluvium with a large proportion of sand. This mixture is not of uni- 

 form texture, but has a greater proportion of sand as the deposit that 

 forms the present banks has taken place on the outer side or on top of a 

 bar, or under or behind a bar, or haply in an old cut-off. Should it be on 



