156 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



JRev. Mr. Ilunting then called tlie attention of the meeting to 

 some fragments of mound pottery which he had recentlv ob- 

 tained in Wisconsin, and presented to the Academy. He also 

 presented some specimens of copper ore and other minerals 

 from Wisconsin, and described the position and circumstances 

 in which they were found. 



The following paper was then read : 



The Shell-Beds of the Vicinity of Davenport. 



BY W. H. PRATT. 



The deposits of shells in the soil along the banks of the river in this 

 vicinity have always attracted attention and excited some interest, and 

 seemed to challenge a more thorough and careful examination than has 

 hitherto been given them. 



Two different opinions have prevailed to some extent regarding the 

 origin of these formations. Some have been inclined to consider them 

 wholly, or principally, an artificial accumulation, formed — like the 

 " kitchen-middens" of Denmark and other parts of Europe, and some 

 probably in the United States— of the refuse of the repasts of our prede- 

 cessors in the occupancy of this country ; while others have attributed 

 them to the action of the river itself. As these beds are of considerable 

 extent in the aggregate, being found at the head of Eock Island, and 

 near the lower end of Credit Island, and on this side of the river at 

 East Davenport and at Gilbert, and also on the Illinois side, both above 

 and below Moline, and as they are of very uniform character, it may be 

 best to give first a general description, and then to note the particulars 

 more in detail. 



In the first place, then, the layers are usually in a horizontal position, 

 and varying from three or four centimeters to one meter in thickness, 

 pretty evenly distributed for some distance. Xo abrupt slopes or curves 

 are observed, and the layers never terminate or clmnge very abruptly, 

 but thin out rather gradually in each direction, though the very thin 

 layers, or lines, of shells are sometimes of but small extent. Where the 

 accumulation of shells is very heavy, they are packed quite closely to- 

 gether, and the interstices are rilled with the usual soil of the particular 

 locality, and the layer is usually covered with from three or four to thirty 

 centimeters of earth. One layer is not found above another, except in 

 cases where they are very thin, and close together, i. e., where layers of 

 earth are inters tratified. Sometimes the shells are so few and scattered 

 as not to form a continuous layer at all. 



The shell bed is usually found at, or very slightly above, high-water 

 mark, though, of course, it is upon rare occasions only that the water 

 attains that height, the highest flood during the year being usually con- 

 siderably less. The shell layer is ordinarily raised slightly above or built 

 upon the general surface of the plateau, and extends but a little way 



