MUSSEL FAUNA OF THE KANKAKEE BASIN. 



39 



COMMERCIAL VALUE OF THE SHELLS OBTAINED. 



The relative values of the mussel shells from the Kankakee Basin 

 were determined by Mr. J. F. Boepple, lately deceased, a mussel 

 expert of wide experience and high authority, then stationed at 

 Fairport, Iowa. 



Average lots of the different species were weighed, blanks of vari- 

 ous diameters were stamped upon the inside of the shells and counted, 

 the number of similar blanks which could be obtained from a ton 

 of shells was computed, and from these data, together with the 

 quality of the pearl, the value per ton was calculated. In many 

 instances the results of these computations were verified by sending 

 the stamped shells to a button factory, where the blanks were 

 actually sawed out, and their value given. 



These values are expressed in the following table, each value quoted 

 being an average from several lots of the same species. The diameter 

 of the blanks is measured in "lines'' (=^V of an inch), IG, 18, etc. 

 " F." and " M." denote first and medium quality. " T." indicates that 

 more than half of the blanks are '' tips," that is, uneven in thickness 

 and of poor quality; " t." indicates that considerably less than half 

 are tips. The numerals " 1," " 2," and " 3 " indicate different grades 

 of shells, including size, color, luster, etc. Thus, reading the second 

 line, 1 ton of second quality L. Jigamentinus shells would yield 1,119 

 gross of 20-line blanks, more than half of which would be " tijjs." 

 The value of blanks and tips together would be $33.57. 

 . Table of Shell Values. 



