492 CHARLES A. DAVIS 



The finer material was also sorted by stirring, settling, and 

 decantation, and the matter of different degrees of fineness dried 

 and weighed. The finest matter was usually separated from the 

 water by filtering through a dried and weighed filter, and the 

 water concentrated by evaporation and again filtered to remove 

 any of the calcium carbonate dissolved in the various processes, 

 and the final residue of water was evaporated in a watch glass 

 and weighed. An exceedingly interesting feature of this latter 

 experiment was the finding of a water soluble calcium salt, in 

 small proportion, it is true, but still easily weighable and not to 

 be neglected. The results of such an analysis of a sample from 

 the Cedar Lake marl beds in Montcalm county, Mich., gave the 

 following results. The sample used was collected from a hole 

 made with a spade by cutting away the turf over the marl, then 

 taking out sufficient marl to be sure that there was no peat or 

 other surface matter present and the material used taken from a 

 spadeful thrown out from two or three feet below this level. 

 From this sample about thirty grams were taken and treated 

 as described above, and after the finer material had been sepa- 

 rated from the coarser by washing and drying, the latter was 

 passed through a set of standard gauge sieves, twenty, forty, 

 sixty, eighty, and one hundred meshes to the linear inch, after 

 which all shells and recognizable shell fragments, sand grains and 

 vegetable debris, up to the sixty-mesh siftings, were removed 

 and weighed separately. This gave the following grades : ( i ) 

 Material too coarse to pass through the twenty-mesh sieve, (2) 

 that held by the forty-mesh, (3) that held by the sixty-mesh, 

 (4) that held by the eighty-mesh, (5) that held by the hun- 

 dred-mesh, (6) that which passed through the hundred-mesh, 

 (7) that which was filtered out, (8) water soluble salts, (9) 

 shells, shell fragments, and miscellaneous matter. 



The following is the result of the analysis of Cedar Lade marl 

 made and graded as described : 



