230 THE AMERICAN MONTHLY [July 



the bottom and sides of the soap-bowl. After each tilling 

 up and pouring- oif of the water, the trituration must be 

 renewed to remove another increment of clay at each 

 pouring off, which will be liberated from the heavier 

 sediment at each filling up with water. If at this stage 

 a small test should be made, the presence of unreduced 

 particles of clay would still mask the fossil contents, and 

 for this reason it would then be necessary to pour off as 

 much water as possible, at the same time collecting the 

 sediment into the smallest compass in the bowl, held 

 slanting; at which point the further precaution should be 

 taken of removing a few mor^i drops of water from the 

 mass. The next step is to have at hand a piece of com- 

 mon blotting or bibulous paper upon which the sediment 

 is decanted; the blotting paper will at once absorb the 

 remainder of the water, leaving a little cake or pellet on 

 the paper, freed from any excess of water. This pellet 

 is then removed by slipping a knife blade under it and 

 depositing the same on the middle of the rubber strip, 

 next with a rubbing and spreading pressure exerted by 

 the ball of the thumb, the pellet of clay is continuously 

 triturated by straight strokes over the major part of the 

 surface of the rubber pad or square. When this rubbing 

 (gathering together) and re-rubbing has been kept up 

 for a sufficient time, it will be noted that the material 

 has again apparently returned to a liquid condition 

 and the minute lumpy particles have been dissipated. 

 The material is again transferred to the soapbowl to 

 which at first a rather small quantity of water is added, 

 §0 that the pasty mass may be distributed evenly in the 

 water by the finger. The bowl is then filled with water 

 and the decantation or pouring off resumed, and it will 

 then be noted that the remaining sediment is distinctly 

 visible through the small quantity of water retained and 

 an absence of further milkiness on an additional agitation 



