306 BORING FOR MARL. 



if much boring is to be done, to have two augers, of equal bore 

 (or the short one something the larger), one of 8 feet length, and 

 the other 14. The shorter will be used first, and the longer only 

 when more than the depth of 8 feet is required. The auger is not 

 only useful to find the upper surface of the bed of marl, but also 

 to pierce the bed deeply enough to know whether it is thick and 

 rich enough to be worth the labour of uncovering and excavating. 

 Not more than about 6 inches depth should be bored at one time, 

 when the auger should be drawn up, and the cutting part cleared 

 of the adhering earth. If more boring is done at once than the 

 auger can lift completely, the bored hole is soon obstructed by 

 loose earth, and the design of the boring is impeded by the greater 

 haste of the labour. 



It is seldom that the shorter length of 8 feet will not be enough 

 for these uses of a marl auger j and the greater length of 12, or 

 at most 14 feet, will be ample. But, if for peculiar circumstances, 

 greater depth is required, additional pieces, of 4 feet each, may be 

 attached to and so lengthen the stem of the auger. The working 

 of so long an auger is excessively inconvenient ; when it has to be 

 drawn up so frequently. 



For the suggestion of this very useful tool, I was indebted to 

 Dr. William J. Cocke, who first introduced it and who, by its aid, 

 was enabled to find and to use extensively a very valuable bed of 

 marl under the low and level surface of his land (on Blackwater, 

 in Sussex), where its presence had not been reached or suspected 

 before. 



When it is desired to use an auger longer than 14 feet, by at- 

 taching one or more extra joints, the great inconvenience of lifting 

 and returning the auger may be much lessened by a simple con- 

 trivance introduced by Mr. Williams Carter, of Hanover. This is 

 to have a bench of narrow and thin plank, 7 or 8 feet long, with 

 legs of 8 or 10 feet. A hole large enough for the auger to turn 

 in freely is in the middle of the bench. As soon as it is necessary 

 to attach another piece to the stem of the auger, the bench is set 

 over the boring, with the hole immediately above, through which 

 the stem is passed. Thus, when the auger is lifted, it is supported 

 in its perpendicular position by the bench above. 



Such means as these, imperfect as they are, will be found more 

 convenient and effective in use, and much cheaper, than the heavy 

 and complicated augers used to search for coal. 



When I first began to apply marl, in Prince George county, it had 

 attracted so little observation, even as a matter of curiosity or singu- 

 larity, that the deposit was supposed by the few observers to be 

 limited to the few places where it was both exposed ai4lalso mani- 

 fest to the eye. These places were indeed very few in lower Vir- 

 ginia. For not only was the natural exposure of a section of the 



