110 CLASSIFICATION OF THE PUBLIC LANDS. 



tains workable coal from the area that does not contain workable 

 coal. The latter area is then plainly marked "noncoal," and if the 

 land is only to be classified and not valued a copy of the plat is made 

 on a blank township sheet to show accurately the coal land and the 

 noncoal land. This copy, after checking and proper designation, is 

 dated and signed by the members of the coal section of the board. 

 Its later history is the same as if valuation had been made. 



10. The tract or township may now be valued. The particular 

 steps at this point may vary greatly, depending on the complications 

 involved in the valuation. It may be that the coals are of a grade 

 so low that, like the low-grade lignites, regardless of their thickness, 

 they will be valued only- at the minimum. Or it may be that the 

 tract contains only one thin bed that lies flat and at slight depth, so 

 that the land may be valued at the minimum or perhaps at a uni- 

 form price. From these simple conditions there will be conditions 

 grading in complexity all the way to those found in such fields as, for 

 example^ the Rock Springs field of Wyoming, where there are three 

 groups of beds of coal of different age, character, and quality, each 

 group containing from six to eighteen coal beds, and where each coal 

 bed has been accurately traced by means of hundreds of measure- 

 ments made on the coal in each township, both along the outcrop and in 

 mines and drillings. Owing to differences in quality and thickness 

 coals have different depth limits. They may also vary in dip and may 

 be locally broken by faulting or by igneous intrusions. The value 

 of the land that is involved in these complications is computed by 

 using printed blanks that contain colmnns arranged to show not only 

 the observed data on each bed in each 40-acre tract, but also the com- 

 puted values of each bed, ending with the computed value of the 40 

 acres. This completed blank becomes part of the permanent record, 

 so that, if additional data are obtained or if for any reason the valu- 

 ation should be reviewed, it shows not only the field data but the steps 

 that have led to the final result. As values are determined they are 

 recorded on a blank township sheet and if the data are abundant and 

 complicated the coal boundaries may be drawn on transparent over- 

 sheets, on which the computed valuation prices are placed. This 

 sheet is properly labeled, dated, and signed by the members of the 

 coal section. 



11. As the land in a township is classified and valued memoranda 

 are prepared to show the basis for any criteria used, and all these 

 memoranda, with blank forms showing the computations and allow- 

 ances, are retained as " minutes " and, when reviewed and signed by 

 the members of the coal section, form a part of the permanent record. 



