(a) At hearings to determine the character of lands the claimants and witnesses will be thoroughly examined with regard to the character of the land; whether the same has been thoroughly prospected; whether or not there exists within the tract or tracts claimed any lode or vein of quartz or other rock in place bearing gold, silver, cinnabar, lead, tin, copper, or other valuable deposit which has ever been claimed, located, recorded, or worked; whether such work is entirely abandoned, or whether occasionally resumed; if such lode does exist, by whom claimed, under what designation, and in which subdivision of the land it lies; whether any placer mine or mines exist upon the land; if so, what is the character thereof, whether of the shallow-surface description, or of the deep cement, blue lead, or gravel deposits; to what extent mining is carried on when water can be obtained, and what the facilities are for obtaining water for mining purposes; upon what particular 10-acre subdivisions mining has been done, and at what time the land was abandoned for mining purposes, if abandoned at all. In every case, where practicable, an adequate quantity or number of representative samples of the alleged mineral-bearing matter or material should be offered in evidence, with proper identification, to be considered in connection with the record, with which they will be transmitted upon each appeal that may be taken. Testimony may be submitted as to the geological formation and development of mineral on adjoining or adjacent lands and their relevancy.

(b) The testimony should also show the agricultural capacities of the land, what kind of crops are raised thereon, the value thereof; the number of acres actually cultivated for crops of cereals or vegetables, and within which particular 10-acre subdivision such crops are raised; also which of these subdivisions embrace the improvements, giving in detail the extent and value of the improvements, such as house, barn, vineyard, orchard, fencing, etc., and mining improvements.

(c) The testimony should be as full and complete as possible; and in addition to the leading points indicated above, where an attempt is made to prove the mineral character of lands which have been entered under the agricultural laws, it should show at what date, if at all, valuable deposits of minerals were first known to exist on the lands.