. The prospector's field-book and guide in the search for and the easy determination of ores and other useful minerals. excluded. Such an error may, however, occur whenthe outcrop is covered with loose masses of earthand rock, to the base of which the oil exudingabove flows down hidden, and escapes further belowby some accidental cause. A vein-like occurrence of oil will not show the 260 PROSPECTOR S FIELD-BOOK AND GUIDE. above-mentioned conformities with the characteristicconcordant strata. Such an occurrence presupposesa fissure, which is generally connected with a throwof the strata. This i
. The prospector's field-book and guide in the search for and the easy determination of ores and other useful minerals. excluded. Such an error may, however, occur whenthe outcrop is covered with loose masses of earthand rock, to the base of which the oil exudingabove flows down hidden, and escapes further belowby some accidental cause. A vein-like occurrence of oil will not show the 260 PROSPECTOR S FIELD-BOOK AND GUIDE. above-mentioned conformities with the characteristicconcordant strata. Such an occurrence presupposesa fissure, which is generally connected with a throwof the strata. This is most frequently establishedby the fact that a characteristic stratum suddenlyends and does not reappear in its natural continua-tion, but either to the right or left, or higher orlower. If two or more such points of disturbance Fig. have been found, their connecting line is the out-crop line of the fissure, Fig. 62. If this line passesthrough the outcrop a, or if several outcrops lie init, a vein-like occurrence of oil must be inferred. However, sometimes the oil occurs in a maze ofsmaller and larger fissures. This is shown in theconstruction by the fact that in the presence of sev-eral outcrops a linear distribution of the same can-not be recognized, and that the combinations yield PETROLEUM, OZOCERITE, ASPHALT, PEAT. 261 the most varying results, according to whether ex-ploration is carried on from the one or the otheroutcrop. Such occurrence presents uncommon dif-ficulties in prospecting. It need scarcely be mentioned that in prospectingfor oil, it is of great importance to hunt up and mapthe anticlinals and their saddles, as well as faults. The directions here given for prospecting mayhave to be modified according to local a sufficient preliminary knowledge of geology,any difficulties will, as
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