30 Economic Geology. 



ency of the former has in many cases been materially inter- 

 fered with, in others entirely destroyed. There is, accord- 

 ingly, no cause of failure in boring operations more faithful 

 than the occurrence of these dislocations, or " faults." Their 

 effects are various ; they either wholly interrupt the percola- 

 tion of the water through the porous beds, or open up a 

 passage for it interiorly, so that it descends deeper into the 

 earth, or they throw it to the surface in the form of springs, 

 in localities where it may be of comparatively little import- 

 ance. Much care is therefore necessary in ascertaining the 

 existence, nature, and direction of these dislocations in the 

 vicinity of any locality intended for an Artesian well, and 

 although they are frequently concealed, yet the character 

 of the adjoining country, the disposition of the strata, 

 and above all the existence or non-existence of surface 

 springs, will afford materials for the formation of an esti- 

 mate of the probabilities of success. With reference to 

 the last mentioned circumstance it has been remarked, 

 that powerful springs are almost invariably indications of 

 extensive faults, and in the examination of large tracts of 

 country no single instance has been found in which the one 

 occurred unaccompanied by the other. Faults, it is true, 

 constitute a most important part of the general hydraulic 

 machinery of the globe, but their influence on the particular 

 system under remark may be most injurious, and to estimate 

 duly their effects in deranging the conditions required for 

 the effective action of an Artesian well, is a most important 

 preliminary step to commencing the actual work. 



Observations on the dip or direction of inclination of 

 the strata should also be carefully made, and should be 

 extended over a considerable portion of the adjoining 

 country. The inclination of the beds will necessarily deter- 

 mine the course of the percolating water, and if these are 

 exposed either by natural or artificial sections, in the neigh- 

 bourhood of the locality under examination, then the water 

 will discharge itself there, and a well sunk without reference 



