136 OUT1.IM S OF FIELD-GEOLO PART I 



of a line of fault between the stratified rocks and the 

 crystalline masses. The sections in the n< 

 similar. It will be observed that while the general order 

 of the strata is the same as we go eastward, lower and 

 lower portions of them successively come into view below 

 the band B^ which was the lowest definitely marked in 

 the first section. In the third stream, a still lower band 

 (A) makes its appearance, while in the fourth there 

 emerges below A a yet greater breadth of underlying 

 strata. It is by thus piecing different contiguous 

 sections together that the order of strata in a district is 

 made out The angle of dip in the second stream rises 

 as before towards the higher ground inland, until angles 

 of 70 to 80 are reached. In the third stream similar 

 evidence is obtained, only here a little ambiguity seems 

 at first to arise from the fact that the strata, after 

 gradually becoming vertical, dip as it were into or below 

 the granite. This in reality is a reversal of dip. The 

 strata have not only been thrown on end, but actually 

 bent back upon themselves, so that a section of them at 

 that place would show such an arrangement as is given 

 in Fig. 39. No more convincing evidence of the existence 

 of a powerful fault could be given. 



Now, having put these various data upon our map, we 

 see that the point of junction between the two kinds of 

 rock crosses the streams in a tolerably straight north- 

 easterly line. There cannot be any doubt that the 

 junction is a fault ; for ist, there is no trace of any con- 

 glomerates or other indications of an original base to the 

 formation, lying upon and wrapping round the granite ; 

 on the contrary, the remarkably straight boundary-line is 



