,566 ISLE OF MAN. GEOLOGY. LIMESTONE. 



bear the marks of partial fusion. Considering the different 

 qualities of the respective substances, there is a perfect 

 correspondence between the changes in both cases. 

 There is however one important circumstance present in 

 Sky, which is here wanting, at least throughout the greater 

 part of the space where the unstratified limestone occurs. 

 The existence of overlying syenite in that island, was there 

 supposed to offer a solution of the phenomena in question ; 

 as the passage of trap veins has been shown, in other 

 instances, to produce analogous effects. Although the 

 veins of Scarlet point may be supposed to have caused 

 the irregularity and change of structure there apparent 

 in the limestone, no such veins exist throughout the greater 

 part of the space where the unstratified limestone occurs. 

 Nor is even granite here visible-, the calcareous rock 

 being in contact with the argillaceous schist wherever it 

 admits of examination. No apparent and analogous cause 

 therefore exists in the Isle of Man, for that change in 

 the nature of the limestone, which, in Sky, is supposed 

 to have been the consequence of the presence of syenite. 

 Yet there are circumstances, in the characters both of the 

 sandstone and the schist, which seem to indicate that they 

 have also undergone some analogous changes ; differing, 

 it is true, but these differences depending on the relative 

 nature of the different substances. 



It will be remembered that, in the vicinity of the schist, 

 the sandstone of Peel possesses an unusually indurated 

 texture ; and that the two rocks are fractured and inter- 

 mixed at the junction, while the characters of both are 

 changed. In other places, the schist presents similar 

 marks of some posterior influence, by which it has been 

 fractured where 'in contact with the secondary strata, and 

 its iron oxydated to redness. It is easy to imagine that 

 such effects might, in these two rocks, be produced by 

 the same causes which were capable of destroying the 

 original forms and characters of the stratified limestone. 



Thus the arguments must remain ; as in attempting to 



