The internal evidence — that afforded by the rock masses 

 themselves — appears somewhat conflicting. The intrusions 

 are clearly and violently transgressive, and as such might well 

 be connected . with orogenic movements ; but, on the other 

 hand, the physical conditions were such that differentiation 

 of the magma, was able to proceed as far as the albite syenite 

 stage, a state of things pointing to a prolonged period of 

 profound tranquillity before intrusion. 



In his presidential address to the Geological Society of 

 London in 1917 Harker assigns the potash and soda g^ranites 

 of Leinster to a late phase of the Caledonian folding, but here 

 the differentiation of the soda-rich rocks was effected by the 

 tangential pressure, with the result that they were iujected 

 as entirely separate units distinct and away from the main 

 granites. 



At Encounter Bay, on the contrary, the sodic rocks are 

 in the most intimate association with the normal granite. 



In the absence then of decisive internal evidence it is 

 best tentatively to consider the intrusions as having accom- 

 panied diastrophic movements which put an end to the Cam- 

 brian sedimentation. 



In his paper on the ''Basic Rocks of Blinman" Benson 

 inclines to tl-ie view that the dolerites are Palaeozoic; the 

 present investigation confirms that opinion of their age. 



VII. Contact Metamorphism. 



The metamorpbism to be seen in the neighbourhood of 

 the igneous rocks is partly anterior to and partly a result of 

 the intrusions. About six or seven miles up the Inman River 

 the sediments have plainly been altered and to some extent 

 recrystallized,.and this can only be attributed to metamorphic 

 forces of a regional character. Owing to the overburden of 

 glacial material it is difficult to trace zones of metamorphism 

 continuously for any considerable distance inland from the 

 contact, and as a great deal of time was not spent in exam- 

 ining the schists the author is not in a position to present a 

 complete account of the metamorphism. The following notes 

 of observations made and specimens collected will, however, 

 indicate the interesting nature of the contact effects, and may 

 serve as an introduction to more detailed work, should oppor- 

 tunity for further investigation arise at a future date. 



The contact metamorphism is best studied in the neigh- 

 bourhood of Kosetta Head, since nowhere else is a section 

 exposed of the junction between the invading and invaded 

 rocks. Still a certain amount of information can be gained 

 from the, included blocks of country rocks in the granite of 



