of the Buchan District 27 



with the Buchan, I made further observations. I found 

 the Diabase rocks near Moore's Crossing to be rough, 

 massive, and dark coloured. They weather dark brown, 

 and are often so much decomposed as to be well described 

 by the old name of " claystone porphyry." Further down 

 the river they are very vesicular or amygdaloidal, or again, 

 crystalline or microporphyritic. These rocks generally are 

 traversed in all directions by veins of calcite and of red 

 jasper, which also occur singly or together in geodes. In one 

 place I observed appearances strongly suggestive of bedding ; 

 but the alterations in the rock were there so great that I was 

 not able to determine this point to my satisfaction. 



As the Buchan limestones have been generally denuded 

 from these rocks along the river, the traces of their former 

 existence are only observable in the extensive alterations 

 which their contact with the igneous rocks has given rise 

 to. The reactions have, however, been clearly subsequent 

 to the consolidation of the Diabase rocks, and are, therefore, 

 not to be confounded with ordinary " contact effects." 



At about forty chains distance from the junction of the 

 two rivers a change of rocks is evidenced by the different 

 surface features, and an alteration in the nature of the soil, 

 and the character of the vegetation. At the junction itself 

 the rocks can be seen, and it then becomes apparent that 

 the formation is one of the areas of Lower paleozoic (silurian ?) 

 mudstones and sandstones in a greatly altered condition. 

 The evidences of folding and contortion are very strong, and 

 the rocks strikingly resemble some of the forms of meta- 

 morphic contact schists. Their present position alongside of 

 the Buchan beds must be due to faulting, as they are highly 

 inclined , whereas the former are comparatively horizontal. 

 One sample examined under the microscope showed me the 

 familiar appearance of a metamorphic contact schist. It 

 consisted of fragments of quartz and felspars, set in a paste 

 (mud) which had been converted into micaceous substances. 

 Another sample of one of the most contorted varieties I 

 found to be almost entirely mica — some of the larger flakes 

 being evidently muscovite. 



On leaving Moore's Crossing the line of section follows 

 throughout the direction of the track, leading thence to 

 Buchan. The Diabase porphyrites continue from the 

 river to near the summit of the range, where come in felsitic 

 rocks having the usual appearance of those near the 

 Murendel River. These continue along the track to the 

 Murendel River, but their continuity is broken in three 



