554 W . N . BENSON. 



including olivine basalt. They are therefore cognate 

 inclusions in Harker's sense of the term, homceogenous in 

 Lacroix' classification. They belong to homologous and 

 antilogous groups of the allomorphous division of such 

 inclusions. They present many features of exceptional 

 interest, both in their mineralogical composition and manner 

 of alteration. One rock type containing granophyric inter- 

 growths of pleonaste and pyroxene and free from magnetite, 

 though common at Dundas, does not appear to have been 

 found in any other part of the world. It is well worthy of 

 further investigation. Well crystallised quartz, amethyst, 

 pyrites, calcite, siderite, aragonite and barytes may also be 

 found at Dundas. 



These notes cannot be considered exhaustive. Bach visit 

 to the Dundas quarry yielded new material showing fresh 

 features, and as the work of excavation progresses much 

 more may be revealed. 



Acknowledgements. 

 My thanks are primarily due to Mr. T. G. Taylor, who 

 on his departure for England, handed over to me his notes 

 and collections from the Dundas quarry, and to Mr. 0. A. 

 Sossmilch who withdrew in my favour from the work on 

 Hornsby. To Professor David I am ever indebted for his 

 kindly interest in my work and valuable information and 

 advice. Dr. Woolnough has given me useful advice in the 

 petrology, Mr. Dim help in obtaining reference to some of the 

 literature, Mr. Card in giving much information with regard 

 to the less known occurrence of inclusions in New South 

 Wales. Messrs. C. A. Siissmilch, R. E. Priestly, J. L. 

 Froggatt and H. G. Gooch, have allowed me to examine 

 their slides of Dundas rocks, and I have also availed myself 

 of the collections of the Sydney and Adelaide Universities 

 and the Sydney Technical College. I am especially indebted 

 to Mr. J. Allen Thomson, who has given me the benefit of his 



