AiiT. XVII I. — Tlie Geology of Coimdidai. 



Part II. 



The Silurian and Glacial Beds. 



By Graham Office u, B.Sc, aud Evelyn G. Hogg, M.A. 



With Appendices by C. AV. De Vis, M.A., and T. S. Hall, M.A., 

 on the Marsupial Bones of the Coimaidai Limestone 

 and the Graptolites of the District respectively. 



(With Plates VIII. and IX.). 



[Bead lltb November, 1897]. 



As stated in Part I. of the present paper a short account of 

 the glacial beds of Coimaidai was communicated by us in con- 

 junction with AJr. L. J. Balfour, B.A., to the A.A.A.8. at its 

 Brisbane meeting in January, 1895. Since that time we have 

 had opportunity for studying in detail the geology of the district, 

 and though further acquaintance has led us to modify our opinions 

 in n)inor details, it has on the whole contirmed the conclusions 

 at which we had then arrived. 



The Lower Silurian beds which form the base of the series ex- 

 posed in the district consist mostly of sandstone, tine- and coarse- 

 grained, slates and shales : they are highly inclined throughout 

 the area and maintain a fairly constant strike of N. 10° E. The 

 only fossils met with in the district are Graptolites, a description 

 of which lias been kindly communicated to us by Mr. T. S. Hall, 

 M.A., for which see Appendix B. 



In a section of the Silurian exposed in the Pyrete Creek, near 

 Wightman's farm, a thin bed of conglomerate is intercalated 

 between coarse grained sandstones; the included ]oebbles consist 

 of well-rounded white quartz ajid the matrix is made up of quartz 

 grains. The bed is lenticular in shape and rapidly tliins out at 

 tiither end ; its length is about 20 feet, and its greatest thickness 

 not more tlian eight inches; it is the only bed of its kind known 

 to us in the district. 



