212 J. T. Jafson: 



Prof. MoCoy, from the iDalseontological evidence, was enabled to 

 prove the Silurian age of the older sedimentary^ formations, and 

 to suggest! that fossils from certain localities were indicative of 

 the base of the Upper Silurian (Silurian), a suggestion that Mr. 

 Chapman in his Appendix to this paper, by his determination of 

 their Melbournian age, now confirms. There was not sufficient 

 material to indicate the geological structure of the rocks, nor 

 to subdivide them palseontologically. 



Since the work of the Sui^vey, many more sections have been 

 revealed by road cuttings ; and these have enabled me to 

 collect many fossils and to record observations by which the 

 general geological structure may be ascertained, and the beds 

 subdivided. 



LiTHOLOGICAL CHARACTERS. 



The rocks throughout the area are O'n the whole extremely 

 uniform in general lithologioal characters. They varv from thin 

 bedded shales and mudstones of very fine grain to fairly thick 

 bedded, coarse-grained micaceous sandstones, which are often 

 siliceous. The finer grained rocks are generally rubbly, often 

 conchoidal in fracture, soft under the hammer, generally contain 

 little mica, and possess a considerable variety of colours. Tliey 

 are, if anything, characteristic of the Melbournian division of 

 this area. The coarser grained rocks often contain much mica, 

 are usually brown or yellow in colour, are frequently mottled, 

 and possess more pronounced joints than the finer grained series. 

 They are more indicative of the Yeringian division in this 

 district. 



The only distinctive bands are the sandstone, noted by Mr. 

 Chapman under seiction V" in the Appendix, as containing starved 

 forms of Camarotoechia decemplioata, Sow. sp., and a shelly 

 limestone. Tbe former is found forming a line of reef contain- 

 ing small quartz veins, on a hill to the south of Mount Phillippi. 

 The same kind of rock (but so far as I have observed, witliout quartz 

 veins), containing similar fossils, is found at Mount Phillippi, 

 and also at section XIII. As the occun*ence>s a.t the line of reef 



1 Quarter Sheet, 3 N.K. 



2 This a?i(l the other iiunibiMs in lioiiiaii luiinerals refer to tlif fossiliferoiis, sections 

 inarkid on the aecompanyinj;- map. In tlie .Ajipendix tlie same numbers are used to 

 indicate the same sections. 



