158 F. L. Stillwdl 



Silurian. 



This sedimentary series is here, as throu^^hout the Melbourne 

 district, the fundamental rock. It is found well exposed in the 

 stream valleys and beds, and is represented on the map as cover- 

 ing a fairly large area. This area is mainly well-grassed country, 

 but exposures here and there indicate its extent. It is bounded 

 on the north by the granite, on the north-west by the older 

 basalt, and elsewhere by tertiary deposits. Lithologically they 

 consist of a series of sandstones and ujudstones, and a few shales 

 with a strike about 42 deg. E. of N. Observations of the dips 

 lead to the statement that most of the area is part of two 

 dissected anticlines whose axes are represented by the dotted 

 line on the map. On the quarter sheet these rocks are noted as 

 '■ yellow and white argillaceous sandstones, Tvith mottled red, 

 yellow and brown ferruginous beds and olive-coloured shales." 

 It is also stated that *" in places along the Broadmeadows Creek 

 8 to 10 feet of drift composed of angular fragments of granite, 

 trap and silurian, rests on the above and passes upwards into 

 the soil ; slightly sandy nodules like orthoceratites and 

 gasteropoda are found on both sides of the creek in the shales." 



With regard to the precise age of these rocks there is no 

 direct evidence, as no fossils were found in this area. Silurian 

 fossils are recorded from Keilor, live miles to the S.W., and as 

 the lithological characters and strikes approximately agree, we 

 can assign a silurian age to the Broadmeadows series. 



Distribution and General Characters of the Granite. 



Tlie granite hill of Gellibrand forujs a prominent feature of 

 the area. Being partially wooded, it stands out in contrast with 

 the treeless basalt plains and the cultivated and well-grassed 

 silurian country. Though only about 500 feet high, an exten- 

 sive view may be had from the summit in several directions. 

 To the south stretches out the city of Melbourne and the shores 

 of Port Phillip. To the north-east lie the Plenty Ranges, and to 

 the north, closer at hand, are low volcanic hills and other 

 granite hills. To the north-west lies the distant mass of Mt. 

 Macedon, with the outstanding plug of solosbergite, known as 



