102 Ernest W. S/,-e<ifs : 



1901. T. S. Hall and G. B. Pritchard discover Diplograptus 



in pebbles of Eocene (?) conglomerates neaj- Frank- 

 ston. 

 1901:. T. S. Hall identifies graptolites found by W. H. 

 Ferguson "in situ" at Balnarring, 10 or 12 miles 

 *outh of Moorooduc. Tetragraptus fruticosus and 

 other L. Ordovician forms are noted, ajnd the horizon 

 is described as Bendigonian. 



3. T/ie Age of the Sedimentary Rocks of Moorooduc. 



The following L. Ordovician graptolites were found by me " in 

 situ " in 1906, in slates three-quarters of a mile north of 

 Moorooduc railway station, and identified by Mr. T. S. Hall: — 



Didymogi'aptus caduceus, Salter. 



Tetragraptus serra (sensu stricto), Brongn. 



Diplograptus, sp. 



Trigonograptus, sp. 



Lasiograptus, sp. 



Glossograptus, sp. 

 Mr. Hall fixed their horizon as Upper Castlemaine, or possibly 

 Darriwill. The discover}' at Balnarring, and this later one at 

 Moorooduc makes it probable that all the slates and sandstones 

 of the Mornington Peninsula are of Ordovician age. 



4. The Metauiorphic Rocks. 



Near the intrusive granite highly altered micaceous slates 

 occur. One type is sjDotted, and contains andalusite showing 

 high extinction angles. In the other type the recrystallization 

 is more complete, although the l)edding planes are still tra-ce- 

 able. Rutile and tourmaline occur as accessory constituents, 

 while bleached biotite (?) muscovite and biotite are abundant. 



o. The Grano-diorite and Apophyses. 



The, Apophysi'S. — These are aplites and pegmatites. It is sug- 

 gested that the concentration of the micas neai- the walls of the 

 veins provides an illustration of the application of Soret's prin- 

 cijile to igneous intrusions. 



The Grano-diorite. — The rock is a hypidiomorphic, even- 

 grainod grano-diorite of Specific Gravity "2.09. In order of de- 

 creasing abundajnce the minerals present are : -Plagioclase, 



