Ordovlcian Rocks. 51 



I. Area. 



The area over which these observations extend includes about 100 

 :square miles. Its approximate boundaries are, on the north and 

 east the granite massif of Mount Alexander, on the west the Muckle- 

 iord Creek, and on the south a line drawn from Strangways through 

 Tarilta, Glenluce, and Fryerstown to tlie Elphinstune Tunnel on 

 the Melbourne to Echuca railway. 



II. Previous Workers. 



A. R. C. Selwyni as early, as 1853 made a section of the beds from 

 the Campaspe to the Loddon along a line passing through Mounts 

 Alexander and Tarrengower. 



The late Dr. T. S. Hall2 in a paper to this Society on the Geology 

 of Castlemaine (1894) shows that the differences between the grap- 

 tolites of the various outcrops are due to the stratig'raphical rela- 

 tion of the beds. From the palaeontological evidence he was able 

 to demonstrate their succession and outline six zones. He also gives 

 a general account of the geology of the district. His paper deals 

 particularly with the area to the south and the east of the town of 

 €astlemaine and forms the basis for all later palaeontological work 

 on this area. The general lines of the classification of the graptolite 

 zones indicated in this paper have since been independently con- 

 firmed in other districts. The writer during the years 1912-1915 

 examined all but three or four of the outcrops previously visited 

 b>y Dr. Hall, and is able to attest the accuracy of the deceased 

 worker's observations. One who has traversed the rough hills 

 around Castlemaine can thoroughly appreciate the painstaking and 

 accurate work which, without the aid of present-day facilities for 

 travelling, Dr. Hall cari'ied out over twenty years ago. The difficul- 

 ties in the way have resulted in a scientifically fertile field lying 

 idle for more than two decades. 



Mr. W. Baragwanath3 deals with portion of the area in Memoir 2 

 of the Geological Survey of Victoria. Axial lines are plotted and 

 a section given showing the succession of the strata. The section is 

 evidently based mainly on observed dip. No particular section line 

 is marked on the map, but the section appears to be along a line 

 from Forest Creek through Quartz Hill to Gaol Hill. If so, it errs 

 in not showing a ge-anticline on the Cemetery Reef where the lowest 



1 Geology and Mineralogy of the Mt. Alexander Goldfield, Pari. Papers, 1853-4, vol. ii., et 

 -Q.J.G.S., vol. X. 



2 Proc. Roy. Soc. Victoria, vol. vii. (n.s.), 1894. 



3 Castleniaine-Chewton Goldfield. Mem. 2 Geol. Surv. Vic. 5a 



