Art. IV. — Notes on the Lilydale Limestone. 



(With Plates VIII and IX.) 



By Rev. A. W. Cresswell, M.A. 



[.Head July 14, 1892.] 



The limestone formation of Cave Hill quany at Lilydale, 

 the subject of this paper, is, for the most part, a hard semi- 

 crystalline marble deposit, wedged in between hard qiiartzite 

 on the one .side, and soft shales and mudstones on the other; 

 and has for many years ])ast been recognised by Professor Sii' 

 F. M'Coy and others as of Upper Silurian age, of about the 

 horizon of the English Wenfock, fi'om an inspection of its 

 contained fossils. The limestone strata dip to the east at 

 varying angles of from 35° to 50°, the strike being nearly 

 north and south magnetic, var3'ing, however, on the east 

 side of the quarry to as much as 18° east of magnetic north. 

 The exact thickness of the limestone is not as yet known, 

 for it does not naturally crop out on the surface, but is only 

 artiticially exposed by quany ing. As early as 1850, the 

 late director of ouj- Victorian Geological Survey, Mr., now 

 Sir A. R. C. Selwyn, speaks* of the limestone as known to 

 exist, but as only discoverable b}^ a well-like hole on the side 

 of the hill, leading into a cave hollowed out in the rock, and 

 sloping down to a depth of 120 feet, with stalactites, &c. (a 

 specimen of which is shown). But about fifteen years ago, 

 a quarry was excavated in the limestone on the side of the 

 hill, and the opening to the cave is now covered up with 

 debris, and is inaccessible. 



The progress of quarrying has now proved the limestone 

 to be of much greater thickness than was at first reported.-f- 

 The measurement across the outcrop is about 5 chains, or 



* Eeport on Geological Structure of Colony of Victoria : Basin of 

 Yarra, &c., 1856. 



t " Victorian Naturalist," 188o, II, No. 3, p. 35. 



