«3 



some ferruginous mineral which easily decomposes, leaving behind 

 •a reddish stain. 



Gem Stones. 



Whilst at Queenstown, Mr. Cox, of Antechamber Bay, brought 

 over a number of stones for my inspection which he had collected 

 on the Island. Amongst these were a few green and pink (rubel- 

 lite) varieties of tourmaline, transparent, of good quality and 

 likely to be of value as gems. Some of the specimens shown me 

 contained the precious tourmaline in a granitic matrix. T 

 regretted that my arrangements would not permit my visiting 

 the spot where they had been obtained 



Tertiary (Eocene). 



A very limited but interesting outlier of Eocene limestone 

 occurs at Cape Willoughby, near the lighthouse, exhibiting a cliff 

 face towards the sea The beds are about 15 to 20 feet in thick- 

 ness, resting unconformably on the granite. Immense boulders 

 of granite, as well as smaller ones, are included within the 

 Eocene beds, showing that the promontory was under the influ- 

 ence of marine denudation as far back as the Lower Tertiary. 

 These beds are sparingly fossiliferous, and have been greatly 

 leached. The lime thus extracted has been redeposited near its 

 source, forming a surface layer of travertine on much of the 

 ground w^iich forms the landward slopes. 



Post-Tertiary and Recent. 

 On the south side of the watershed in the main portion of the 

 Island, numerous lagoons, varying from fresh to salt, are a 

 marked feature. Murray's Lagoon, situated a little west of 

 Hawk's Nest, is one of the largest of these. It measures three 

 miles by two miles in extent, and has generally been sufficiently 

 fresh to be used for stock, but at the time of my visit it 

 was at its lowest known level, being sufficiently dry to 

 permit us walking into the centre. What appeared from a 

 distance to be a number of large stones lying near the centre of 

 the lake, proved on examination to be masses of tufaceous lime- 

 stone, a foot or two high. These accretions, which had evidently 

 been formed in the lake waters, consisted largely of brackish 

 water gastropods and the carapaces of entomostraca, cemented 

 together by carbonate of lime and other mineral matter. It is 

 evident that the lagoon has been at one time much larger than 

 its present margins would indicate, as a marly limestone, thickly 

 studded with the lake fauna3, occupies the surrounding rises, in- 

 cluding the knoll on which the Hawks Nest Homestead, occupied 

 by Mr. A. J. Florance, is built, at a mile distance from the 

 present edge of the lagoon. Similar fossiliferous marls were 



