2 54 THE GREAT BARRIER REEF. 



of earning a substantial competency open to, and turned to practical account by, all classes, as that 

 of bank-oyster culture in the Queensland oyster-producing districts of Moreton or Wide Bays. 

 With a nominal rental, payable for ground cultivated and occupied for a homestead, with a climate 

 that permits of dispensing with all but the most necessary form of raiment, and with fish procur- 

 able in such abundance as to substantial!}- minimise the butcher's bill, no more perfect terrestrial 

 elysium is probably at the disposal of small capitalists, having a sufficient means of main- 

 tenance for the first year or two that must elapse, before their oyster crops have increased 

 to a remunerative extent. 



That mode of oyster-growth which ranks next in importance to the bank series constitutes 

 what is known as oyster-reef. This, in its most typical form, consists of a solid mass of 

 oysters that may be several feet in thickness, raised to a higher level than the bank — the top 

 being exposed at about one-quarter ebb. As a rule, the upper crust, representing some five or 

 SIX to twelve inches in thickness, alone, of these reefs, consists of living oysters, the substratum 

 being composed of the dead shells of their ancestors. These reefs, in their most characteristic 

 state, rest simply on a clay or gravel basis, but are not unfrequently associated with a rocky out- 

 crop as their starting-point. Oyster-reefs, while formerly abounding in Moreton and Wide Bays, 

 are now represented in these localities in greatly diminished numbers. Their constituent 

 oysters, in consequence of their crowded growth, are of small dimensions ; but, on being broken 

 apart and distributed on the banks, they soon increase to a marketable size. Such reefs have, 

 consequently, formed one of the main sources for the collection of stock for culti\-ation on 

 the banks, and this to such an extent that few, if any, reefs are to be found in their pristine 

 massive condition throughout the oyster grounds of the southern district. 



A highly characteristic view of a typical virgin oyster-reef, selected from those which 

 occur in the neighbourhood of " The Narrows," between Port Curtis and Keppel Bay, is given 

 on Plate XL. The oysters in this reef are accumulated in a solid mass four or five feet 

 thick, their density being well shown by the portion which has been undermined by the current 

 and has broken away from the parent heap. The originally horizontal superficial area thereby 

 exposed, serves also to illustrate the rounded, or sub-orbicular, shape, previously alluded to, 

 that usually characterises the growth of oysters where massed together in this more northern 

 district. The basis of this luxuriant oyster-reef, and of others in the same locality, consists 

 chiefly of gravel and coarse sand, overlying a tenacious clay, larger pebbles or small drift 

 boulders, transported through the agency of flood currents, being here and there interspersed 

 among the general mass. 



Typical rock oysters (the bivalve occurring in masses attached to rocks) are well repre- 

 sented in the rocky outcrop with attached oysters at Burleigh Head, near the mouth of Tulle- 

 buggera Creek, a little to the south of Southport. The oysters growing under these condi- 

 tions, though smaller in size than the " bankers," are often deep, cup-like, and excellent in 



