From the Upper Yarra District 223 



' Bryozoa or Moss Corals, — These "creatures occupy a 

 higher position in the organic scale than the simpler-formed 

 polypes with which they were formerly associated. Many 

 hundreds of microscopic fossil species have been discovered 

 within the last few years. The shells^ or outer tunics, enter 

 into the composition of chalk beds, compact limestone, and 

 sea sand, as well as the sands of the deserts. These fossil 

 forms, many species of which arc still living, are mostly 

 microscopic ; those which are visible resemble minute grains. 

 Those which at present engage our attention belong to the 

 genus Celaria^ and, I am of opinion^ are closely allied to 

 (7. Loricata. 



A second species of Bryozoa^ which, however, I am unable 

 to distinguish, also occurs in company with those mentioned. 

 This variety forms rounded columns, about an eighth of an 

 inch in length, with fine ribs or threads passing longitudinally 

 downwards. 



The few forms which I have been^able to detect in the 

 specimens forwarded to me lead me to the conclusion, that 

 the strata in which they occur belong either to the uppermost 

 Cambrian or to the lowest silurian formation. It is highly 

 remarkable that these rocks are found in an auriferous locality, 

 and in the immediate vicinity of our earliest gold-field. 



In conclusion, I may beg to observe, that fossil remains of 

 the oldest Neptunic era may be obtained in abundance at 

 certain spots in an extensive line of district eastward of 

 Melbourne, and which would well repay the trouble of the 

 enterprising man who would institute a search for them. 



Subsequently to writing the above, I have discovered by 

 a minute examination, in the rocks referred to, the forms 

 exhibited in the plate- The palaiontoiogical description of 

 these wiU form the subject of another paper. 



Art. XVIII. — Practical Remarks on Hydrometry, By 

 CliEMBNT HODGKINSON, ESQ, C. E. 



The contradictory results of the hydrometrical observations 

 made by different persons in this colony, had induced me, 

 some weeks ago, to give notice of my intention to submit to 

 this society a paper embodying my objections to the mode of 

 guaging streams often adopted by the engineering profession, 

 and the result of my own experience in these operations. 

 Kecent domestic afflictions had, however^ caused me totally 



