April, 1910.[ THE VICTORIAN NATURALIST. 193 



Victorian fossi! Foraminifera is the direct light it throws upon 

 climate and depth of sea bottom. As regards the first, the 

 Oligocene and Miocene, as elsewhere, enjoyed a sub-tropical 

 climate, many forms, now only found in coral areas, being typical 

 of our Balcombian and Janjukian strata. In later times, towards 

 the Pliocene (Kalimnan), the climate became much colder and 

 perhaps even of lower temperature than at the present day. 



As regards bathymetrical limits, certain forms indicate a 

 shallow, shelving sea bottom, others a deep water habitat ; while 

 still others indicate estuarine conditions, with intercalated fluvia- 

 tile influence ; and even a dune-sand deposit skirting a coastal 

 margin, as shown by the occurrence of polished sand and shells 

 due to aeolian action. 



Of older foraminiferal deposits there is very little to say, so 

 far as our present knowledge goes. There are traces of what 

 appear to be foraminiferal tests in the Devonian limestones of 

 Gippsland. In the Silurian limestone of Cave Hill, Lilydale, the 

 sandy coiled tests of Ammodiscus are not uncommon. 



Some Practical Hints. 



On the Collection of Recent Foraminifera. — The whitish tide- 

 streaks left on a gently sloping shore by the retreat of the water 

 consist of Foraminiferal shells, mostly dead, echinoid spines, fry 

 of mollusca and seeds. Sometimes a particularly pure gathering 

 of littoral Foraminifera may be made by scraping the surface of 

 the sand carefully and lightly with a broad, sharp-edged spoon, 

 the square-edged lid of a mustard tin or a bent up stiff card. 

 The material obtained can be filled into a tin, and should be 

 washed from saline matter as soon as possible. 



The silt from estuarine mud deposits often contains a rich 

 assemblage of the beautiful lagena shells ; and these, if they 

 be empty, can be separated by throwing the dried material on to 

 a bowl of water, when they will float, leaving the heavier, minute 

 sand particles to sink. This floating film of shells can be poured 

 off into a second vessel and the water siphoned away, so that 

 one is enabled to dry off the shelly material. Another method is 

 to skim off the floating shells on strips of blotting paper, 

 which can be easily dried. 



A good method of procuring quantities of living Foraminifera 

 is employed by Mr. J. J. Lister. A double sieve is used, the top 

 being of horse-hair, which will allow the Foraminifera and little 

 else to pass through, the lower being of bolting cloth, which 

 retains the Foraminifera. This sieve is taken to low-tide pools, 

 where the sea-weed is washed into it, generally with good 

 results. 



Dredgings from deeper waters are often rich in these micro- 

 scopic shell deposits, especially in the proximity to currents and 

 where there are calcareous rather than igneous rocks in the 

 neighbourhood. 



