J^"-'1 CuAPMAN, The Palceozoic t'lora. 141 



1918 J 



the latter case so entirely excellent are they as to call forth a 

 remark from one of our leading palaeobotanists that he pre- 

 ferred studying sections of petrified stems of cryptogams under 

 the microscope than similar structures in the living tissue. In 

 certain instances even the pollen grains from some of these 

 ancient palaeozoic forms have been chemically treated and 

 studied. 



Palaeozoic Floras. 



The older palaeozoic sediments of Australia, as in other parts 

 of the world, are very poor in any fossil remains which can be 

 with even a small degree of certainty assigned to the vegetable 

 world. Many of the so-called seaweeds or fucoids, as already 

 stated, may belong to the animal kingdom, or merely 'due to 

 the disturbance of the mud layer through animal or physical 

 agency. 



In the Lower Cambrian of South Australia the genus 

 Girvanella, probably one of the blue-green algae {Cyanophycece), 

 often forms a large proportion of the limestone. As at the 

 present day, these lime-secreting algse separated the CaCOg 

 from the waters of brackish-water lakes and salt lagoons of 

 the sea margin, and were thereby most important and effective 

 agents in making the rock-material of the earth's crust. The 

 South Australian Girvanella has its pellets formed of loosely- 

 rolled lime-coated cells, and a limestone of Upper Cambrian 

 age in the neighbourhood of Mount Wellington, North-East 

 Gippsland, which contains similarly-formed pellets, has the 

 tubes regularly and closely coiled. This Girvanella-\\vae<sione 

 from the Dolodrook River contains large, pea-shaped pellets, 

 the centre of many being occupied, as a nucleus, with an 

 ossicle of a crinoid. The presence of the crinoid fragments 

 would point to a deeper water origin than usual for this 

 calcareous alga ; on the other hand, it is just possible that the 

 crinoid remains were derived from an elevated rock mass situated 

 above the shore-line of the Cambrian sea. This rock was dis- 

 covered a few years ago by our fellow-member. Dr. E. O. 

 Thiele, who also brought to light an important trilobite fauna 

 of contemporaneous origin. The Upper Cambrian of Heathcote 

 has lately given evidence of what appears to be the remains 

 of an undoubted plant of a genus hitherto only known from 

 New York State, in America. This interesting specimen was 

 found by Professor Skeats : it is associated with a brachiopod 

 fauna. It is generically determined as SphenothaUus, named on 

 account of its wedge-shaped leaves. An interesting calcareous 

 alga, Epiphyton, has been lately described from the Antarctic* 

 It was found in a limestone pebble picked up by Wild in 85° S. 



* " Brit. Antarctic Exped., 1907-9, Geology," vol. li., 1916, p. 81. 



