Ojpal Nodules at Richmond River. 



169' 



Description of Thallophyte. 



The appearance of this organism in a thin section under a 

 moderate magnification (1 inch obj.) is that of a matted, fila- 

 mentous weed, reminding one of the threadhke conferva of lakes 

 and streams. The filaments are usually cylindrical, and 



Fig. 1 Cladophora richmondiensis , sp. nov. 



constricted at the nodes or partitions. The partitions are spaced! 

 at fairly long intervals, varying from about three to six times 

 the diameter of the filament. The cell-walls show a well marked 

 outline of the exterior and interior, which character distinguishes 

 them at once from any spicular body, in which there is a strong 

 surface refraction. 



Small rounded bodies in aggregates are seen in the matrix,, 

 which may be referable to tetraspores. The average diameter 

 of the cells of the thallus measure 46 /x. 



That this fossil form is of the confervoid type of cell-struc- 

 ture, and not referable to the blue-green algae, is very clear 

 from the distinctness of the cell-walls, which are sharply out- 

 lined and not hazy as in the encrusted cells of the Cyanophyceae. 



