386 



Coorongite. 



[The Alfred Flats, which many years ago, after heavy 

 floods, yielded a large quantity of coorongite, have been once 

 more submerged, in the lower portions, and fresh supplies of 

 this substance have appeared on the waters. Mr. A. C. 

 Broughton, who recently visited the locality, has supplied the 

 following notes, which were read at the evening meeting of 

 the Society on October 14, 1920.— Ed.] 



"To-day, on these new lagoons, a thick scum, like green 

 paint, is forming. This scum is drying on the water in places 

 to a semi-elastic substance, forming around reeds, it extends 

 laterally, growing over the surface of the water. On the 

 edges of the lagoons it is collecting along hundreds of yards 

 of shore-line to a distance of five yards from the shore. Tlie 

 drier portion can be scraped in with sticks. It is a nascent 

 substance in process of formation. Like green paint, a 

 quarter of an inch thick, it covers hundreds of square yards 

 of water, and as it drys it forms a skin like linseed oil drying 

 on an overturned mass of paint. This skin in places is yards 

 in area, and can be dragged along in sheets. It is driven by 

 the changing winds in streaks and films and hardening masse® 

 from shore to shore. 



"Last December (1919) it was practically unknown. In 

 February about four gallons were observed. In May it had 

 increased to hundreds of gallons. To-day it is there in 

 thousands of gallons. It is coorongite in process of formation. 

 On rises between lagoons, deposited as the water recedes, and 

 on the edges of the lagoons, the thin films of new coorongite 

 may be collected. Every stage from the green, liquid, paint-^ 

 like substance to the tough, elastic, sand-containing coorong^ite 

 may be observed. Scooped with the hand from the surface 

 of the lake this substance, within a few minutes, changes 

 before the eyes from a green liquid, which drips from the^ 

 fingers, to a brown, plastic solid. Large areas are now dry- 

 ing to sheets of coorongite, and is undergoing a change, both 

 in colour and in the nature of the substance. The conditions 

 are now very satisfactory for field work from a geological 

 aspect, and microscopical work from the biological side, to 

 determine facts in connection with this occurrence, which may 

 determine the origin first hand of the coorongite." 



