233 



NOTE ON THE GUYRA LAGOON, N.S.W. 



By Leo A. Cotton, B.A., B.Sc, Junior Demonstrator in 

 Geology, University of Sydney. 



(Plate xxi.) 



While passing through Guyra on his road to Inverell, the 

 writer ^yas struck by the appearance of what is known locally as 

 the " Mother of Ducks Lagoon." From the history, as obtained 

 from local information, and from its physiographical aspect, the 

 lagoon promised to be of some scientific interest; and the follow- 

 ing note embodies the observations made in June last by the 

 writer and his brother, Mr. M. Cotton. 



GeogTa]-)hical. — The Guyra, or Mother of Ducks Lagoon, lies 

 beside, and to the west of, the Sydney to Brisbane railway line, 

 about 27 miles north of Armidale. It is oval in shape, the longer 

 diameter being about north and south. The greatest length is 2 

 miles, and the greatest breadth about 1^ miles. The town of 

 Guyra lies on the north-eastern shore of the lake, and has an 

 elevation of 4,330 feet above sea-level. With the exception of 

 Black Mountain, which has the same height, and Ben Lomond, 

 which is 143 feet higher, Guyra is the highest town on the New 

 England railway line. At Black Mountain, however, the sur- 

 rounding country is considerably higher than the railway station; 

 while at Guyra there is a difference in level of only a few feet 

 between the railway station and the highest point of the adjacent 

 country. 



The lagoon, when examined, was found to be hemmed in on all 

 sides by a basalt ridge of varying height. This ridge, on the 

 eastern side, rises about 50 feet above the bed of the lake; while, 

 on the northern and western sides, the height is about 60 and 70 

 feet respectively. On the south side of the lake the ridge is. 

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