849 



NOTE ON THE OCCURRENCE OF A LIMESTONE- 

 FLORA AT GROSE VALE. 



By W. M. Carne. 



Instances of the part played by geological formation in* the 

 distribution of species and the formation of plant-coQimunities 

 in New South Wales, have been put forward from time to time, 

 by various botanical and other workers. So far as the writer is 

 aware, no record has yet been published dealing with the effect 

 of a lime-deposit on vegetation. 



The present note deals with an interesting, though small, patch 

 of vegetation occurring on an outcrop of a limestone at Grose 

 Vale, Hawkesbury District. The deposit is to be found below 

 Box Hill, and is followed by the Horseshoe Bend Road, which, 

 running N.E. and S.W., joins the main Kurrajong and Grose 

 Vale Roads. It is on the eastern slope of the hill, which curves 

 to form a natural amphitheatre sheltering orchards and other 

 cultivated areas. At about 100 yards from the Grose Vale end, 

 and following the road for about half a mile, nearly to what is 

 known as Lookout Hill, is the outcrop, with its vegetation, which 

 is so distinct as to be noticeable against the hillside from several 

 miles away. Another small deposit, denuded of timber, occurs 

 near the church, about half a mile from Kurrajong Road. The 

 deposit is about 800 feet above sea-level, and about 8 miles by 

 road from Richmond. 



The dense growth of trees, entangled with many creepers, and 

 the absence of Eucalypts, resembles that of the luxuriant gully- 

 brushes of the eastern slopes of Kurrajong Rang(); or, perhaps, 

 more nearly, those on volcanic soils, such as at IMountain Lagoon, 

 Mount Wilson, or even of the Illawarra slopes. Above the road, 

 this vegetation extends nowhere more than 20 yards, while, on 

 the steep slope below, its width has been much greater, probably 

 owing to the soil having been washed down from the outcrop 



