354 C. A. SUSSMILCH. 



felder, as well as important modification of the pre-existing 

 drainage systems. 



8. The existing cycle of erosion which is still in its 

 youthful stage. 



NOTE ON the OCCURRENCE of MANGANESE in 

 SOIL and its EFFECT on GRASS. 



By F. B. Guthrie, f.i.c, f.c.s., and L. Cohen. 



[Read before the Royal Society of N. S. Wales, November 3, 1909.~] 



A sample of soil was received during last month from the 

 Secretary of the Dubbo Bowling Club representative of a 

 number of small patches occurring throughout the green 

 on which the grass had died down during last winter. It is 

 stated that the green was laid down five years ago, and 

 for the first three years was covered with a splendid coat 

 of healthy couch, but last winter and this winter it died in 

 40 or 50 small patches, ranging from a few inches to two 

 feet in diameter. As the green receives the same treat- 

 ment throughout, and as both the soil and the climate of 

 the district are admirably adapted to the growth of couch, 

 the problem presented was an interesting one, especially 

 as there was an absence of the sour condition and shallow- 

 ness of surface-soil frequently associated with such infertile 

 patches. A sample typical of the soil over the remainder 

 of the green and taken from places within three feet of 

 the dead patches was also obtained. A preliminary exam- 

 ination showed that both the soils were very similar in 

 chemical composition, but the fact was noted by one of us, 

 Mr. L. Cohen, that manganese was present in the soil on 



