2 HOLLAND: PECULIAR FORM OF ALTERED PERIDOTITE 



magnesite are constant characteristics of these peculiar exposures in 

 South India, and have given rise to the name "Chalk Hills/' applied 

 locally to the best known occurrence near the town of Salem. 



Whilst wuh a committee appointed to report in 1898 on the Mari- 

 kar.ave irrigation project in the Mysore State, the writer met with 

 the peculiar form of magnesian rock described in this note. The 

 rock is, so far as known, unique, and only this occurrence of it has 

 hitherto been recorded in South India. 



Its exposure at Huliyar in the Mysore State is a mere hummock 

 rising above the cultivated soil, which conceals its relationship to 

 the crystalline schists around ; but it is presumably part of a peri- 

 dotite intrusion, differing from the many others known in South 

 India by the peculiar form of alteration it has undergone. Like 

 other peridotite intrusions in the same area, it is accompanied by 

 masses of white quartz enclosing numerous cavities filled with car- 

 bonic acid, to which the writer has previously attributed the common 

 formation of secondary magnesite in these peridotites. 



The writer is very much indebted to Babu Baidya Nath Shaha, 

 M.A., a former pupil in the Presidency College, for material 

 assistance in the chemical work and for making the specific gravity 

 determinations. 



