166 
[vOL. XII. 
Records of the Geological Surveg of India. 
above the sui’face of water, like Asterophyllites. In the Indian plant, however, 
the leaf whorls are incomplete, there being always only six leaves, on one side 
of the joint, arranged in three pairs ; the stalks are thin in comparison with the 
size of the leaves, showing perhaps that the Trimjgia was a plant which floated 
on the surface of water. 
In my paper on some fossil plants from Raniganj,' although placing the 
Indian form with Splienophyllum, I j)ointed out all these differences, and distin¬ 
guished two groups of Sjjhenofhyllum. 
At present I would formulate my view in the following manner;— 
JEQJJISETACEA]]. 
Calamaeiej). 
Group: Sgdienojjhylloidem. 
«•—Leaf whorls complete round the joint; number of leaves variable ; leaves 
of the same size and shape in the same whorl. 
The ti’ue carboniferous Splienophylhmi. 
h .—Whorls incomplete on one side of the joints; number of leaves six, 
arranged in three pairs, of which each differs from the other in size 
and partly also in shape of the leaves. 
The Trizygia of the Indian coal-beds. 
In this sense Trizygia may be considered as representative of the carbonifer¬ 
ous Sficyiofiylhim, but is an independent genus. 
We have therefore— 
Phyllotlieca, representing in the fossil flora the living Equisehim. 
SeMzoneura, representing perhaps the genus A&terogliyllites of the palseozoio 
formation. 
Trizygia, representing the genus Sfhenoghyllum, although differing from it. 
On Mysoein and Atacamite from the Nelloee District, ly F. R. Mallet, 
F. G. s., Geological Survey of India. 
Mysorin. —The occurrence of copper in the District of Nellore, as well as in 
other adjacent parts of the country, appears to have been first brought to the 
notice of Government by Dr. Benjamin Heyne in the early part of the present 
century. In his “ Tr-acts on India,” published in 1814, an account is given of the 
rocks in the metalliferous region, and some details as to the nature of the ore. 
But the working of the mines, which appears to have been canned on extensively 
at an earlier period, was in abeyance at the time of Dr. Heyne’s explorations, so 
that he was unable to obtain any reliable information as to the mode of occurrence 
of the ore, or its quantity. He was led, however, to suppose that the amount 
^ Jour, As, Soc,, Bciigiij, 1876, p, 342. 
