OCCURRENCE OF GADOLINITE IN WEST AUSTRALIA. 289 



shows the mineral is "gadolinite" with a rather low per- 

 centage of yttrium earth, but otherwise of normal com- 

 position. 



Amongst the minerals I brought from the north-west, I 

 have two varieties of a mineral allied to " euxenite " in 

 physical characteristics, as described by Dana. One differs 

 from the other in having more manganese in the place of 

 uranium. They are essentially niobcites and titanates, 

 (with tantalum) of uranium, iron and yttrium earths, with 

 the cerium earths and thorium. They occur with cassiterite 

 and monazite in the wash dirt. I have only a few small 

 pieces, but one mineral at least was not uncommon. I 

 saw it in all the tin we bagged from different parts of the 

 country. I hope to start an analysis of one of these if 

 time permits." 



S— Dec. 3, 190*. 



