1889. | NEW YORK ACADEMY OF SCIENCES. 185 
. May 27, 1889. 
STaTED MEETING. 
~ The President, Dr. NEWBERRY, in the chair. 
Thirty-eight persons present. 
Mr. Witi1aAmM E. HIDDEN remarked upon the recent discov- 
ery of gadolinite and other yttrium ores in Llano County, Texas, 
and upon the great promise of that region for yielding commercial 
quantities of the so-called ‘‘rare earths.” He noted the occur- 
rences, as identified by himself, of fergusonite, allanite, cyrtolite, 
uraninite,and fluorite, at this Texas locality. He also announced, 
as a preliminary notice, that he had, in conjunction with Mr. J. 
B. MAcKINTOSH, identified a new thorium mineral among the 
first lot of Texas specimens received. It conformed to a thori- 
um silico-uranate, in which half the bases were uranates and half 
silicates. Forty-one per cent of thoria and 22 percent uranic ox- 
ide were found, and a complete analysis is promised later. The 
mineral has a density of 4.43-4.54, and is tetragonal in form. 
Its color is yellowish brown. With it occurs a variety of urani- 
nite having sp. grav.=8.01, and containing a notable per cent 
of the yttria-ceria group of earths, which were thrown down by 
ammonium oxalate. It may also contain thoria. If this shall 
prove to be a true species, he suggested for it, provisionally, the 
name of Chilorothorite. 
The locality has been thoroughly prospected since the begin- 
ning of the year, and work is now going on there in an endeavor 
to find marketable quantities of these rare minerals. Up to this 
time, the region has yielded about 500 pounds of gadolinite 
alone. One group of two crystals weighed 42 pounds,—an un- 
precedented size for the species. Mr. HippEN said that he 
hoped soon to be able to supply a hundred pounds of yttria de- 
rived from minerals of this locality. 
A full paper, with analyses of all the minerals of the district, 
will soon be completed and made public by Mr. J. B. MAckIN- 
TosH and Mr. HippEN, jointly. 4 
Dr. ALBERT R. Lepovux then read the following communica- 
tion: 
