Notice of Topaz and Phenakite. 329 
Such, gentlemen, is a rude outline of the great revolutions of 
terrestrial vegetation, as the researches made upon this subject, 
within the last thirty years, have enabled us to trace them. Each 
day will doubtless add new traits to these details; but recent 
discoveries, by confirming the results at which we had previ- 
ously arrived, seem to assure us that this general delineation will 
not experience great changes when, thanks to the materials that 
are being collected on all sides for this object, we shall be ena- 
bled to srenetosti this rough draught into a picture more 
and complete. 
Arr. Vil.—WNotice of a second locality of Topaz in Connecticut, 
and of the Phenakite in Massachusetts ; by Cuartes UpHam 
Sueparn, M. D., Professor of Chemistry in the Medical College 
of the State of South Carolina. 
Amone specimens which I Stained at the China-stone quarry in 
Middletown two years since, I find one to be invested with above 
fifty crystals of Topaz. They measure from $ to $ of an inch 
in length, are very slender, and perfectly transparent, being at- 
tached by a lateral plane to crystals of albite. Owing to their 
minuteness, it is difficult to distinguish, except in one or two in- 
stances, the leading planes of the forms. In one crystal, I detect 
the truncation of the obtuse lateral edges, the truncation and 
bevelment of the acute lateral edges, and the replacement of the 
acute solid angles by faces inclining to the last mentioned trun- 
eating planes under angles of about 153°. In addition to which 
modifications of the primary form, there are also visible the re- 
_ placement of the terminal edges by two planes and that of the 
edges intermediate between these and the angular truncations, by 
single planes. The future exploration of the quarry will probably 
lead to the discovery of more perfect crystals of the present spe- 
cies than have hitherto been found in the United States. 
The Phenakite, it will be recollected, was first recognized as a 
distinct species by NorpeNskroLp, in 1833,—the specimens having 
been derived from the vicinity of Katherinenberg, upon the east- 
ern slope of the Ural mountains, where it occurs in granitic rock 
along with emerald and mica. The resemblance of the mineral . 
is said to be a =e to quartz; like that species, it being de- 
Vou. XXXIV.—No. 2. A2 
