; 
Review of Dana’s Mineralogy. - 383 
year, suggests the union of Sillimanite, Kyanite,* and Andalusite, 
" under the general formula Al*Si*. There are strong reasons 
for believing that silicate of alumina is a dimorphous substance, 
and on this supposition we may consider Sillimanite one of its 
forms. Mineralogically Sillimanite is certainly distinct. 
Tourre.—We have the following analyses of Iolite from Had- 
dam, Ct. and Unity, in New Hampshire, by Dr. Jackson. (p. 406.) 
addam. Unity, N. H. 
Silica, . : ‘ é . 48°35 48:15 
Alumina, : é ‘ ‘ 32°50 32:50 
Magnesia, : . 5 ‘ 10-00 10°14 
Protoxyd of iron, . ‘ , 6:00 7:92 
Prot. manganese, . é ‘ 0°10 0:28 
Water, . * , . 3°10 0-50 
100-05 99-49 
ILMENITE.—‘ The Washingtonite of Shepard, a variety of Ilmenite, 
has been analyzed by J. S. Kendall in Dr. C. T. Jackson’s laboratory, 
and found to contain titanic acid 25°28, peroxyd of iron 51°84, pro- 
toxyd of iron 22°86—99-98. It appears therefore to be nearly identi- 
cal in composition with the hystatic iron ore of Breithaupt, or the Hys- 
tatite variety of this species.”’ (p. 527.) 
If we were to form our estimate of the progress of American 
mineralogy by taking into view the number of exploded species 
of American minerals only, we should be forced to conclude that 
such progress was of rather an equivocal nature. But we must 
bear in mind that the science is burthened with hundreds of 
synonyms of European minerals which still hold a place in the 
index of the present work, while too many of the bad American 
Species have been proposed by foreign authors. ‘There can be 
no objection to giving the following alphabetical list of Ameri- 
can species which have been proposed and subsequently aban- 
doned. The list is made out from our own opinions, and it is too 
much to expect that it will meet in all cases the views of authors. 
x Sa Kyanite from Chesterfield in Massachusetts, has been recently analyzed 
by one of my pupils, (Mr. C. H. Rockwell of Norwich.) The specimen was 
finely crystallized, se and azure ae it yielde 
ilica = 
42:74 
‘ ‘ 
Alumina, - oe . : : 57-90 
om : z : i : trace. 
100-64 
This analysis adds farther confirmation to the views expressed in the text.— 
B. 8., Jr. e e 
