Mineralogy and Geology. 267 
3. Chiolite, anew mineral from Miask; by Fr. v. Wortu, (Ver- 
n 
mineral resembling cryolite. It occurs granular, with a shining lustre, 
and presenting a grayish, yellowish, or snow white color. The streak 
Specific gravity of the masses 2°6209 ; of the powder 2°770. The struc- 
ture of the massive pieces is imperfectly foliated, and the surface of 
foliation exhibits a lustre between greasy and vitreous. ‘The specimen 
examined by M. Worth, indicated that it was associated with lithia 
mica, massive fluor spar, and quartz. It melts easily in the flame of a 
candle, but at first decrepitates. Its transparency increases in water. 
According to the chemical analysis of A. new, it consists of 
aluminium 16°48, sodium 25°72, potassium 0:58, magnesium 0-76, yttri- 
um 1-04, fluorine 56-00 100°38, giving the formula 2Na Fl+ Al Fl,. 
Cryolite differs in containing, for the first term, 3Na Fl, and also in its 
higher specific gravity. The name chiolite is from the Greek word for 
snow. 
4. On the alleged Coéwxistence of Man and the Megatherium; by C. 
Lyett, (addressed as a letter to the Editor of the Times, and publish- 
ed in the Times of Dec. 8, 1846.)—Sir: A considerable sensation ap- 
pears to have been caused in the minds of the scientific, and part of 
the unscientific public, by the announcement in many of the newspapers 
of the discovery in America of a fossil human bone associated with 
1846,) a brief notice of the reported discovery, copied from an Amer- 
ican paper, and which the editor has inserted with a judicious caution 
roid animals. I visited Natchez in March last, on which occasion | 
was informed of the antiquity assigned to the human relic, and having 
examined carefully into the evidence, came to the conclusion that the 
proofs of the coéxistence of the human individual: with the megathe- 
_In order to explain its position, a few words on the geology er 
gion will be indispensable. . The broad, flat, alluvial plain of = ar ed 
fon will two hundr 
