Miscellaneous JVotices in Mineralogy, Geology, ^c. 241 



It is, as we are informed, so abundant in some places, that 

 the people use it in dying, without resorting to any other 

 supply. We are not aware that this source of alum has 

 been observed in other countries. We have not room to 

 discuss the origin of the alum in these cases ; but we will 

 add, that in some decomposed mica slates, we have seen 

 sulphur in a state of freedom, mixed with the proper con- 

 stituents of the rock, and burning abundantly with the char- 

 acteristic flame and smell when thrown on the fire. Indeed, 

 is it not probable that alum will be obtained from more 

 rocks and minerals than have yet been thought of for this 

 purpose. The very remarkable example of Breccia from, 

 Mount D'Or in Auvergne in France, mentioned in volume 

 two page 356 is an example in point. 



21. Remarkable locality of Garnet. 



Garnet is a mineral of such frequent occurrence in primi- 

 dve countries, that it would be useless to attempt to point out 

 all its localities. In Connecticut it is most abundantly dif- 

 fused through the vast strata of mica slate and gneiss, but 

 especially of the former. The garnets mentioned in the 

 following account are remarkable for the neatness of their 

 crystahzation — the planes are smooth, the angles, and edg- 

 es well defined and they are bounded, each by twenty-four 

 trapezoidal faces; not unfrequently they occur in pairs; 

 their general size is from that of grape shot to that of mus- 

 ket and pistol balls ; they are imbedded in a mica slate, 

 composed almost entirely of Mica which is in plates and 

 possessed of so little cohesion, that both on the outside and 

 inside of the rock, it crumbles easily between the fingers. 



22. Garnet Rock. 



Ewtract of a letter from Mr. Lloyd Seeley, to the Editor, 

 dated Weston, Ct. May 27, 1820. 



" Garnet Rock or the precipice in and about which, gar^ 

 nets are found in abundance and perfection, is situated one 

 mile and an half South of the Congregational meeting-house 

 in the town of Reading, and about one half mile North-west 

 of the junction of the two largest branches of the Saugatack 



¥©L. I.n....No. 2. ^ 31 



