Beaumontite and Lincolnite identical with Heulandite. 235 



This is the only respect in which the Heulandite from Nova 

 Scotia, and M. Levy's mineral, differ from each other ; and it is 

 in reference to this single peculiarity in the approximation of the 

 crystals of the Nova Scotia mineral to a right square prism, that 

 it has hitherto commanded an especial interest among our miner- 

 alogists. I had never seen the decrement carried so completely 

 out in the crystals from any other locality, until these beautiful 

 specimens met my eye from Baltimore. The smaller replace- 

 ments b b', which are often seen in the crystals of this mineral 

 from Faroe, I have never observed among the specimens from 

 either of the localities here referred to, nor from any locality in 

 the United States.* 



To remove all doubt as to the identity of the two minerals, I 

 requested Mr. J. E. Teschemacher to separate some of the best 

 crystals from my Baltimore specimens, and subject them to meas- 

 urement by the reflecting goniometer, as I well knew the public 

 would have the fullest confidence in his use of that instrument. 

 He has informed me that P on P gives 90°, M on T 130°, M on a 

 143° 17', P on a 111° 58', and adds that he has no doubt the 

 mineral is Heulandite. The variation in the third measurement 

 was owing to the imperfection of the surface. We have, there- 

 fore, every reason for believing that the specific nature of the 

 Beaumontite of M. Levy, can no longer be maintained. It is 

 proper to add, that the same name, in honor of a distinguished 

 French naturalist, Elie de Beaumont, had already been applied 

 to another mineral from Chessy in France, described and analyzed 

 by my friend Dr. Charles T. Jackson.f 



Lincolnite. — Prof. Hitchcock in his Final Report on the Geolo- 

 gical Survey of Massachusetts, (p. 662,) has given the descrip- 

 tion of a mineral found in the vicinity of Deerfield, which he has 

 named in honor of the late governor of that state. Unfortunately, 

 it must share the same fate with Beaumontite, though it seems less 

 entitled to the distinction of a new species ; for in every respect 

 but one, viz. its not being replaced on the obtuse solid angles by 

 the planes a, as shown in fig. 1, it is impossible to discover any 

 dissimilarity between this mineral and Heulandite ; both exhibit- 

 ing the same characters before the blowpipe, the same color, lus- 

 tre, hardness, &c. The crystals of Lincolnite are very small, 



* See fig. 2 in Phillips' Mineralogy, Allan's edition, p. 25. 

 t American Journal of Science, Vol. xxxvn, p. 398. 



