146 



Levy had been led to describe the mineral as new. It was shown 

 to agree in all its chemical, external, and crystallographical char- 

 acters, with Heulandite, as found in Nova Scotia, where it offers 

 a peculiarity in its crystalline form, not before observed, excepting 

 in the Beaumontite. This peculiarity is in the near approximation 

 of the crystals to a right square prism, (supposed by Mr. Levy to 

 be the primary form,) by the undue extension of the replacements 

 on the acute lateral edges of the common crystals of Heulandite. 

 The gradual changes by which the ultimate figure is produced, 

 was beautifully exemplified in the crystals from Nova Scotia, while 

 they are not seen in the Beaumontite. The supposed Beaumontite 

 occurs with Haydenite, near Baltimore, and it has hitherto been 

 highly esteemed among mineralogists. The Lincolnite, named by 

 Prof. Hitchcock, in honor of the late Governor of Massachusetts, 

 occurs in the trap-rock of Deerfield, Mass., and in the gneiss at 

 Bellows Falls. It was shown to differ from the ordinary crystals 

 of Heulandite, only by the absence of the replacements upon the 

 obtuse solid angles of the right oblique angled prism ; a peculiarity 

 which, Mr. Alger remarked, was not confined to those crystals, as 

 others similar to them had lately been found on New York Island, 

 and at Suckasunny, New Jersey. From measurement with the 

 common goniometer, Prof. Hitchcock had found a difference of 10° 

 in the incidence of planes M on T, which led him to figure and 

 describe it as a new species. But Mr. Teschemacher, whose accu- 

 racy in the use of the reflecting goniometer is well known, has 

 measured the same crystals, at Mr. Alger's request, and found them 

 to agree precisely with the recorded angles of Heulandite. 



A copy of Mr. Alger's paper was requested for the Jour- 

 nal of the Society. 



Professor Charles Brooks was unanimously elected a 

 member of the Society. 



ADDITIONS TO THE CABINET. 



Dr. Wyman, on behalf of Mr. Brazer, presented the cranium of 

 a Lepidosteus and of a Beaver, (Castor fiber.) 



Dr. Gould, on behalf of Dr. Dodd, U. S. Navy, presented two 

 bottles containing fishes from the Grand Banks ; and in behalf of 



