134 



From an article in the Newburgh Telegraph, it appears that the Rev. 

 E. G. Armstrong has obtained from a locality in the town of Monroe, 

 Orange county, a crystal of pyroxene nearly eight inches in length, and 

 fifteen and a half in circumference. This is one of the largest crystals 

 of this mineral heretofore noticed. It may be remarked, however, that 

 these specimens from Orange county, although remarkable for their 

 size, want the finish which give such beauty to the crystals from some 

 other localities. 



In regard to the steatitic-pyroxene, the Rensselaerite of Dr. Emmons, 

 I have nothing further to add, except a reference to the localities cited 

 in the Report of the Geol. 2d Dist., pages 350 and 365. I believe it is 

 now generally admitted that the views presented in my Mineralogy 

 (p. 297) are correct. It is undoubtedly a mixed mineral, containing 

 steatite or serpentine in variable proportions, but usually presenting the 

 cleavages of pyroxene. It is in fact a pseudomorph on a large scale, 

 as it sometimes occurs in mountain masses. 



HORNBLENDE. 

 (Mineralogy of New- York, page 298.) 



This species is so abundant, that with the increasing attention paid 

 to our mineral resources, new localities must from time to time be dis- 

 covered. No remarkable crystalline forms, however, have come to my 

 knowledge, since the publication of the Mineralogy of New-York. 

 Some researches have been made by Dr. Blum, on the pseudomorphs 

 of hornblende and other minerals, which are worthy of being carefully 

 studied by the mineralogist. A fact mentioned by him, which particu- 

 larly interests us, is that of a greenish white augite, (pyroxene,) in the 

 Leonard collection, which he supposes to have undergone a change 

 from hornblende. This he says is indicated, both by its structure and 

 analysis. See Sill. Jour., xlviii., p. 78. 



The analysis of a variety of asbestus, (rockwood) from Staten Island, 

 gave the following results, viz : Silica, 55*20; magnesia, 30-73; oxide 

 of iron, 11*82; water, 2*25. The specimen is of the compact kind, 

 and had a greenish color, with a kind of cleavage resembling that of 

 crystalline hornblende. The above composition is very near that of a 

 specimen of rockwood from the Tyrol, analyzed by Dr. T. Thompson. 



Mountain cork and mountain leather, usually placed under horn- 

 blende, probably belong to some other species, if not themselves dis- 

 tinct. 



