Letters of Mr. Brongniart, with remarks. 219 
‘ticular thanks for your kindness in sending itto me. I have 
not only myself derived from it both pleasure and instruc- 
tion, but I have put in the power of various persons to en- 
joy it also, and they as well as myself find it very well exe- 
cuted and consequently very interesting. I was gratified to 
observe that you had been so kind as to insert the notice 
upon the manner of collecting petrifications; a notice 
which I had not myself published except for the promotion 
of my own views; still l tender you my acknowledgments. 
“ But I reserve for the end of this letter, the object that 
has interested me most, and that which has been with me a 
subject of instruction and of very varied reflections—name- 
ly, the rocks and petrifications, which you have had the 
kindness to send me and which I received in Oc} last. 
__ “Thave already made an incipient stady of them, and I 
intend to return to it when I shall be able to rere i nos ie 
means adapted to determine exactly or rather mo 
ly these fossil organized bodies. I shall confine myself then then 
for the present, to the communication of some of the reflec- 
tions, which these rocks have excited, and of some of the 
determinations which I have made respecting them; these 
determinations are made in accordance with the classifica- 
tion of mixed rocks which Ip ublished in 1813. 
“ The serpentine of New: Taven, of which you have sent 
me so beautiful a specimen, constitutes one of the ornaments 
of my cabinet and is referred with great precision to my spe- 
spies; ophicalce veinee*, (viz. veined serpentine li 7 
he rocks which accompany the meus of Wilkes- 
barre “id af Rhode-Island are, according to my classifica- 
tion, the +Phyllades pailletees ; one of ee ecenaits the 
impression of a leaf of fern, whose species soe to me a 
little different from all those of Europe which I possess. — 
organized 
bodies, which are found in your coal formations, or in those 
of anthracite, ae finally in all your bituminous formations. 
* This ts kc atuael elias 2, p. 16, wader the bea of Aeris 
Verd Antique Marble. 
+ The bah Mr. Brongniart a achists 5 with an argillaceous basis, 
eentaining mica, quartz, feldspar, amy ole, marl, &c. 
