L. Lesquereux on the Coal Formations of the United States. 198 
Arr. XXTII.—0On some questions concerning the Coal Formations 
of North America, (Continued from p. 25 of this vol.) 
By Leo Lesquerevx. 
Families, Genera and Species of Fossil Coal Plants in the United States. 
This general examination is made for a two-fold purpose, 
ins of fossil plants found in our Amer- 
First; to see how the remai ! 
ican coal-measures agree in characters with those of Europe: 
gr : . 
or rather to find if these remains of ours cannot give some farther 
light concerning species, genera and families 0 coal plants, al- 
* The orthoscopic eye-piece of Grunow consists of an eye lens partially achro- 
Matized in giantineaiae with a field lens differing in form from the ordinary Huy- 
ghenian.—o. n. pr. . 
After this article was in print, I received from a friend a paper of femaie 
Mi. Eaton, Esq. (Proceedings B'S. N. H.,, vol, viii, p. 105.) Mr, Eaton has dev 
himself with success to the production of ambrotypes of microscopic objects. 
Troy, N. ¥., July 23d, 1861. 0. NR. 
Am. Jour. Scr.—Szconp Srnms, You. XXXII, No. 95.—Serr., 1861. 
25 
