Geological Equivalents. 135 
questionable cases and controverted points. Perhaps I may here- 
after occupy a few pages of this Journal with a condensed series of 
facts, in support of a general nomenclature of American geology. In 
this I intend to point out the agreement, announced to the public by 
myself, fourteen years ago, which was discoverable in almost all the 
deposits of both continents; and the few points of total disagree- 
ment—particularly the Chalk of Europe and Ferriferous rocks of 
merica. I intend to refer chiefly to organized remains; the study 
of which, I believe I happened to be the first to paradocs, into an 
American geological school, in the year 1818.* 
ars ago,) ata tow labelled by Le Sueur. By these means we could understand 
wach other, et own school; while we waited, pags for competent author- 
are rarely present. <A recent specimen me the Albany museum, par among the 
Tubbish of the New Haven museum, formerly kept by Mix, (probably from the 
West Indies,) is the only one, whether a relic or recent, ever seen in America, as far 
I which contains those cliaracters. I have, I believe, two undescribed 
a Lichen, to which I A ee temporary names also. I will give the old 
names (if named) as soon as I am ‘ 
F Excnrn Us ~neneraangoeses s perforates strata transversely; rings 
ound in the lowest and compact layer of metalliferous eee —called Siotatl 
Tock by Conybeare, and bird’s- -eye marble by stone-cutter: 
leyelus. ategy of low rings alternating with shigié high ones. Found in 
sraywa 
E. giganteus, a mee and of great length. Found in saliferous rocks. 
wise ‘erruptus 8.—High rings interrupted by single and double low ones. Found 
Tag. 
second 
— i idly, ri ite. Found 
in coral ra 5 -—Tapering rapidly, rings even, generally pale or white 
us.—Rings distinct, with their edges ae ; always curved, and lying 
; 's. Found in shell limestone, at Glenn’s Falls. 
E muscioides.—Stipes cespitose, sub- pitted: fistulous, bearing leaves 
Sometimes arranged spirally, or densely scattered on all sides. Found 
n layers, in and under shell marl. 
i ti ER trilobioides. —Length and breadth nearly equal; side lobes one sixth 
rea of the middle lobe ; ; joints four, posterior one broadest and cleft on the 
ieee resemblance to to the trilobites. A carbonate of lime erering is very satire 
bles eo The ineurved tail of Brongniart’s Cancer punctulatus resem 
“Tustag “trifaction. Probably all the animal was very perishable, but the thick 
“ous tail; which is all that now. remains. 
