Sand Formation of the United States. 293 
qu’ils sont percés de trous de Tarets, (‘T'eredo) qui ont remplis: pos- 
terieurement par de la pyrite.”, The last two circumstances are 
common to our own lignites. 
Humboldt, in his Tableau des Formations Geologiques, gives as a 
synonym of the ferruginous sand series, Grés secondaire a Lignites, 
in contradistinction to his Grés tertiaire a meres or Plastic Clay 
formation. 
Cuvier* describes the green sands of France as senile both 
lignite and amber : the former is abundant in the’green sand between 
Dives'and Fecamp. The iron sand of. England, say Phillips and 
Conybeare,t contains a considerable quantity of fossil wood ;. while 
in the neighborhood of Folkstone and Cambridge, the — _= 
retains the woody fibre. 
I will adduce but one other instance—that of the kenito ne in 
the green sand in the Isle d’Aix, near La Rochelle. At this place 
is@ submarine forest of dicotyledonous trees, sometimes* bituminous 
and brittle, and again having the texture of jet... These tieiten are 
perforated by the Teredo, and accompanied by amber.f «> 
- ‘Ehave detailed these facts to shew (what some have. doubted) that 
the: vast deposits of lignite with amber, lately exposed in the Dela- 
ware and Chesapeake canal, do not offer insurmountable. objections 
to the position I have taken—that the beds in which peereions 
occur are secondary. 
. Tam aware, however, that some = athe geologists, iideseie 
on the superposition of strata than on their organic products, have re- 
ferred all those formations I have just quoted, to the- tertiary elass, 
including therein the whole chalk formation. _ But I am disposed in 
this case to adopt the opinion of Humboldt, ‘who is known to:con- 
sider fossil remains merely as collateral aids in deciding the-relative 
Position of strata. ‘“ Malgré les analogies que présentent les” gres a 
lignites (sables verts et argiles plastiques) au-dessous. et au-dessus 
la Craie, cette formation pourtant appartient plutot au terrain se- 
condaire qu’au terrain tertiaire, fnqual plusicurs Biopeomnt ee 
le rapportent.”|} nae 
It is almost certain, salir: pas ka real plastic dopdiumtiet 
does occupy a considerable tract in New Jersey, Maryland ew dn 
a letter recently addressed to me by. Prof. Eaton, is the 
* Dise. sur les meats p- 294. 1 Geol. p. 137, ones 
t Humboldt’s Gissement des si P- — ae re 
_ |} Gissement des sissies 
