Marl of New Jersey. 91 
to a similar group observed in the south of France, by M. Dufresnoy, 
Mining Engineer. This Report has been published in the XXII 
volume of the Annales des Sciences Naturelles ; and I have therein 
mentioned your important observations, at the same time availing my- 
self of them, to support the principles I some time since advanced 
in my work on the Importance of Zoological characters in Geology. 
** You will perceive that I have not hesitated to admit, with M. 
Dufresnoy, that the formations he has described, belong to the Cre- 
taceous group, although they contain some organic remains, character- 
istic of tertiary beds: (terrains thalassiques.) In like manner, while 
the deposits which you have referred to the chalk series, contain 
some fossils which occur also in other formations, we cannot for this 
reason refer them to any other than the chalk, because the charac- 
teristic reliquie of the latter predominate so much, as at once to de- 
termine the epoch to which they belong: for, excepting a few tere- 
bratule, &c., I can only recognize these fossils in secondary beds, 
and more specifically in those which 1 have designated by the name 
of Pelagic. 
“The fossils you describe are not only characteristic of the creta- 
ceous group, but are found neither abundantly nor constantly in any 
other: they belong to the entire extent of the series; nor am I cer- 
tain that they are more indicative of the lower chalk (la glauconie 
crayeuse et la craie tufau) than of the upper or white chalk. 
*¢ With respect to amber (succinite, Br.) and lignite, they are rare- 
ly observed in the chalk mass, but are mostly found above it in the 
plastic clay, or below it in the marls of the green or ferruginous sand: 
but these substances are of too little importance’ to affect a position 
established by other characters.” 
M. Brongniart further explains his views of the chalk formation, 
in the Report on M. Dufresnoy’s memoir, above alluded to, from 
which I shall beg leave to offer two or three extracts; merely pre- 
mising that the Report is signed by Messrs. Beudant and Brongniart, 
but is from the pen of the last named gentleman. 
Extracts from the Report on the Memoir of M. Dufresnoy, &c.— 
Read before the Fr ench Institute, April 25, 1831. 
‘‘ Every one thinks he knows what chalk is: the inhabitants of Paris, 
and of the north of France, who are surrounded by chalk hills, who 
see this mineral employed for numerous domestic purposes, and in 
the arts, always figure to themselves a soft stone remarkable for its 
