gee Ae 
ae’ 
216 M. Alew. Brongniart sur les caracteres Zoologiques, &e. 
After these general considerations M. B. proceeds to 
the consideration of several anomalous members of the 
chalk formation; all o —_ he refers to this formation 
—- the analogy of their fossi 
1. Chalk of Rouen, Havre, cid Stonfleur. At the mill 
f St. Catharine, near uen, the white chalk is found 
overlying the chalk tufa or green sand. The two latter 
contain many fossils not found in the former. At Havre 
and Stonfleur, the white chalk is wanting. The inferior 
chalk is there exactly analogous to that at Beachy Head, 
and Dover, Eng. and at menenties W. of Calais; it is sepa- 
rated at the two last places from the white chalk or tufa, 
there present, by a bed of blue All these locali- 
ties of green sand and tufa are Wieitterined by precisely 
similar fossils, of which M. B. gives a catalogue 
. Chalk of oe ca Ns gelladesermsne Bayonn 
“The chalk © - of France terminates at the S. line — 
fete but its siralificationis is fase by beds of Flack 
hornstone, which divide it into numerous layers. _ It 
abounds in shells, some of them (ostrea vesicularis,) like 
the smaller specimens of Meudon. 
_ Passing south west, other rocks occur referable to the 
chalk foraation where it was not before suspected. Such 
is the hard gray sandy micaceous limestone, which forms 
he er of the soil around Bayonne, and particularly the 
cks of Biarite. It contains shells analogous to those 
of the chalk tufa near Paris, particularly the spatargus ob- 
natus. Its stratification can be ascertained only by | 
difference in the solidity of its parts. It is made up of 
alternate zones of a grayish, crumbling, nt aan oa 
sony a anda hard limestone, divided into a sé 
of irregular nodules, projecting from the esca 
the flints in white chalk. it abaewies in fragmenta. of thells 
particularly echinites, but no ammonites. Although mapy 
of these shells have specilic differences, yet their general 
character is that of the chalk formation 
__ 3. Chalk of Poland, from these localities—white chalk 
Tike that of Meudon, with black flints and. belemnites, 
