82 CRETACEOUS GROUP 
From the calcareous strata of New Jersey, where it is 
of frequent occurrence. 
This shell has a strong resemblance to Planorbis ; and 
Mr. Sowerby mentions that he found shells of a similar 
character in the English Green sand, (Min. Coch. Bp: oo,” 
92.) The American shell appears to belong to the ge- 
nus Vermetus as revised by Mr. Sowerby. 
TELLINA. 
Finely preserved casts of a delicate Tellina, upwards 
of an inch in length, occur in the arenaceous beds of New 
Jersey. 
LUNULITES. 
Casts of a Lunulite, about a fourth of an inch in dia- 
meter, have been observed with the preceding fossil. 
It will be observed that I have used the genus 4mmo- 
nites in its unrestricted acceptation: the A. Delawaren- 
sis and A. vespertinus are true Ammonites, while all the 
other species of this synopsis might be associated with the 
genus Orbitulites of Lamarck. 

