PLATE 5(bi»). 



Fig. 1. 46. 3. Maclurea magna. (Pag. 26.) 



1 a. An obliquely vertical section of the fossil, passing nearly through the centre of the spire above, but more 



on one side below, so as to escape the umbilicus. 

 1 b. A vertical section of the outer volution : a common appearance upon the weathered surface of the rock 



at Chazy. 

 1 c. An unusually large specimen of the same species ; the surface worn so as to obliterate the striie, and 



obscure the first volutions. 



