TO GEOLOGY. 193 
FAMILY LAMELLIFER/A. 
GENUS TURBINOLIA. (Lamarck.) 
T. Maclurii.* Plate 6. Fig. 206. 
Description. Turbinolia cuneate, minutely granulate, 
without ribs or furrows, swollen, furnished with two longi- 
tudinal tubercles on each side, on the superior part ; base 
rounded ; star subelliptical; pores very minute and irregu- 
larly interspersed among the granule ; lamelle granulate. 
Diam. .6, Length .8, Breadth .9, of an inch. 
The segment is a magnified view. 
Observations. This very curious species differs in its 
exterior characters from any other I am acquainted with. 
It has no longitudinal strie, which all the other known 
species have. No other described species has longitudinal 
tubercles like this. The granule are very small and 
sometimes form together. In several specimens four to 
eight smaller tubercles, or rather ribs, as they are elon- 
gated, may be observed on each side, but these are not 
specifically different. The superior part appears to be 
very fragile, there not being among a great number a 
single one entirely perfect in that part. 
* Named after the distinguished geologist, William M’Clure, Presi- 
dent of the Academy of Natural Sciences of Philadelphia. 
Z 
