Jttne, 1841.] 33 



Polyparia 



Astrea. 



Astrea Marylandica. Incrusting, very thin ; cells, unequal, sub- 

 pentagonal, margin acute and prominent ; radiating lamellae dis- 

 tant, about 12 in number. 



Frequently incrusting the Pecten Madisonius on James river, 

 Virginia. 



A. bella Incrusting, thick ; cells unequal ; pentagonal, rays nu- 

 merous, minutely and beautifully denticulated ; frequently alter- 

 nated in length. Near Newbern, N. C. 



Lower Tertiary Fossils. 



Cardium. 



Cardium Nicolletti. Cordate, ventricose, polished, with crowded 

 minute, impressed radiating lines ; beaks central ; summits very 

 prominent ; posterior margin nearly direct, slightly emarginate ; 

 posterior slope with larger striae than the disk, and muricated 

 with radiating rows of approximate, rather obtuse, slender and 

 prominent tubercles. Length 2 1-2 inches. Height the same. 

 For this splendid Cardium, I am indebted to my distinguished 

 friend J. N. Nicollet. It was found in green clay at 50 feet in 

 height on the right bank of the Washita river, Monroe county, 

 Louisiana. 



Fusus. 



Fusus pachyleurus. Fusiform, thick, with spiral striae not very 

 distinct ; whirls of the spine concave above, convex, and with 

 obtuse ribs below, except upon the lower whirl which is entire ; 

 body whirl also destitute of ribs, abruptly rounded or subangu- 

 lated at base, ventricose ; beak long, thick, straight ; labium 

 widely reflected; channel contracted. Length 2 1-2 inches. 



Presented by Mr. Nicollet : it is from the Lower Tertiary of 

 Alabama. 



Professor Johnson made some remarks on the magnetic 

 phenomena attending the congealing of cast-iron. 

 6 



