BAILEY, ON GREENSAND. 85 



In the ' Berlin Monats-Bericht/ for July, 1855, Ehren- 

 berg gives an account of very perfect casts of Nummnlites, 

 ft'om Bavaria and from France, showing not only chambers 

 connected by a spiral siphuncle, but also a complicated sys- 

 tem of branching vessels. He also gave at the same time 

 an account of a method he had applied for the purpose of 

 colouring certain glass-like casts of Polythalamia, which he 

 had found in white tertiary limestone fi-om Java. This 

 method consists in heating them in a solution of nitrate 

 of iron^ by means of which they can be made to assume 

 different shades of yellow and broAVTiish red, still retaining 

 sufficient transparency when mounted in balsam to show the 

 connection of the different parts. 



The interesting observations of Ehrenberg which are alluded 

 to above, have led me to examine a number of the cretaceous 

 and tertiary rocks of North America in search of Greensand 

 and other casts of Polythalamia, &c. The following results 

 were obtained : 



1st, The yellowish limestone of the cretaceous deposits of 

 New Jersey occurring with Teredo tibialis, &c., at MuUica 

 HiU, and near Mount Holly, is ^ery rich in Greensand 

 casts of Polythalamia and of the tubuliform bodies above 

 alluded to. 



2d. Cretaceous rocks from Western Texas, for which I am 

 indebted to Major AV. H. Emory, of the Mexican Boundary 

 Commission, yielded a considerable number of fine Greensand 

 and other casts of Polythalamia and Tubuli. 



3d. Limestone fi'om Selma, Alabama, gave similar results. 



4th. Eocene limestone fi'om Drayton Hall, near Charleston, 

 South Carolina, gave abundance of similar casts. 



5th. A few good Greensand casts of Polythalamia were 

 found in the residue left on dissolving a specimen of marl 

 from the Artesian Well at Charleston, S.C. ; depth 140 

 feet. 



6th. Abundance of organic casts, in Greensand, &c., of 

 Polythalamia, Tubuli, and of the cavities of Corals, were 

 found in the specimen of yellowish limestone, adhering to 

 a specimen of Scutella Lyellii from the Eocene of North 

 Carolina. 



7th. Similar casts of Polythalamia, Tubuli, and of the 

 cavities of Corals, and spines of Echinus, were found abun- 

 dantly in a whitish limestone adhering to a specimen of Ostrea 

 sellceformis from the Eocene of South CaroKna. 



The last two specimens scarcely gave any indications of the 

 presence of Greensand before they were treated with dilute 

 acid, but left an abundant deposit of it when the calcareous 



