86 



FOSSIL ESTHERLE. 



Fig. 5. 



Estheria ovata,/rom Richmond, Magnified 

 and of natural size. After Lyell. 



as the " Posidonomya minuta," may not be allied to Cypris rather than to any genus of 

 the Mollusca. 



The larger form figured by Lyell (fig. a, here copied as fig. 5 a) is stated to resemble 



Cyclas in outline ; oval and inequilateral ; ^ths inch in 

 diameter. It was from Hardin's pit, north of Blackheath, 

 near Richmond, Eastern Virginia. 



The smaller one (fig. 6 b, here copied as fig. 5 b), ^ths 

 inch in diameter, is described as being more convex than 

 ♦the other ; " resembles a young Jstarte, but may perhaps 

 be the young of the preceding." From Hardin's pit, and 

 also from Creek mines, south of Blackheath, Virginia. 



The same fossils were found at the Deep-run pits, at 



the northern extremity of the coal-field. " They occur in 



such immense numbers (at Blackheath) as to divide the shale, 



like plates of mica, into very thin lamina?. Every fresh surface exhibits a layer of them." 



In 1856 Dr. I. Lea read before the Academy of Natural Sciences of Philadelphia, 1 



some notes on the " New Red Sandstone Formation of Pennsylvania," and stated that in 



the greenish and blackish shales near Phcenixville, on the Schuyl- 

 kill, he found two forms of " Posidonia " {Estheria) both differing 

 apparently from those figured by Sir C. Lyell ; and he named 

 them the P. ovata and P. parva, " the first being about ^ths of 

 an inch in transverse diameter ; the latter more rotund, and about 

 ~ths of an inch in transverse diameter." 



Prof. E. Emmons in his ' Geolog. Report of North Carolina,' 

 1856, 2 p. 337, describes and figures two forms of Estheria as 

 Posidonia. midticostata and P. triangularis from the upper portion 

 of the Deep River series in Chatham Co., North Carolina. Ac- 

 cording to Mr. Conrad, 3 the former of these " had previously been 

 indicated by Mr. Lea under the name of P. ovata from specimens 

 obtained at Phcenixville ; and probably the latter was also indi- 

 cated under the name of P. parva from smaller specimens than 

 those presented this evening, but likewise obtained from the same 

 locality." 



The two Estheria above alluded to are figured and described 



Fig. 6. 



Estheria ovata (P. multicostata, 

 Emmons), from North Caro- 

 lina, magnified. After Em- 

 mons. 



Fig. 



/. 



Estheria ovata (P. triangularis, 

 Emmons), from North Caro- 

 lina, magnified. After Em- 

 mons. 



1 'Proceed.,' vol. viii, p. 77. 



2 In Silliman's 'Americ. Journ. Sc.,' new series, vol. xxiv, p. 42", is a notice of Emmons's 'Geo- 

 logical Report of the Midland Counties of North Carolina,' 1856, with remarks by Professor 0. Heer on 

 the Plants noticed in it. 



8 ' Proceed. Acad. Nat. Sciences Philadelphia,' for 1857, p. 150. 



