44: Watson and Powell — Age of Virginia Piedmont Slates. 



Doctor R. S. Bassler furnishes the following statement of 

 the fossils from the slates at Arvonia in the collections of the 

 U. S. National Museum : "The collections of the U. S. National 

 Museum contain twelve species of fossils from the slates at 

 Arvonia, Buckingham County, Virginia. These are from the 

 same horizon as the crinoid remains which resulted in Dr. Wal- 

 cott referring the strata to either the Trenton or Hudson (Cin- 

 cinnatian). The additional species make up an assemblage of 

 forms which seems to he of middle Cincinnatian age. Most of 

 the fossils are so distorted that their specific identification is 

 necessarily uncertain. Many of the Rajinesquinas, for exam- 

 ple, have a diameter of six inches, although the original shells 

 were undoubtedly not more than two inches wide. The three 

 species of echinoderms are numerously represented, a fact 

 which is most unusual for Ordovician faunas. Indeed, if this 

 fauna could be found well preserved, the general association of 

 species would probably be very different from that of any Ordo- 

 vician strata west of the Blue Ridge." The list follows : 



VJyclocystoides sp. (one-third to one-half inch in 



\. diameter and with twelve to fourteen plates). 

 ■^Protaster? sp. 



Ijtli/ptocriniis cfr. decadactylus. ■ 



Valymene callicephala. 



Trail resembling Asaphoidic/mus. 

 \Mafinesquina alternata (cfr. var. ponderosa). 

 ^^lectorthis cfr. plicatella. 



Tsotelus cfr. gigas. 



Tentaculites sp. 



JBnthvtrephis cfr. gracilis. 



Buthotrephis cfr. succidens. 



An indeterminable ramose bryozoan. 



Five drawings of crinoids from these slates are reproduced 

 by Darton in the paper published in 1892.* 



There are several specimens of a trilobite Calymene callice- 

 phala (Green) and an indeterminable crinoid, probably Protas- 

 ter n. sp., in the collections of the University of Virginia, made 

 by the senior author from the slates at Arvonia. 



Brooks Museum, University of Virginia, October 18, 1910. 

 *This Journal, vol. xliv, p. 51. 



