4-2 Watson and J*oircll — Aye of Viryinia Piedmont Slates. 



in a steep bluff on the south side of the stream one mile west 

 of the old telegraph road (figs. 2 and 6). Figure 6 is a section 

 along Powells Creek, in which the position of the fossiliferous 

 beds is designated. 



The specimens of slate containing organic remains collected 

 from this locality were submitted to Dr. R. S. Bassler, of the 

 IT. S. National Museum, for identification, who kindly fur- 

 nished the following statement regarding them: "The slates 

 from northeastern Virginia contain numerous examples of a 

 fairly well preserved pelecypod, closely related to the Cincin- 

 natian forms of Pterinea, such as P. demissa Conrad. Asso- 

 ciated with these are very imperfect remains of what may have 

 been a linguloid shell, possibly a Pholidops or Leptol>ohts. 

 The horizon is certainly Cincinnatian and most probably mid- 

 dle Cincinnatian." 



It is a little disappointing not to have found definite evi- 

 dence of the same species in the two slate areas (Quantico and 

 Arvonia), and it is not improbable that more diligent search 

 for fossils in the Quantico belt will be rewarded. It was 

 thought at first that there was one species in common to the 

 two areas, but after an examination of the IT. S. National 

 Museum collections from Arvonia, Bassler decided that the 

 Arvonia species was not well enough defined for the most accu- 

 rate determination. Concerning the correlation of the two 

 areas on the basis of organic remains, Bassler says : "Although 

 the present collections from the slates at Arvonia and from 

 northeastern Yirginia (Quantico slate belt) show no fossils in 

 common, it appears most probable that the fossiliferous portion 

 of each is of approximately the same age, indeed that the two 

 slate belts themselves are synchronous." 



The authors made a brief visit to the same locality during 

 the past summer, but the conditions were such that no deter- 

 minable organisms different from those collected in 1909 were 

 found. 



The same fossiliferous beds were exposed in a recent open- 

 ing for pyrite near Marumsco Creek, 3 miles north of Powells 

 Creek. Fossils were likewise noted here, chiefly replaced by 

 pyrite, but the material was so disintegrated from weathering 

 that no collections preserving them could be made. 



The resemblance of the Quantico slates to the roofing slates 

 of the Arvonia district on James River was noted by Darton 

 as early as 1894,* but fossils had been found at that time only 

 in the latter district (Arvonia). The two belts are aligned in 

 the same direction of strike, similar lithologic types and asso- 

 ciations are observed, and the metamorphic and structural rela- 



*Fredericksburg Folio, No. 13, U. S. Geol. Survey, 1884. 



