kaymoxd: correl.\tiox of the ordoviciax strata. 235 



Stose from thin-bedded dark limestone at the Mattheson limestone 

 quarry near Abingdon, Virginia, I found numerous specimens of a 

 Robergia very like R. micropthahna and a Telephus like T. bicuspis. 

 These trilobites were associated ^^^\t]^ diplograptid graptolites which 

 Dr. Ulrich assures me are of typical Xormanskill species. Such an 

 association is found in the Climacograptiis pidiUiis zone of the Lower 

 Dicellograptus shale at Anderson, Jemtland, Sweden, and the asso- 

 ciation is too remarkable a coincidence to indicate anything other 

 than approximate contemporaneity of the two formations. Stose 

 gives the following section at Abingdon. 



Se\aer shale — Eden fossils in upper and Trenton fossils in Feet, 

 lower part. 800 



ISIoccasin limestone. Red limestone with few fossils. 400 



Ottosee limestone, with Echinosphaerites. 200 



Athens shale. Calcareous shale and dark blue shaly lime- 

 stone above; dark gray fissile shale below. 

 The fauna mentioned was found in lower 

 part. 500-600 



Stones River limestone. 400 



Knox dolomite (of Beekmantown age). 



From this section it ma\' be seen that the Xormanskill is vounger 

 than some part of the Stones River, and considerably older than the 

 Sevier shale, the lower part of which seems to be of Trenton age, 

 though to what part of the Trenton it appertains is not yet evident. 



The other section containing the Xormanskill faima was described 

 by Powell (105) and is near Salem, Virginia. He records the following, 

 in descending order : — 



Medina sandstone (Silurian). Feet. 



8. Shale, very fossiliferous. X'o list of fossils. 1200 



7. Blue to black shale and limestone. • 300 



6. Red and gray sandstone without fossils. 400 



5. Blue and black limestone without fossils. 500 

 4. Black carbonaceous shale with numerous graptolites. 32 

 species are listed, including Xcmcujraptus gracilis, Clima- 

 cograptus pidiUus and Dicellograptus sextans. Triarthrus 



and Trinucleus are also recorded. 560 



3. Coarse grained dark limestone with bands of marble. 250 

 2. Pure "dove" colored limestone with a Tetradium and 



large gastropods. 50 



1. Cherty magnesian limestone with Maclurites. 500 



