88 PKOCEEDINGS OF THE NATIONAL MUSEUM vol.76 



liigh in the Ordovician — perhaps within the broader zone of the 

 American Viohi limestone., though the Trinucleidae in the two are 

 quite different. The half dozen species in the latter are of Grypto- 

 lithus^ whereas those in the Swedish formation are of Tretaspis. 

 One of the latter is identified with T. hucklandi^ a Drummuck species 

 in Scotland, which according to preceding argument (pp. Gl-69) is 

 early Silurian rather than late Ordovician. But the Viola also is 

 not firmly fixed in the position given it on the chart. We know only 

 that it is younger than Trenton and in unconformable contact with 

 the Fernvale above. It may therefore correspond to the whole or to 

 some part of the Cincinnatian, or, if it does not belong between 

 the Eden and the Maysville, its place may be in the hiatus between 

 the Maysville and the base of the Kichmond. The fauna gives no 

 conclusive indication whatever, and what evidence it does present 

 seems to favor the last interpretation rather than the others. If 

 the Trinucleus zone proves older than the Viola the position of the 

 underlying Chasrnops will also be lowered in the scale. 



Etage 3" {Orthoceras limestone) probably is older than given on 

 the chart. A positive statement is not yet warranted, but judging 

 from its fossils I am inclined to believe that eventually Etage 3 ' 

 and the Kunda of the Baltic Province will be found to correspond to 

 our Buffalo River series. 



Baltic region. — Above the Wesenberg no material change has been 

 made from the correlations indicated in the table published in my 

 1926 paper on the Ordovician-Silurian boundary. The Borkholm is 

 again correlated with the Leptaena limestone of Sweden and the 

 Keisley of England, and all three are placed in the general horizon 

 of the Upper Medinan. The Lyckliolm, also, is referred as before to 

 the Richmond. More doubt is entertained regarding the position of 

 the Wesenberg and also as to the stratigraphic relations of the Kegel 

 and the four members of the Wierland group of Raymond to Or- 

 dovician formations of America. A somewhat lower position is 

 suggested for the latter than in the preceding paper; but I am not 

 certain that the present arrangement is nearer the truth than the 

 other. On the other hand, I can not free my mind of the suspicion 

 that most if not all of these east Baltic formations were not deposited 

 at strictly the same times as those in either of the Scandinavian 

 countries or those in England, Scotland, and Ireland or those in 

 North American areas, with which they have hitherto been more or 

 less confidently correlated by others as well as by me. 



