866 0. A. Reeds — JBunton Formation of Oklahoma. 



Stropheodonta becki, StrophoneVa cavumbona, Trematospira n. 

 s|>., Uncinulus 2 n. s]>., Mytilarea of. aeutirostra, Orthonychia cf. 

 plicatum, Platyceras o. sp., cf. tenuiliratum. 



Widely-ranging species. — After having listed separately 

 most of the species which occur in eacli of the four formations 

 under appropriate headings, it is well in order to make the 

 faunal list complete to give now the names and range of the 

 species which arc not characteristic of any one formation and 

 which have a stratigraphic range greater than that of a single 

 formation. In a sense they are forms which hind together the 

 faunas of the four formations. They have been arranged in tab- 

 ular form under class headings, Table II. The list shows that 

 some species which have heretofore been considered character- 

 istic of certain horizons are no longer so. This is well exem- 

 plified by Leptcenisca concava, which is restricted to a 4-fqot 

 horizon in the New Scotland of New York. In Oklahoma it 

 ranges through more than 300 feet, starting in the Henryhouse 

 (Silurian) and terminating in the Bois d'Arc (Devonian). 

 Another diagnostic fossil of the New Scotland and Linden is 

 Camarocrinus ulrichi. In the Arbuckle Mountains it has the 

 same range as Leptamisca concava. The fauna of the Upper 

 Henryhouse is prophetic of the Helderbergian, but it is still 

 Silurian since it contains a larger number of associated Niagaran 

 species. This is very interesting when it is remembered that 

 none of the Cayugan series is represented. These and other 

 points of interest will be treated in a more comprehensive 

 manner in the complete stratigraphic and paleontologic report 

 which will appear later as a U. S. Geological Survey publi- 

 cation. • 



Table of Silurian and Helderbergian formations. — When 

 the Chimneyhill, Henryhouse, Haragan, and Bois d'Arc for- 

 mations are arranged in tabular form opposite synchronous 

 formations of the completed geologic column, it is at once 

 apparent that they represent but a small part of the time from 

 the beginning of the Silurian period to the close of the Helder- 

 bergian epoch of the Devonian. That the reader may have 

 before him a graphic idea of this relation, a table of Silurian 

 and Helderbergian formations is given in Table III. Except 

 for the new terms here proposed, it has been compiled from 

 the tables given by Schuchert in his Paleogeography of North 

 America. In the various districts considered, the times of no 

 deposition as well as eroded sediments have been indicated by 

 the word " Break." 



