344 The Upper Devonian Deposits of Maryland 



The rock formations composing the Portage beds in the above table 

 were also described by Dr. Clarke in another memoir published earlier in 

 April than the one just quoted in which he stated that " Throughout this 

 interval of about 600 feet tlie Naples fauna prevails, without evidence of 

 encroachment of tlie eastern or Ithaca fauna." ' 



The following year in the description of the geology of the Watkins and 

 Elmira quadrangles Dr. Clarke transferred the High Point sandstone 

 from the Chautauquan to the Senecan, while the Chautauquan began with 

 the Prattsburg shale succeeding which is the Chemung sandstone and 

 shale." Spirifer disjunctus Sowerby occurs in the list of fossils from 

 the Chemung sandstones ; ° Hall's original description of the " Chemung 

 group " is quoted, following which Dr. Clarke stated that " It will be seen 

 that the definition of this formation is derived from tlie very region we 

 have here under consideration and embraces those rocks to wliich we 

 are now applying the term in the original and restricted meaning." ' The 

 above classification has recently been reviewed by Prof. H. S. Williams 

 who wrote that " x\ccording to the list of species reported by them 

 [Clarke and Luther] for the Watkins and Elmira quadrangles their West 

 Hill flags and shales and High Point sandstone should both be included 

 in the Chemung formation as here defined [in the Watkins-Catatonk 

 folio]." = 



The above rather extended review of the use of the names Portage and 

 Naples in their typical sections in western New York is given in order 

 that the reader interested in stratigraphical geology may readily acquaint 

 himself with the historical usage of the names which appear very fre- 

 quently in this monograph in the description of the Upper Devonian 

 rocks and fossils of Maryland. 



Again, east of the Naples section in the Ithaca region the Portage 

 stage is represented by the Sherburne sandstone and Ithaca beds and 

 the writer in 1903 proposed that these two members be united and 



' N. Y. State Museum, Mem. 6, p. 213. 



= N. Y. State Mus., Bull. 81, p. 4. 



^ Loc. eit., p. 24. 



* Loc. cit., p. 23. 



=>Geol. Atlas U. S., Folio 169, Field Edition. 1909, p. 85. 



