350 H. S. AVILLIAMS PALEOZOIC FAUNAS OF KASTPORT QUADRANGLE 



Six years later, in 1892,^ Dodge and Beecher published a report on the 

 "Silurian formations of North Haven," and established for them a gen- 

 eral equivalency with the Clinton and Xiagara of the Xew York series. 



In the summer of 1897 and 1898, I examined the formations of north- 

 eastern Maine (accompanied by JT. E. Gregory, who studied the petrog- 

 raphy), and from study of the fossils* established tlie presence of five 

 formations, namely, Aroostook limestone, GraptoUte shales, Sheridan 

 sandstone, Ashland shale, and Ashland limestone, as containing species 

 known in the Clinton and Xiagara of Xew York. A sixth formation, 

 the Square Lake limestone, was shown to be approximately equivalent to 

 some portion of the Helderbergian. The seventh formation, the Chap- 

 man samdstone, was show^n to have not only intimate relationship with 

 the Becrafts or Lower Oriskany fauna of the Xew York province, but 

 also to have much to connect it with the Downtonian or Tilestone for- 

 mations of Scotland and Wales. The eighth formation, the Mapleton 

 sandstone, was correlated as of Devonian age on the evidence of plants, 

 but without attempting closer discrimination of its horizon. The ninth, 

 the Moose River sandstone, in Summerset County (as had already been 

 announced by C. H. Hitchcock in 1861)^, was correlated with the Oris- 

 kany sandstone of Xew York. 



Later, 1907-1908, the Gaspe faunas were critically studied by J. M. 

 Clarke,® all of which were correlated by him as Devonian. The lowest of 

 these, the fauna of the St. Alhans beds, was shown to contain '"a congeries 

 of 51 species, of which fully one-half occurs in the Helderbergian faunas 

 (Coeymans and Xew Scotland) to the southwest," which led him to con- 

 elude that there was at the time of their deposition an open channel 

 connecting the Gaspe with the Xew York basin, in which the typical 

 Helderbergian fauna lived. 



The Arisaig (series), since the year 1868, has been recognized as hold- 

 ing faunas of Silurian age. Hall, Dawson, Honeyman, Ami, and others 

 have given tentative correlations; but lately (1909) Twenhofel and 

 Schuchert critically examined the faunas and correlated them as ranging 

 from the Clinton to a time-equivalent of the Guelph of Interior America." 

 In that paper specific relation was also recognized with transatlantic 



3 On the occurrence of Upper Silurian strata near Penobscot Bay, Maine. American 

 Journal of Science, 3d ser., vol. xliii, 1892, pp. 412-418. 



* Williams and Gregory : Contributions to tbe geology of Maine. U. S. Geological Sur- 

 vey, Bulletin No. 165, 1900. 



^ Agriculture and geology of Maine, 2d ser., 1861, p. 360. 



« N. Y. State Mus. Mem. 9, 1908, Early Devonic bistory of New York and eastern 

 North America, p. 250. 



' American Journal of Science, 4th ser., vol. xxviil. 1909, pp. 161-163. 



