Reviews — Lower Devonian Fauna, United States. 179 



Y. — A Lower Devonian Fauna of the United States. 



The Fauna of the Chapman Sandstone of Maine, including 

 Descriptions of some Related Species from the Moose River 

 Sandstone. By Henry Shaler Williams, assisted by Carpel 

 Leventhal Breger. Professional Paper 89, Department of the 

 Interior, United States Geological Survey (George Otis Smith, 

 Director), pp. 347, with 27 plates. 1916. 



rPHE principal author of this monograph, Professor H. S. Williams, 

 JL has for long been an authority on the Palaeozoic rocks and fossils 

 of Maine, in the endeavour to trace a relationship between the 

 well-known Upper Palaeozoic of Europe and that of the interior of 

 the North American Continent. In the volume before us we are 

 introduced to an extensive fauna belonging to the Chapman Sandstone 

 formation of Maine, which is regarded as possessing an intermediate 

 facies and so " linking together the faunas of New York and those 

 of the Tilestone, or terminal Silurian, of Great Britain ". In the 

 study of British collections it was found that hardly any of the species 

 were actually identical with those of the Chapman fauna, although 

 many showed marked affinities. For purposes of comparison, the 

 closely related fauna of the Moose River Sandstone exposed in Central 

 and Northern Maine is also considered, but not exhaustively, only 

 a few new species being now described. Some further forms from 

 typical regions of Aroostook County, Maine, are also included. The 

 major part of the memoir is taken up with minute descriptions of the 

 species which, according to Professor Williams, has been mostly 

 the work of his assistant, Mr. C. L. Breger. More than a hundred 

 species are discussed belonging to the groups Cephalopoda, Gastro- 

 poda, Pelecypoda, Trilobita, Ostracoda, and some Plant remains 

 (? Psilophyton), as well as a fish fragment (Asterolepis clarkei, 

 Eastman), the Brachiopods and Pelecypods being, however, the more 

 abundant organisms. Some- fifty or more new species are established, 

 together with the following new genera and sub-genera — Pelecypoda : 

 Preavicula type — Megambonia oblonga, Hall ; Sphenotomorpha type 

 = S. rigidula, n.sp. ; Grammysioidea type = G. princiana, n.sp. ; 

 Nuculoidea type =JV^uctila opima, Hall. Brachiopoda : Antispirifer 

 type=^4. harroldi, n.sp. Ostracoda: Zygobkyrichia type = Z. apicalis, 

 n.sp., and including also Beyrichia devonica of Jones & Woodward, 

 from the Lower Devonian of England. 



The fauna of the Chapman Sandstone is regarded as of true Lower 

 Devonian age, with affinities to the Helderbergian fauna of New 

 York, but characterized by more numerous European types than the 

 typical Helderbergian. Compared with Europe, the Chapman fauna 

 shows affinities with the Lower Devonian, particularly that portion 

 of it below the Upper Coblenzian. It is, moreover, said to be a later 

 fauna than the Tilestone or Downtonian of England, or the terminal 

 marine fauna of Arisaig, Nova Scotia, being besides recognized as of 

 earlier age than that of the Moose River Sandstone, which may be 

 correlated with the Oriskany Sandstone of New York and the York 

 River (Gaspe Sandstone) of Gaspe Peninsula. 



In a footnote on p. 27 the date of Leptcena explanata by J. de C. 



