BUFFALO SOCIETY OF NATURAL SCIENCES 101 



moreover, their faunal associates are not typical marine forms, 

 there being only eurypterids, ceratiocarids and the plant Buthro- 

 trepis lesguereuxi, together with a few water-worn specimens of 

 Orthoceras. The writer has elsewhere * discussed at length the 

 significance of this unique fauna and the bionomic conditions 

 which it indicates. The very thin shell of these pulmonate 

 gastropods may be taken as a slight bit of additional evidence to 

 that given in the paper above referred to in support of the view 

 that the Bertie waterlime was deposited not in marine water, but 

 in brackish of fresh water, and that the Hercynellas as well as 

 eurypterids were carried into the Bertie muds by the rivers. If, 

 on the other hand Hercynella is to be regarded as a marine 

 genus, then- we have here another case of intermingling of marine 

 and fluviatile species in the region of deposition at their junction. 



Bulletin of the Geological Society of America, Vol. XXIV, 

 pp. 499-515. 1913. 



Bibliography. 



Barrande, Joachim, 1911. Systeme Silurien du Centre de 

 la Boheme. Premiere Partie, Vol. IV. Gasteropodes. By 

 Jaroslav Perner, Tome III. Prague. (Pp. 270-291, pis.) 



Grabaii, Amadeus W. and Sherzer, William H. , 1910. 

 The Monroe formation of southern Michigan and adjoining 

 regions. Michigan Geological and Biological Survey. Publi- 

 cation 2, Geological Series 1. (Pp. 195-196; pi. XXV. figs. 9,10). 



Kayser, Emanuel, 1878. Die Fauna der altesten Devon- 

 ablagerungen des Harzes. Berlin. (Pp. 101-104, pi. XVII, 

 figs. 9, 10 ) 



Paleeontological Laboratory, 

 Columbia University. 



