128 PROCEEDINGS OF THE ACADEMY OF 



position fixed. Coming from a locality difficult of access, and poor in fossils, 

 it seems proper to admit this reference to its existence. 



Collected by A. Wincliell at Point aux Barques, Huron County, Michigan, 

 at the base of the Marshall group. 



Sanguinolites concentkica, Win., (Cardinia concentrica, Win., Proc. Acad. 

 Nat. Sci. Phila., Sept., 1862, p. 413). Collected by A. Wine-hell at Alan's and 

 Germain's quarries, Hillsdale, Hillsdale County, Michigan. 



This species is the analogue of Cardinia tdlinaria, Goldf. sp., (Petr. Germ, 

 ii. ISO, pi. 131, fig. 17), but is more enrolled and more distinctly furrowed. 

 It resembles also, in external characters, Allorisma Hannilmlensis, Shum. 



In the.original description of this species, "ventral," in the second line, 

 should be changed to " vertical." 



Sanguinolites Hannibalensis, Win., {Allorisma Hannibalensis, Shum.) The 

 single specimen collected by the writer at Alan's quarry, Hillsdale, Michigan, 

 less resembles the original figure than it does the Burlington specimens re- 

 ferred to this species. The Hannibal type is more elongate, with broader 

 furrows. 



This species also occurs, satisfactorily identifiable, in both the conglome- 

 rates spoken of under Edmondia. 



Cardiomorpha Julia, Win. Occurs at Napoleon Cut, Jackson County, 

 Michigan. Collected by A. Winchell. 



Leda bellistriata, Stevens. This has been collected by A. W. at Alan's 

 and Germain's quarries, Hillsdale, Michigan. 



CTENODONTA, Salter. 



Ctenodonta Hubbardi, Win., Nucula Hubbardi, Win., Proc. Acad. Nat. Sci. 

 Phila., Sept., 1862, p. 417; ? = Nuculites sulcatina, Conrad, Jour. Acad. Nat. 

 Phila., viii. p. 250, pi. xv. fig. 10). Collected by A. W. at Napoleon Cut, 

 Jackson County. 



Amongst my collections from the Marshall group are numerous specimens 

 generically closely allied to, if not identical with, Nucula, from which I have 

 described N. Hubbardi, sectoralis, stella and lowensis the latter having been 

 originally described by White and Whitfield from the yellow sandstones at 

 Burlington, Iowa. To the Iowa species I have added another N. microdonta. 

 These five species all present a line of teeth continuous from one side of the 

 beaks to the other, without the ligamental pit which belongs to the modern 

 species of Nucula. This variation attracted my attention at the very first ; 

 and I observed that )the hinge characters seemed to identify the species with 

 Tellinomya, Hall, and Ctenodonta, Salter. A species from the Hamilton group, 

 and identified again in the Chemung group, had been described by the subse- 

 quent founder of Tellinomya, as Nucula bellatula, (Rep. 10th Dist. N. Y., p. 

 196) ; and Nucula hians had also been recently described by him (xiii. Rep. 

 N. Y. Regents, p. 110) from rocks of nearly the same age in Indiana, to say 

 nothing of the description by Stevens of N. Eoughtoni, from the Marshall 

 group. Without being acquainted with the details of the hinge structure of 

 these species last mentioned, I yielded to the influence of example in referring 

 my species to Nucula. I did this the more readily, as Prof. Hall had expressed 

 the conviction (x. Report N. Y. Regents, p. 184) that Tellinomya would prove 

 to be a Silurian genus. It may be added to this, that Nucula ventricosa, Hall, 

 (Iowa Rep. p. 716, pi. 29, fig. 4, 5) does not possess the ligamental pit of a 

 modern Nucula, although it offers rather important departures from Telli- 

 nomya.* 



* A fossil from the Coal Measures of Lasalle, Illinois, usually identified with JV. venlricosa, Hall, 

 exhibits no teeth whatever on the anterior side of the beaks, and thus presents generic characteis 

 heretofore unobserved. This feature is shown in several separated valves mineralized by Pyrites. 

 This character would seem to possess equal importance with the absence of the ligamentary pit, 

 on which Ctenodonta has been founded. 



[July, 



