BRACHIOPODA. 471 



Karnpylopegmata.] 



On each side the beak of the ventral valve two sharply elevated ridges have 

 their origin, are semicircular in form, and terminate about mid-length on the lateral 

 margins of the valve. These ridges occur in both New York and Minnesota examples. 

 The beak of the ventral valve is strongly incurved and appressed on the umbo of 

 the dorsal valve, with a small pedicle opening which has encroached on the umbo 

 of the ventral valve. Surface, when well preserved, marked by delicate growth 

 lines. 



In the interior of the dorsal valve there is a subangular median septum, origin- 

 ating at the base of the crural plates and extending to near the anterior margin. 

 The brachial supports are very simple in form, consisting of two long recurved 

 primary lamellae, joined near their origin by what appears to be a continuous, 

 slightly bent, transverse band. In some New York specimens there are about two 

 and one-half turns in each spiral, which are somewhat medially directed, and the 

 transverse band appears to be disunited or incomplete. If these differences, more 

 fully noted in the generic description of Cyclospira, prove to exist in nature and are 

 not due to accidental causes, then Mr. Sardeson's specific name, owatonnensis, will 

 come into use for the Minnesota form. 



There is no known species in Lower Silurian rocks with which this form can be 

 compared. 



Formation and locality. This shell is restricted to a limited horizon about fifty feet above the base 

 of the Galena at several localities from three to five miles south of Cannon Falls, Minnesota. It is asso 

 ciated with Plectambonites gibbosa, Orthit meedsi, var. germana and numerous gastropods. In New York 

 it is found at "Adams, Jefferson county, in shaly Trenton limestone associated with Murchisonia and 

 Pleurotomaria, and in a situation where few Brachiopoda occur." It has also been found at Ottawa, 

 Canada. 



Collectors. W. H. Scofleld, E. O. Ulrich and the writers. 



Mus. Reg. Nos. 6762, 8220. 



Suborder KAMPYLOPEGMATA, Waagen. 



Family TEREBRATULID^, Gray. 



Subfamily CRYPTONELLIN^B, Beecher, Ms. 



Genus HALLINA, W. and S. 



1892. Hallina, W. and S. American Geologist, vol. ix, p. 291. 



Shells small, articulate, rostrate, biconvex and semiplicate. Pedicle opening 







usually bounded laterally by incomplete deltidial plates. Calcified brachial sup- 

 ports comparatively long, somewhat longer than half the length of the dorsal valve 

 and in form much as in mature Magellania. The detailed structure of the articula- 

 ting and cardinal processes unknown. In thin sections it is shown that the crural 



