262 NEW YORK STATE MUSEUM 



from the Falkland Islands, Bolivia and South Africa and that 

 others, principally the smaller forms express the local value of S. 

 murchisoni. There are excellent reasons for these views, and 

 though shells like S. primaevus var. atlanticus are ap- 

 parently absent from the New York province yet there is no wide 

 divergence between them and the larger examples of S. mur- 

 chisoni. It will be understood that a proper interpretation of 

 the congeries passing as S. murchisoni in the Oriskany is 

 possible only in terms of well defined localized expressions. 

 Lower Devonic. Baker Brook point, Moosehead lake, Me. 



Cyrtina chalazia nov. 



We are presented in these shells with a departure from the usual 

 aspect of the Devonic Cyrtinas. They are mostly multiplicate shells 

 and in the early stages of this time conform quite generally to the 

 same expression in contour, size and ribbing. Here we have a 

 pauciplicate shell, the dorsal valve of which presents the characters 



Cyrtina chalazia 



which we have noticed as a feature of Spirifer plicatus 

 of the Grande Greve limestones ; few, broad and blunt ribs. The 

 shells are of the small size quite characteristic of the genus with 

 trihedral form and erect or but very slightly curved cardinal area, 

 flat dorsal valve, median sinus and fold well developed, the former 

 having the width of the next two adjoining lateral plications. There 

 are four to five plications on each ventrolateral slope and three to 

 four on the dorsal, the ones nearest the hinge being always very 

 faint. These are in the main broad and smooth and concentric 

 growth lines are usually crowded near the front margin. 

 Lower Devonic. Dalhousie, N. B. 



Trematospira perforata Hall var. atlantica nov. 



Species of Trematospira are almost exclusively of Helderbergian 

 age and the species described are pretty well defined on the basis 

 of their sculpture. In the form before us we have one more nearly 



