CAMBRIAN BRACHIOPODA — WALCOTT IO9 



ible median sinus serve to distinguish this species from all described 

 forms. 



This is the oldest shell of this type known to me. It occurs 5,465 

 feet (1,665.7 m.) below the summit of the Cambrian, in the House 

 Range Section. I am not fully satisfied with the generic reference, 

 but with the data available it can not well be referred to BillingscUa 

 or any other known genus of the Cambrian Brachiopoda. 



Formation and Locality. — Middle Cambrian: About 2,250 feet 

 (685.8 m.) above the top of the Lower Cambrian and 2,150 feet 

 (655.3 "''•) below the Upper Cambrian, in the gray shaly limestones 

 of the Marjum formation. House Range Section, 2.5 miles (4.02 

 km.) east of Antelope Springs, in ridge surrounding Wheeler Am- 

 phitheater, House Range, Millard County, Utah. 



HUENELLA, new genus 



This genus is proposed to include the more or less plicate species 

 of the Syntrophiidje that have heretofore been referred by me to the 

 genus Syntrophia. They differ from Syntrophia in having a more 

 or less radially plicate surface and sessile or pseudo spondylia instead 

 of free spondylia supported by a median septum. With the possible 

 exception of HueneUa etheridgei (see below), all of the species are 

 from the Upper Cambrian. 



The shell structure is fibrous, with man}^ minute pores. 



Typu. — Syntrophia te.vana Walcott [1905a, p. 294]. 



The generic name is given in recognition of the thorough and 

 valuable work of Dr. F. von Hoyningen-Huene on the "Silurischen 

 Craniaden." 



HUENELLA ETHERIDGEI, new species 



Plate; 10, Figures 13 and iT,a 



Orthis (or Orthisina), sp., Etheridge, 1905, Trans. Roy. Soc. South 

 Australia, XXIX, p. 250, pi. xxv, figs. 9 and 10. (Described as below 

 and discussed. The specimens represented by figures 9 and 10 are 

 redrawn in this paper, pi. 10, figs. 13 and 13a.) 



Dr. Etheridge describes the ventral valve as follows : 



"Subquadrilateral, convex, the greatest convexity at about midway 

 in the length of the valve, the sinus gradually deepening and widen- 

 ing toward the front, and bounded laterally by ill-defined folds, one 

 on either side, the surface sloping away on either side rapidly to the 

 lateral margins and at a very mtich less angle within the sulcus ; 

 there are indications of cost?e on the divaricating folds and in the 

 siilctis. 



"The hinge features arc hidden in matrix, nor is the umbo dis- 

 tinctly visible." 



