STUDIES IN FOBAMINIFERA 



221 



narrow, and extending along the sutiu-e from the um- 

 bilicus toward the periphery rather than across the 

 umbilical margin of the chamber as in the other genera 

 mentioned above. Nevertheless the granular wall 

 structure, trochoid coiling, and apertural flap definitely 

 show the present genus to belong to the Chilostomel- 

 lidae. 



Pallaimorphina ruckerae Tappan, new species 

 Plate 71, Figures 1-9 



Test free, small, trochoid, rotund, and biconvex, 

 periphery broadly rounded ; four to five inflated cham- 

 bers per whorl, increasing gradually in height and 

 rapidly in length as added, so that chambers of final 

 whorl are crescentic in dorsal view, about twice as 

 long as high; sutm-es distinct, slightly depressed, 

 curved and oblique dorsally, nearly straight and radial 

 ventrally; wall calcareous, finely perforate, siu-face 

 smooth; apertiu-e a low sutural slit, extending from 

 the umbilicus about half the distance to the periphery, 

 bordered above by a narrow lip. 



Greatest diameter of holotype 0.21 mm., thickness 

 0.16 mm. Paratypes range from 0.13 to 0.36 mm. 

 in diameter. 



Remarks: Pallaimorphina ruckerae, new species, 

 differs from Qvxidrimorphina allomorphinoides (Reuss) 

 in lacking an extremely broad spatulate apertural flap, 

 having instead only a very narrow one. It is also 

 much smaller and the chambers are subglobular, 

 increasing gradually in size, without developing the 

 extremely radial elongate final chamber characteristic 

 of Q. allomorphinoides. Very small young specimens 

 of Reuss' species tend somewhat to resemble the present 

 species, suggesting that this genus may be ancestral 

 to Quadrimorphina. 



The species occiu-s in the Grandstand, Topagoruk, 

 and Fortress Mountain formations. It is named in 

 honor of Florence Rucker, geologist, U. S. Geological 

 Survey. 



Type and occurrence: Holotype (USNM P 4664) 

 and figured paratype (USNM P4665) from a core at 

 533-543 feet, figured paratypes (USNM P4666a,b) 

 and unfigured paratypes (USNM P4667) from a core 

 at 206-211 feet, unfigured paratypes (USNM P4668) 

 from a core at 238-256 feet, figured paratype (USNM 

 P4669) and unfigured paratypes (USNM P4670) from 

 a core at 256-266 feet, figured paratypes (USNM 

 P4671a,b) from a core at 273-283 feet, unfigured 

 paratypes (USNM P4672) from a core at 338-348 feet, 

 figured paratype (USNM P4673) from a core at 358-368 

 feet, unfigured paratypes (USNM P4674) from a core 

 at 438^43 feet, unfigured paratypes (USNM P4675) 

 from a core at 503-513 feet, unfigured paratypes 

 (USNM P4676) from a core at 533-543 feet, unfigured 

 paratypes (USNM P4677) from a core at 565-578 

 feet, unfigured paratypes (USNM P4678) from a core 

 at 663-673 feet, all in the Grandstand formation; and 

 unfigured paratypes (USNM P4679) from a core at 

 1,000-1,010 feet in the Topagoruk formation; all from 



396818—57 16 



Simpson test well 1, at lat. 70°57'05" N., long. 

 155°21'45" W., west of Cape Simpson, northern 

 Alaska. 



Figured paratype (USNM P4680) from a core at 

 464}^ feet in the Grandstand formation, in Umiat 

 test weU 2, at lat. 69°23'04" N., long. 152°05'01" W., 

 north of Umiat, in the northern foothills of the Brooks 

 Range, northern Alaska. 



Unfigured paratj^es (USNM P4681) from a core 

 at 256-264 feet and unfigured paratypes (USNM 

 P4682) from a core at 461-466 feet aU in the Grand- 

 stand formation, in SkuU Cliff core test 1, lat. 70°55' N., 

 long. 157°38' W., between Point Barrow and Point 

 Franklin, northern Alaska. 



Unfigured paratypes (USNM P4683) from a core 

 at 558-568 feet in the Topagoruk formation, in Arcon 

 Point Barrow core test 1, at lat. 71°19'30" N., long. 

 156°40' W., southwest of Point Barrow, northern 

 Alaska. 



Unfigured paratype (USNM P4684) from well cut- 

 tings at 2,545-2,550 feet in the Grandstand formation 

 and unfigured paratype (USNM P4685) from well 

 cuttings at 4,820-4,830 feet in the Topagoruk forma- 

 tion, all in Umiat test well 1, at lat. 69°23'52" N., long. 

 152°19'45" W., in the northern foothills of the Brooks 

 Range, northern Alaska. 



Unfigured paratypes (USNM P4686) from the 

 Cretaceous, probably equivalent to the lower part of 

 the Nanushuk group of the eastern areas (field sample 

 47A Ba 83), 903-1,043 feet above the base, south and 

 east of the Utukok River and 2% miles west of the 

 confluence of Disappointment Creek with the Utukok 

 River, at lat. 69°15' N., long. 159°57' W., about 70 

 miles east of Cape Beaufort, in the northern foothills 

 of the Brooks Range, northern Alaska. Collected by 

 W. L. Barksdale, 1947. 



Unfigured paratype (USNM P4687) from the upper 

 part of the Torok formation (Topagoruk formation 

 equivalent) (field sample 47 A Tr 161), on the north 

 flank of the Awuna anticline, at lat. 69°11'42" N., 

 long. 156°45' W., in the Awuna River region, northern 

 foothills of the Brooks Range, northern Alaska. Col- 

 lected by M. L. Troyer, 1947. 



Unfigured paratypes (USNM P4688) from the Topa- 

 goruk formation (field sample 48 A Wb 24), at the 

 confluence of Reynard Creek with the Colville River, 

 northeast of Noluk Lake, at lat. 69°06'30" N., long. 

 159°27' W., in the northern foothills of the Brooks 

 Range, northern Alaska. Collected by E. J. Webber, 

 1948. 



Unfigured paratype (USNM P4689) from the For- 

 tress Mountain formation (field sample 49A Pa 90), 

 on the north limb of the Fortress Mountain syncline on 

 Fortress Creek, at lat. 68°35'10" N., long. 153°10'30" 

 W., and unfigured paratype (USNM P4690) from the 

 Fortress Mountain formation (field sample 49A Pa 94), 

 at lat. 68°35' N., long. 153°10' W., on the syncline 

 along Fortress Creek, tributary to the Ayiyak River, 



