214 



UNITED STATES NATIONAL MtJSETJM BULLETIN 215 



Trochammina stefansBoni Tappan, new specieB 

 Plate 67, Figures 30-33 



Test free, trochoid, low spired, periphery rounded; 

 all chambers of the approximately two whorls visible 

 dorsally, only the nine of the final whorl visible on the 

 umbUicate ventral side, chambers increasing rapidly in 

 size, early ones subglobular, later cuneate in side view; 

 sutxu-es distinct, depressed, radial; wall very finely 

 arenaceous, with considerable cement and smoothly 

 finished, all specimens crushed and distorted in preser- 

 vation ; apertm-e an arch at the base of the final chamber 

 face, against the previous whorl on the periphery. 



Greatest diameter of holotype 0.55 mm. Paratypes 

 range from 0.31 to 0.62 mm. in diameter. 



Remarks: Trochammina stefanssoni, new species, 

 differs from T. diagonis (Carsey) in having more cham- 

 bers to each whorl and in the chambers being cuneate 

 rather than rounded and inflated. It is also more finely 

 arenaceous and more smoothly finished. 



This species has been found only in the Sentiuel HUl 

 member of the Schrader Bluff formation (Upper Cre- 

 taceous) . The specific name is in honor of Karl Stef ans- 

 son, geologist, formerly of the U. S. Geological Siu-vey. 



Types and occurrence: Holotype (USNM P4490) 

 and imfigured paratypes (USNM P4491) from a core 

 at 475-476 feet, figured paratj^ies (USNM P4492a-c) 

 and unfigured paratypes (USNM P4493) from a core 

 at 478^80 feet, and unfigured paratypes (USNM 

 P4494) from a core at 579-589 feet, all from the Sentinel 

 Hill member of the Schrader Bluff formation, in Sen- 

 tinel Hill core test 1, at lat. 69°35'48" N., long. 

 151°28'09" W., on the west bank of the Colville River, 

 Arctic Coastal Plain, northern Alaska. 



Trochammina umiatensis Tappan, new Bpecies 

 Plate 67, Figures 27-29 



Test free, trochoid, relatively high spired, periphery 

 lobxalate and roimded; chambers inflated and subglob- 

 ular, few in number, increasing rapidly in size, only 

 four or rarely five in each whorl; sutures distinct, de- 

 pressed, radial; wall finely to coarsely agglutinated, 

 roughly finished ; apertm-e ventral, a slit at the base of 

 the final chamber face. 



Greatest diameter of holotype 0.68 mm., thickness 

 0.29 mm. Paratypes range from 0.29 to 0.81 mm. in 

 diameter. 



Remarks: Trochammina umiatensis, new species, 

 differs from T. glohigerinijormis (Parker and Jones) in 

 having more chambers per whorl, commonly four in- 

 stead of the three of T. glohigerinijormis, in being nearly 

 three times as large, and in having a better developed 

 and higher spire and a greater increase in chamber size. 



Types and occurrence: Holotype (USNM P4495) 

 from well cuttings at 735-740 feet in the Grandstand 

 formation, m Umiat test well 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 paratypes (USNM P4500) from a core at 

 1,615-1,625 feet and unfigvired paratype (USNM 



P4501) from a core at 1,625-1,635 feet, both in the 

 Grandstand formation, in Umiat test well 1, at lat. 

 69°23'52" N., long. 152°19'45" W., west of Umiat, in 

 the northern foothflls of the Brooks Range, northern 

 Alaska. 



Figured paratypes (USNM P4502a-b) from a core 

 at 1,130-1,133 feet, unfigured paratypes (USNM 

 P4503) from a core at 1,183-1,186 feet, and unfigured 

 paratypes (USNM P4504) from well cuttings at 1,190- 

 1,195 feet, all in the Grandstand formation, in Umiat 

 test well 8, at lat. 69°23'59" N., long. 152°06'56" W., 

 north of Umiat, in the northern foothills of the Brooks 

 Range, northern Alaska. 



Trochanunina whittingtoni Tappan, new species 

 Plate 68, Figures 3-6 



Test free, trochoid, much compressed; chambers nu- 

 merous, increasing gradually in size, eight to nine in the 

 final whorl; sutures slightly depressed, radial; wall 

 finely agglutinated, probably with a "chitinous" base 

 as all specimens are laterally crushed in preservation 

 and of a brownish color, with chambers collapsed cen- 

 trally; aperture obscured by the lateral compression of 

 the test. 



Greatest diameter of holotype 0.49 mm. Paratypes 

 range from 0.26 to 0.73 mm. in diameter. 



Remarks: This species differs from T. diagonis 

 (Carsey) in having more chambers per whorl and hav- 

 ing a characteristic brownish color and fine-grained wall, 

 with its usual lateral compression. 



The species occurs in the Seabee and Schrader Bluff 

 formations of the Upper Cretaceous. It is named in 

 honor of C. L. Whittington, geologist, U. S. Geological 

 Sm-vey. 



Types and occurrence: Holotype (USNM P4505), 

 figm-ed paratype (USNM P4506), and unfigured para- 

 types (USNM P4507), aU from the Seabee formation 

 (field sample 47A Wh 295), taken 541-545 feet below 

 the top, on September Creek, Knifeblade area, between 

 the Kigalik and Awuna Rivers, at lat. 69°11' N., long. 

 154°34' W., in the northern foothills of the Brooks 

 Range, northern Alaska. Collected by C. L. Whiting- 

 ton, 1947. 



Figiu-ed paratype (USNM P4508) and unfigured 

 paratype (USNM P4509) taken 20 feet above the base 

 of the Seabee formation (field sample 47A Dt 80) and 

 unfigured paratypes (USNM P4510) taken 210 feet 

 above the base of the Seabee formation (field sample 

 47A Dt 125), all from the vicinity of the Colville River, 

 west of Ninuluk Creek, at lat. 69°13' N., long. 153°15' 

 W., in the northern foothills of the Brooks Range, 

 northern Alaska. Collected by R. L. Detterman, 1947. 



Unfigured paratypes (USNM P4511) taken 140-160 

 feet above the base of the Ayiyak member of the Seabee 

 formation (field sample 48A Dt 377), at lat. 69°10' N., 

 long. 151°27' W., and unfigm-ed paratypes (USNM 

 P4512) taken 990-1010 feet above the base of the 

 Rogers Creek member of the Schrader Bluff formation 

 (field sample 48 A Dt 422), at lat. 69°14' N., long. 



