PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 107 
Rafinesquina minnesotensis = Opikina minnesotensis (N. H. Winchell) 
Rafinesquina n. sp. = Opikina 
Rhynchotrema minnesotense = Rostricellula minnesotensis (Sardeson) 
Strophomena plattinensis = S. plattinensis Fenton 
S. p. crassa = S. p. crassa Raasch 
Valcourea deflecta = Campylorthis deflecta (Conrad) 
Zygospira saffordi = Hallina saffordi Winchell and Schuchert 
Division 6.—Thirty-six feet of light-brown to buff dolomitic limestone, fine- 
granular and fairly even textured in thick beds. Two brachiopods, Hesperorthis 
tricenaria and Valcourea deflecta=Campylorthis, are reported. 
Division 7—Limestone, dolomitic, moderately granular and heavy bedded 
with numerous Cryptophragmus antiquatus. The division is about 11 feet thick. 
Brachiopods reported are: 
Rhynchotrema minnesotensis = Rostricellula minnesotensis (Sardeson) 
Strophomena auburnensis = S. auburnensis Fenton 
Valcourea deflecta = Campylorthis deflecta (Conrad) 
Division 8.—Somewhat dolomitic limestone, blue-gray, white-weathering, thin- 
bedded, semilithographic, separated by films of black or gray somewhat car- 
bonaceous shale. The division is 58 feet thick. Fossils are abundant and include 
the following brachiopods: 
Crania setigera = Acanthocrania setigera (Hall) 
Glyptorthis bellarugosa = G. bellarugosa (Conrad) 
Hesperorthis tricenaria = H. tricenaria (Conrad) 
Leptaena charlottae = Bellimurina charlottae (Winchell and Schuchert) 
Rafinesquina cf. hermitagensis = R. trentonensis (Conrad) 
R. minnesotensis = Opikina minnesotensis (N. H. Winchell) 
Rhynchotrema minnesotensis = Rostricellula minnesotensis (Sardeson) 
Strophomena trentonensis Winchell and Schuchert 
Zygospira recurvirostris (Hall) 
Division 9.—Sixty-five feet of cherty, dolomitic limestone containing Colum- 
naria halli in abundance. Hesperorthis tricenaria and Strophomena trentonensis 
are the only brachiopods reported. 
Overlying Division 9 are beds referrable to Trenton rocks and higher. 
Correlation of strata of Kentland area—According to Shrock and Raasch 
(1937), Divisions 4 to 6 are referrable to the Platteville formation ; Division 7 
is assigned to the Lowville (=Carters). Division 8 is referred to the Black 
River but its lower part is thought to be Platteville. Division 9 is Black River- 
Trenton by its position under Division 10, which is assigned to the Galena 
formation. 
Closer correlations may actually be possible in some instances, but they will 
only slightly change the picture as given by Shrock and Raasch. Divisions 4 to 
6 contain a number of brachiopods of which Pholidops [=Craniops] trentonensis 
minor is important. In Minnesota this species occurs in the Ctenodonta bed 
of the Guttenberg member. In Oklahoma Craniops occurs in the upper Bromide 
of about Ridley age. The presence of Rhynchotrema [=Rostricellula] minneso- 
tensis and Pionodema conradi suggest a somewhat earlier dating than Gutten- 
