384 



WM. H. EASTON 



are considered very sensitive to environ- 

 mental changes, hence, it appears that mi- 

 grational routes must have existed between 

 the Kinkaid sea of Illinois and the Pitkin 

 sea of Arkansas. Caninostrotion is abundant 

 in the upper part of the Pitkin and common 

 in only one observed bed of the Kinkaid, but 

 on the other hand Kinkaidia is abundant in 

 one bed near the top of the Kinkaid and has 

 only been reported once from the (upper 

 part of the) Pitkin. Considerably more work 

 must be done on these faunas, especially on 

 that of the Kinkaid, before definitive con- 

 clusions can be reached regarding connection 

 of the seas. Even so, a partial emendation of 

 the writer's previous views is in order. 



The writer has stated (Easton, 1943, pp. 

 128-129) that "faunal migration from 

 Europe or Asia apparently reached this 

 ocean [lying south of North America] and 

 certain corals of unique aspect migrated 

 northward with the Pitkin sea but were un- 

 able to cross into the Illinois Basin," and 

 that "there appears to be no evidence that 

 the two basins were directly joined in Pitkin 

 time." The extension of knowledge presented 

 in this paper concerning the geographic dis- 

 tribution of the corals shows that the two 

 basins probably were connected and that 

 favorable ecologic conditions of unknown 

 duration enabled faunal migration of some 

 distinctive organisms. Not all of the Pitkin 

 corals are yet known to have lived in the 

 Illinois region during Kinkaid time and 

 many other distinctive faunal elements 

 either remain undiscovered in strata of the 

 adjacent seas or actually did not cross a 

 possible ecologic barrier between the seas. 



ACKNOWLEDGMENTS 



Collections were made with the assistance 

 of Mr. C. L. Cooper and Mrs. Phoebe Beall 

 Easton. Mr. G. A. Cooper lent Pitkin mate- 

 rial for study and Mr. J. E. Lamar con- 

 tributed information concerning his work at 

 the Kinkaid locality. 



SYSTEMATIC DESCRIPTIONS 



The morphologic terminology used in this 

 paper has been outlined previously by the 

 writer (Easton, 1944). 



Phylum Coelenterata 



Class Anthozoa 

 Order Tetracoralla 

 Family Metriophyllidae 

 Genus Kinkaidia Easton, n. gen. 



Diagnosis. — Simple, curved to cylindri- 

 cal, rugose corals; counter septum long, may 

 be rhopaloid; pair of counter-lateral septa 

 bordering counter septum rather long, may 

 be rhopaloid; cardinal septum short except 

 in young stages; alar septa long, may touch 

 counter septum even in mature stage; other 

 major septa of equal strength, withdrawn 

 from axis in mature stage, commonly rho- 

 paloid; minor septa rudimentary; tabulae 

 distally arched, both complete and incom- 

 plete types present; tabellae sparse, broadly 

 arched; dissepiments absent. 



Genotype. — Kinkaidia trigonalis, n. sp. 



Remarks. — This genus differs from Clavi- 

 phyllum Hudson, 1942, in having long alar 

 septa in late stages, a relatively long coun- 

 ter-lateral septum on each side of the coun- 

 ter septum, and tent-like rather than globose 

 tabellae. The two genera are very closely 

 related, Kinkaidia being a potential ancestor 

 of Claviphyllum ; the former could give rise 

 to the latter by reduction in length, of the 

 alar septa, by insertion of short septa be- 

 tween the counter septum and the counter- 

 lateral septa, and by increase in complexity 

 of the tabellae. 



Sochkineophyllum Grabau, 1928, is also 

 related to Kinkaidia, differing from it in the 

 absence of long alar septa and the long coun- 

 ter-lateral septum on either side of the 

 counter septum, and in having several pairsof 

 long rhopaloid (axially swollen) major septa. 



Malonophyllum Okulitch and Albritton, 

 1935, though possessing the same general 

 characters as the foregoing genera, lacks 

 tabulae. 



Lophophyllidium Grabau, 1928, may have 

 been derived from Kinkaidia by reduction 

 in length of the alar septa and by loss of the 

 rhopaloid character of the major septa in 

 late stages. The two genera resemble each 

 other in the relative lengths of major septa 

 (other than alars), in the nature of the ta- 

 bulae, in the absence of dissepiments, and 

 in the inconsistent development of minor 

 septa. The stratigraphic occurrence of these 



