28 PROCEEDINGS OF THE NATIONAL MUSEUM vol 76 



Zaphrentis ( f) gregaria Rominger. 



Aulacophgllum princeps deflecta Grabau (chironym). 



Blothrophyllum ratiteaui Grabau (chironym). 



Pinnatophyllum scgphus (Rominger). 



HeUophyllum coaUtum (Rominger). 



Prismatophyllum nanum Grabau (chironym). 



Ceratopora near jacksoni Grabau. 



Favosites placenta Rominger. 



F. radiciformis tninus Grabau (chironym). 



TracJvypora near Umhata (Eaton). 



Chonetes fragilis Stewart. 



Spirt fer proHficum Stewart. 



Spirifer near oweni Hall. 



fi*. john^oni Grabau (chironym) 



Leiorhynchus lucasi Stewart. 



Orammysia cf. nodocostata Hall. 



Lophonychia, 2 new species. 



Pterinea near flabcUa (Conrad) and several varieties. 



Phacops milleri Stewart. 



DISCREPANCIES IN FAUNAL DISTRIBUTION 



There can be no reasonable question as to the general age equiv- 

 alence of the Traverse group as developed in western and eastern 

 Michigan, Although a heavy drift cover conceals the actual contin- 

 uity of beds between the two areas, records of wells sunk at various 

 intervals entirely across the region immediately underlain by Middle 

 Devonian rocks establishes the fact that throughout its extent across 

 the northern portion of the Southern Peninsula the Traverse group 

 maintains a thickness close to 700 feet. It is further inconceivable in 

 a region of such comparatively shallow warping that any great 

 thickness of beds deposited in Traverse time was completely removed 

 before the initial invasion and deposition by the early Waverlian 

 sea which soon completely buried the underlying rocks. This ex- 

 planation might be read into the southward thinning of the Traverse 

 beds and the absence in northern Ohio of later Traverse deposits; 

 but abundant evidence is found in the same paleogeographical basin in 

 Ohio and Indiana farther south of continuing Devonian sedimenta- 

 tion. This fact would deny the necessary time for the removal in 

 great part of a continuous sheet of Traverse limestones to the north- 

 ward of the latter area. The Upper Traverse is absent in northern 

 Ohio rather through nondeposition and off-lap to the northward. 

 Why then is there no fauna! connection between the two areas in 

 which the greatest known succession of Traverse beds was developed ? 

 The question can not be answered with the data available at present, 

 and is presented with the hope of stimulating further work on this 

 puzzling problem of faunal distribution. 



Study of the whole area of Traverse outcrop has brought to light 

 only normal conditions of sedimentation throughout the group, and 



