608 



Karl A. Grönwall. 



t Productus inflatus M'Chesn. PC. 



t — boliviensis D'Orb. PC. 



t — cancriniformis Tschern. P. 



(* Martinia corciilum Кит.) P. ?. = 6 Sp. 



E. * Chonetella nasuta Waag. 



t Productus compressus Waag. = 2 Sp. 



In a tabulated summary the ratios existing between these various 

 divisions of the species can be expressed as follows: 



In this table consequently, the species that are either restricted 

 to the Upper Carboniferous, or, from that level ascend into the 

 Permo-Carboniferous or the Permian, are in a decided majority, as 

 they form 8 + 6=14 species, or ^1-л of the entire number. Another 

 striking fact is, that there is no species here that is restricted to 

 the Lower Carboniferous, so that we must consider the possibility 

 of these formations from North-east Greenland belonging to the 

 Lower Carboniferous deposits, as being entirely excluded. As regards 

 the possibility of a Permo-Carboniferous or a Permian age for these 

 formations or for any part of them, this, in consequence of the fauna- 

 elements, cannot, of course, be denied, especially when we take into 

 consideration that such a large proportion of the collections was 

 made from talus boulders or free-lying fragments. However, the 

 support given by the fauna for a younger age than the Upper Car- 

 boniferous is not specially strong. Of the species, Div. D., which, 

 from the Upper Carboniferous deposits ascend into the Permo-Car- 

 boniferous and the Permian, there is none that can be considered 

 as a precursor of the Permian fauna, but all of them possess a purely 

 Carboniferous character. Of the two forms that, hitherto, have been 

 found only in Permian deposits, Productus compressus Waag. is a 

 purely Carboniferous type, with closely related forms, in the Upper 

 Carboniferous above all, but also in the Lower Carboniferous deposits, 

 while Clionetella nasuta Waag. is a more isolated type of the family 

 Productidœ which has by no means any special younger character, 

 but can very well be derived from older species of Chonetes. Hall 

 and Clarke (Vol. I, p. 313) say speaking of the genus Chonetella: 

 "Aside from the broadly curved brachial ridges, its characters are 



