28 LINNARSSON, BRACHIOPODA OF THE PARADOXIDES BEDS. 



Belle Isle, seem to belong to the Paradoxides period, as they 

 are said to be associated with Olenellus Thompsoni, which has 

 no affinity to Olenus, but is a true Paradoxides (or Anopolenus). 

 Of the species described in the second volume Obolella jnisera, 

 and probably Iphidea bella belong to the Paradoxides period. 

 Finally, Mr. Meek has described from Montana one species, 

 Iphidea (?) sciäptilis, ') which is probably of the same age. 



These are, as far as I know, all the Brachiopoda hitherto 

 published from the Paradoxides beds of Europé and America. 

 The number of forms which have received distinct specific 

 names is about 29. Several species have also been men- 

 tioned to which no specific name has been assigned. Even 

 inclnding these latter, the Brachiopoda are few in number, 

 when compared Avith the Trilobites, of which already about 

 150 species have been described, new ones being added in 

 quick succession. Mr. Barrande states in 1871 -) the total 

 number to be 168, but this number is too high, as he com- 

 prises the whole Swedish Primordial zone in the "Phases a 

 Paradoxides". In the Olenus beds not a single Paradoxides 

 occurs, nor any representatives of most other Trilobite genera 

 characterizing the Paradoxides beds in Sweden, as well as in 

 other countries. It is not unlikely, however, that this number 

 will soon be reached, or even surpassed. Next to the Tri- 

 lobites the Brachiopoda are the most important part of the 

 fauna of the Paradoxides beds. As the Brachiopoda in general 

 have a far wider range in time than the Trilobites, it is not 

 to be expected that the Brachiopod fauna of the Paradoxides 

 beds will show so striking peculiarities as the Trilobite favma, 

 though the facts hitherto known tend to show that the Pa- 

 radoxides beds contain many peculiar types also araong the 

 Brachiopoda. How far the differences in this respect extend 

 between the Paradoxides beds and the overlying formations it is 

 not, at present, possible to ascertain with full certainty, as the 

 limits of many of the genera are still very uncertain, and 

 probably many species ought to be referred to other genera 

 than those to which they have hitherto been referred. In 

 general, the Paradoxides beds are chiefly characterized by most 

 of their Brachiopoda having a corneous shell, composed of 



') Sixth Annual Report of the United States Geological Survey of the Ter- 



ritories. 1873. p. 479. 

 2) Trilobites, p. 195. 



