GEOLOGICAL AND GEOGRAPHICAL DISTRIBUTION. 131 



ding to M. C. Burrois l , the mosl recent writer on the Bubject, to the Lower Devonian 

 scries; but they are situated at a relatively higher level in it than the Grfs de Gahard 

 in France, though probably at nearly the same horizon as Pentremitidea Fraiponti 

 in Belgium (Coblencien superieur). 



It is possible thai another genus may occur in these Spanish beds. According to 

 Roeiner-, de Yerneuil's collection from the Asturias contained a Blastoid resembling 

 Orqphocrinus vents, Cumbld. sp. (=Pentatrematites inflata, G. IS. shy.). This is to a 

 certain extent borne out by an illustration given by Don Lucas Mallada 8 , who figures 

 this identical species as a Spanish Devonian Blastoid. Unfortunately, however, his 

 figure is only an exact reproduction of that given by Phillips of the British Carbo- 

 niferous fossil 4 . We have been unable to obtain any information about de Yerneuil's 

 collection, and can therefore offer no opinion on the subject. 



The Devonian rocks of the Eifel and Rhine have, with any certainty, yielded only 

 one genus, Pentremitidea. Goldfuss described what appears to be a veritable 

 Pentremites from the slaty beds below the Carboniferous Limestone near Dusseldorf •' ; 

 but we have reason to believe that this species is really of Carboniferous age. 

 Pentremitidea is wholly confined, so far as we can ascertain, to the Middle Devonian 

 and to two horizons therein, viz. the Eifeler-Kalk of the Eifel l) , and the Stringoce- 

 phalen-Kalk of Nassau. Of the six species at present known, five are peculiar to the 

 former locality and one to the latter. One of the five is likewise met with in Spain. 



A great increase in Blastoid life is displayed in the Devonian rocks of the North- 

 American continent. There is evidence of four or possibly of six genera, containing 

 amongst them a large number of species. Two genera are peculiar both to the 

 country and to the formation, and do not pass upwards into the Carboniferous, viz. 

 Eleiitherocrinus and Elmacrinus. 



Each of these is represented both in the Upper Helderberg or Corniferous Group 

 of the Lower Devonian, and in the Hamilton Group of the Upper (or X Middle) 

 Devonian. Eleutherocrinus has a species common to both horizons, and a second 

 one in the Hamilton Series ; while there are three species of Eloeacrinus in the Lower, 

 and five in the Upper Devonian, none of which last occur in the lower beds. 



Schizollastus, a closely allied genus to Ehvacrinus, also seems to make its first 

 appearance in the Upper Devonian, being represented by one of the two specimens 

 described by Shumard 7 from the Chemung Group at Providence, Missouri, under the 



1 Mem. Soc. Gcol. Nord, 1882, tome ii., Mem. 2, p. 518 ; Compt. Rend. Assoc. Franc. 1883 [1884], p. 448. 



2 Archiv f. Xaturgesch., 1851, Jahrg. xvii. Bd. i. p. 375. 



5 Bol. Com. MapaGeol. EspaSa, 1877, tomo iv. lam. 12. f. 11. 

 * 111. Gcol. York. pt. 2, 1836, t. 3. f. :;. 



5 Petrefacta Gcrmaniiu, Theil i. p. 161, t. 50. 



6 Contrary to most writers, Barrois considers this as a portion of the Lower Devonian. 

 ' Swallow's 1st and 2nd Missouri Gcol. Report, 1885, t. B. 



c9 



