Report of the State Geologist. 



All 



at all, bifurcate, representing a group reaching its maximum in the 

 Lower-Devonian; no representative of Thysanopeltis or the group of 

 Bronteus with spinous pygidial margin, a division of later Devo- 

 nian culmination; Harpes (E and F species); Cheirurus (F and G 

 species); no representative of Dalmanites (Rausmannia) so abundant in 

 the Hercynian and F, G etages. Cephalopods: Species in part identical 

 with those of the Coblenzian and E, F and G. Jovellania (group of Ortho- 

 ceras triangulate), which predominates in the Hercynian. Gastropods: 

 Platyceras in great numbers* (eighteen species), as in the Hercynian; 

 Hercynella (?), a Hercynian genus; Strophostylus (F, Hercynian); Bellero- 

 jjhon Pelops (F, Upper Helderberg); Horiostoma, species allied to those 

 of the Coblenzian limestone and differing from those of the Gotlander- 

 kalk. Lamellibranchs: Limoptera; Paracyclas ; Gonocardium (abun- 

 dant); Cardiola ; Panenka is absent. Brachiopods: Rhynchonellas 

 related to those of the Lower Helderberg and F; Athyris (11 species) 

 represented by Coblenzian forms (a genus rare in the Bohemian, 

 Hercynian and Lower Helderberg); Atrypa reticularis and its varieties 

 (six) ; Ambocoelia umbonata agreeing with Oehlert's identification ; Orthis 

 of the type of 0. striatula; Pentamerus of large size and coarse ribs, char- 

 acterizing the Lower-Devonian limestone faunas (in Europe; Barrois, p. 

 302); Megalanteris ; Spirifer with great median septum (S. robustus); 

 long-winged forms (S. paradoxus var. Hercynice); forms with costate fold 

 and sinus (S. Trigeri, Jouberti) ; in general, species identical or closely 

 related to forms of the Hercynian, and belonging to groups expressive 

 of Devonian age. Corals : Cyathophyllum ; Zaphrentis ; Amplexus ; 

 Heliolites ; Favosites ; Chcetetes ; Alveolites; Striatopora ; Pleurodictyum 

 and Petraia are absent. 



The general harmony of this fauna with the typical Hercynian is 

 apparent even from this brief summary; furthermore, it is evident 

 from the foregoing, and is shown more emphatically in the detailed 

 tabulation of species and their equivalences given by Barrois, that 

 there are many points of alliance with the Bohemian F and G and the 

 Coblenzian. 



At the base of the Devonian system in western Europe is the Gedin- 

 nian (according to Hebert, Murchison, Dumont and Gosselet). " This 

 etage presents a certain number of arenaceous and calcareous equiva- 

 lents. The principal arenaceous facies here cited, are the beds of Mon- 

 drepuits, Looe, Cathervieille, Oriskany; the principal calcareous facies, 



*Les Capulus, Montf., donnent a la faune d'Erbray, un cachet essentiel, par leurabond- 

 ance et la varieto de leurs formes; et si l'usage, preeonise* par quelques auteurs, de 

 designer les Stages par leurs fossiles, tels que VAstartien, le Virgulien, avait preralu, 

 c'est certes, au nom de Capulien, que Ton devrait donner la preference pour designer 

 cette phase de la periode paleozoique." (Op. cit., p. 186.) 



53 



