from. He regards the fossils which occur in these primordial rocks as being of a later age than those found in the primordial zone of Bohemia ; and he looks upon them as representing a period between the first and second faunas of Bohemia *.
This fauna of Hof has no analogy with the ancient fauna of the St. David's promontory. It is altogether much higher in position, and connects the upper portion of the Lingula-flags of Wales, not only with the succeeding Tremadoc rocks, but also with higher members of the Silurian series.
The occurrence of rocks which appertain to the primordial zone of Barrande, in Spain, has been referred to by Sir R. I. Murchison†.
The arrangement of these Spanish representatives of the primordial zone has been given in detail by M. Casiano de Prado‡.
The fauna of the Spanish primordial rocks, which has been obtained from a thin series of red limestones, has been described by Barrande. Among the fossils which it affords are seven Trilobites, referable to the genera Paradoxides, Arionellus, Cenocephalites, and Agnostus. The genus Paradoxides is represented by P. pradoanus, a form which seems to occur only in Spain. The species of Arionellus is A. ceticephalus, Barr., which is a form found in the primordial rocks of Bohemia. There are three species of Conocephalites among the Spanish representatives of the primordial zone, of which two are Bohemian, viz. C. coronatus and C. Sulzeri ; and one form, C. Ribeiro, Barr., has not yet been obtained elsewhere. Two species of the genus Agnostus are also met with in the Spanish primordial rocks. These several Trilobites have been obtained from deposits which lie north of Scabero, and of Bonar, in the province of Leon.
Sir R. I. Murchison also states that MM. de Verneuil and Louis Lartet have discovered a "primordial" Silurian range with the same species of Trilobites near Daroca. They also found it in various parts of the Silurian strata which extend from Daroca to Moncayo §.
The occurrence of fossils, of a type allied to those which are obtained from the rocks of St. David's, has been recognized in several localities in North America. Mr. Salter has mentioned Paradoxides Harlani, Green, as occurring in great quantities in Massachusetts. P. Bennetti, Salter, is found in hard, fine-grained, flinty shales at Branch, in the promontory between St. Mary's and Placentia Bays, Newfoundland ; and Mr. Salter alludes to the occurrence of Conocephalites antiquatus, Salter, as a form which was exhibited at the Great Exhibition, 1851, and which was obtained from a boulder of brown sandstone in Georgia ||.
Dr. Dale Owen has mentioned the occurrence in Wisconsin of several forms of Dikelocephalus, with species of Conocephalites, Ari-
- Faune Silurienne des Environs de Hof, December 1868.
† Siluria, 4th edit. p. 416.
‡ Bull. Soc. Geol. France, 1860, vol. xvii. p. 516 et seq.
§ Siluria, 4th edit. p. 416.
|| " Fossils of the Lingula-flags or Primordial Zone, Quart. Journ. Geol. Soc. vol. xv. p. 551 et seq.
