on the Fossils of the older Deposits in the Rhenish Provinces. 331 



not less so in that of America. Of eighteen species, principally from England and 

 Sweden, some are also found in Esthonia, Livonia, and France. The C.Blumenbachii 

 of Brongniart is, of all the Silurian fossils, that which has been observed in the 

 greatest number of countries : first at Dudley and in the west of England ; then 

 in the slates of Wissenbach and in the grauwacke of Daun ; throughout Scandi- 

 navia and the dependent islands ; in Esthonia*, Ingria, and the west of France ; 

 in the Cedar Mountains of South Africa f ; in the states of Ohio, New York and 

 Tennessee ; and wherever the deposits of this epoch are to be seen from the great 

 lakes as far as Alabama J. Of ten Devonian species, the greater part are from 

 the limestones of the Eifel, and from those of corresponding age in the environs 

 of Elbersreuth and in the Fichtelgebirge. Two species are common to the pre- 

 ceding period : one, the C. macrophthalma, Brong., to which several names have 

 been given, and which, with the C. Sclerops, Dalm., now forms the genus Phacops^, 

 has been noticed in nearly all the countries in which we have observed the C Blu- 

 menbachii, also at Prague, in the Eifel, and in the state of Virginia ; the other, 

 the C Tristani (Brong.), from the west of France, is also found in the grauwacke 

 of the Eifel and to the west of the Cape of Good Hope. The C. concinna of Dal- 

 man is at present the only species which has been observed in the three systems. 



The Homalonoti, which are but few in number, are principally Silurian. H. 

 Knightii of K6nig|| is the most common ; it is found in England, in the grauwacke 

 of the Eifel, and upon the banks of the Rhine, also in the Devonian system of the 

 west of England and at Nehou. The H. Herschelii, Murch., found in the south 

 of Africa %, occurs likewise on the banks of the Rhine. 



The Asaphi are even more plentiful than the Calymene ; forty-six species are 

 Silurian, and particularly noticed in England, Scandinavia, Esthonia, Ingria, and 

 North America. Asaphus caudatus, Brong., A. Hausmannii, id., A. cornigerus, id., 

 are the most frequent in the Silurian deposits on both sides of the Atlantic. Six 

 only are from the Devonian system, and eleven are Carboniferous. The A. granu- 

 liferus of Phillips is found in the two later systems. 



Of eleven species of Paradoxides, nine belong to the lower system in the west of 



* Eichwald, Syst. Silur. Esthonie, p. 70. t Silur. Syst., p. 654:. 



J It is a curious fact, said Mi-. Conrad (Annual Report, 1839, p. 58, 1840), that whilst the C. Blu- 

 menbachii ceased to exist in New York after the final deposition of the Trenton series, it escaped into 

 remote seas and lived in the aera of the Dudley limestone. The Cryptolithus tessellaius, on the contrary, 

 seems to have existed and to have become extinct at the same periods in the seas which deposited the 

 rocks of Llandeilo and Trenton Falls. 



§ Emmerich, De Trilobitis; Berlin, 1839. See Von Buch's Beitrage zur Bestimmung der Gebirgsfor- 

 mationen in Russland; Berlin, 1840, p. 48. 



II Icon. Foss. Sect., Centuria Prima, Tab. VII. f. 85 ; also Silur. Syst. p. 651, PI. VII. f. 1-4. 



t Silur. Syst., p. 652, PL VII. bis, f. 2. 



