December, 1843.] 331 



ated, characterize the upper part of the Caradoc sandstone, (Clinton group of 

 New York.) 



The lead-bearing rock is a buff colored granular limestone, and contains 

 the following species of organic remains, all of which have been found in the 

 Trenton limestone, except the two printed in italics : 



U?iivalves. Bivalves. 



Inachus pervetus, Con. Orthis testudinaria. ? 



Pleurotomaria angulata, Sowerby. Delthyris 



Turritella Strophomena sericea. 



Coral. 

 Cyathophyllum profundum, Con. 



There is also the post-abdomen of an undetermined trilobiteand various forms 

 of crinoideal vertebrae. 



In the Trenton limestone of Mineral Point, the following species of organic 

 remains were collected by Mr. Taylor : 



Shells. Shells. 



Cyrtoceras marginalis, Con. Orthis disparilis, Con. 



Orthoceras annellus, Con. perveta, Con. 



Phragmolites compressus, Con. tricenaria, Con. 



Turritella bellarugosa, Con. 



Pleurotomaria angulata, Sowerby. subequata, Con. 



Bellerophron bilobatus, Sow. Atrypa (Tereb.) Schlottheimii, (Von 



Euomphalus triliratus, Con. Buch.) 



Inachus pervetus, Con. Nuculites, 2 species. 



Subulites elongata. 



Crustacea. 



Delthyris 



Strophomena sericea, Sow. Ceraurus pleurexanthemus, Green. 



deflecta, Con. Isotelus gigas, Dekay. 



recta, Con. Thaleops ovata, Con. 



Orthis testudinaria 1 Cy therina fabulites, Con. 



Thaleops. 



Capite lunato, trilobato, oculis distantibus, eminentissimis, non reticulatis ; 

 trunco 10-articulato, valde trilobato ; lateribus expansis, medio angulatis ; costis 

 integris ; post-abdomine trilobato, minimo ; costis nullis. 



Ovate, profoundly trilobed, lateral lobes wider than the middle lobe ; buckler 

 lunate, with very remote oculine tubercles, not reticulated ; abdomen with 10-ar- 

 ticulations ; ribs without grooves and not alternated in size ; outer half of lateral 

 lobes suddenly depressed ; post-abdomen without ribs or grooves and profoundly 

 trilobed. 



This genus is remarkable for the great width of the buckler, and the very 

 prominent laterally projecting smooth oculine tubercles. It differs from Bumas- 

 tus in being profoundly lobed, and in having the side lobes as in Asaphus much 



45 



