59 



very nearly allied to" A. Orion which occurs at Point Le' vis. (Trans. 

 Acad. Sci., St. Louis, vol. ii, May, 1862). 



1863. PROF. J. HALL revised a number of the above named species 

 from the Potsdam sandstone of Wisconsin, and described the following new" 

 ones : Lingula Winona, L. Moisa, L. Aurora, Distinct inutilis, Obolella ? 

 polita, Orthis Pepina, Platyceras primordialis, Euomphalus vaticinus, 

 Theca primordialis, Serpulites Murchisoni, Dikelocephalus limbatus, D. 

 spiniger, D. Misa, D. Osceola, Conocephalites Eos, C. Perseus ; 0. Shu- 

 mardi, C. nasutus, O. Oweni, O. Eryon, C. anatinus, C. Pattersoni, 

 O. binodosus, O. Winona, C. diadematus, C. optatus, C. nactus, Cha- 

 riocephalus Whitfieldi, Illcenurus quadratus, TriartJirella Auroralis, 

 Agnostus Josepha, A. parilis, A. disparilis, Aglaspis Barrandei, 

 Pempliigaspis bullata, and Amphion matutina. The new genera of 

 trilobites described in this paper are Pemphigaspis Aglaspis, TriartJirella, 

 Illcenurus, Chariocephalus and Ptychaspis. In the last of these is placed 

 Owen's two species, Dikelocephalus Minnesotemis and D. granulosus. All 

 the species are illustrated by excellent figures. (16th Reg. Rep.) 



1864. PROF. A. WINCHELL, of Michigan, described Orthis Barabuen- 

 sis, Straparollus ( Ophiletd)primordialis,PleurotomariaAdvena,Ptychas- 

 pis Barabuensis, Paloeophycus articulatus, and P. informis, from the 

 Potsdam sandstone of Sauk County, Wisconsin. He also reports from the 

 same locality, /Scolithus linearis, D. Minnesotensis and D. Pepinensis. 



In addition to the above, Prof. Hall has described from the Potsdam 

 group in Vermont Olenellus Vermontana, 0. Thompsoni and Bathynotus 

 Holopyga. There will also be found in this work the following twenty-two 

 species, Scolithus Canadensis, Palceophycus incipiens, P. congregatus, 

 Archeocyathus Atlanticus, A profundus, Obolus Labradoricus, Obolella 

 chromatica, 0. (Kutorgina) cingulata, Orthisina festinata, Camerella 

 antiquata, Conocephalites miser, C. Adamsi, C. Vulcanus, C. Teucer, 

 0. arenosus, Bathyurus senectus, B. parvulus, B. vetulus, B. perplexus, 

 Salterella rugosa, S. pulchella, and &. obtusa. 



There are also in Canada certain beds, at present considered to form 

 the upper layers of the Potsdam, which hold Lingula acuminata, Ophileta 

 compacta, Pleurotomaria Canadensis, and a small orthoceratite. It may 

 be that these beds should be placed in the base of the Calciferous, and, 

 therefore, in the following comparisons the fossils they hold will not be 

 taken into account. 



