59 



very nearly allied to" A. Orion which occurs at Point Levis. (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 neAv 

 ones : Lingida Winona, L. Moisa, L. Aurora, Discina mntilis, Obolellat 

 poUta, Orthis Pepina, Platyceras j^rimordialis, ^uom^yJialKs vaticinus 

 Theca primordialis, Serpulites Marchisoni, Dikelocej^halus limhatus D. 

 spiniger, D. 3Iisa, D. Osceola, Conocephalites Eos, G. Perseus ; 0. Shu- 

 mardi, C. nasutics, C. Oioeni, C. JEryon, 0. anatinus, C. Pattersoni 

 C. hinodosus, O. Winona, O. diadematus, C. optatus, 0. nactus, Clia- 

 rioceplialus Whiffieldi, Illcenurus quadratus, Triarthrclla Auroralis 

 Agnostus Josepha, A. p)arili8, A. disparilis, Aglaspis Barrandei, 

 Pemphigaspis hullata, and Amphion matutina. The new genera of 

 trilobites described in this paper are Pempliigasins Aglaspis, Triarthrella, 

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

 Owen's two species, Pikelocephalus Minnesotensis and P. granulosus. All 

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



1864. — Prof. A. Winchell, of Michigan, described Orthis Barahuen- 

 sis, Straparollus ( pi diet a) primordialis, PleurotomariaAdvena,Ptyclias- 

 pis Barahuensis, Palceophycus articulatus, and P, informis, from the 

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

 same locality, Scolithus linearis, D. 3Iinnesotensis and D. Pejnnensis. 



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

 group in Vermont Olenellus Vermontana, 0. Thompsoni and Bathynotus 

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

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

 Archeocyathus Atlanticus, A j^rofimdus, Oholus Lahradoricus, Oholella 

 chromatica, 0. {KutorgincC) cingulata, Orthisina festinata, Camerella 

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

 C. arenosus, Bathyurus senectus, B. pa7-vulus, B. vetulus, B. perp)le.vus, 

 Salterella rugosa, S. pidchella, and S. 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. 



