152 ROYAL SOCIETY OF CANADA 



Of these the Niagara formation is referable to the Silurian System and 

 the remainder to the Ordovician or Caml)ro-Silurian System. 



The Potsdam Sandstone Formation. 



The characteristic fossils of the Potsdam formation in the Ottawa 

 Palaeozoic Basin comprise the following tracks or trails of marine 

 organisms : — Climactichnites WiJsoni, Logan, Protichnites oeto-notatus, 

 Owen, P. lineatus, Owen, Scolithus Canadensis, Billings. Ophilcfa com- 

 planata, Vanuxem. Lingulepis acuminata. Conrad sp., together with 

 Falœophycus Bevei'leyensis, Billings, besides obscure remains of Orthoce- 

 rata have also been found in l)eds of this age. No truh' primordial fossils 

 have as yet been recorded from the Potsdam sandstone formation of the 

 Ottawa Paljeozoie Basin such as have been found in the Potsdam of New 

 York. Wisconsin and Minnesota. The Dikelocephalus and Conocephalites 

 zones are not as yet known to exist anywhere in this basin. 



The Calciferous Formation. 



The Calciferous fossils of the Ottawa Palaeozoic Basin are not numer- 

 ous, but are of considerable interest and importance, and include the fol- 

 lowing : — Metoptoma simplex, Billings, Pleurotomaria calcifera. Bill., P. 

 Canadensis, Bill., Hormotoma Anna, Bill., H. Artemisia, Bdl., Tarritoma 

 Ada, BWL, Oxydiscus 'macer,H\\\., Ophileta complanat a, Y nimxom (— 0. 

 compacta, Salter, of Can. Org. Eem., Decade I.), Ophileta disjancta, Bill- 

 ings, JIaclurea abdita. Bill., Jjituites Apollo. Billings, Orthocerasvcterator, 

 Bill.. 0. Lamarcki, Hill., 0. edax, Bill., 0. Cilducus, Bill., Ajnphion S((lteri, 

 Bill., Bathyurus Cybele, Bill., Polichometopus rarus, Billings, Ribeira 

 calcifera, Bill., Ji. lonf/iuscula, Bill. The best localities for collecting 

 fossil organic remains in this basin are Lot 3, Con. IV., Oxford, Ont., 

 near Merrickville, the counties of Leeds and Grenville, near Carillon, 

 Que., and ]jachute. Que. The fossil fauna of this formation in this basin 

 is still verj' imperfectly known. 



The Cua/v Formation. 



The fauna of the Chazy is readily distinguished from that of the 

 Calciferous formation, and corresponds to the nature and conditions of 

 sedimentation in those early Ordovician times. The lower beds of the 

 Chazy are arenaceous, and hold the characteristic fossil Scolithus, prob- 

 ably a new form, in great abundance, also an extensive series of tracks 

 and trails of marine organisms, some of which may have been made by 

 gasteropoda, some by trilobites. others by annelids, and others by various 

 other groups of molluscs. Most of these are undescribed. 



The form Rhynchotrema plena. Hall, so abundant at Montreal and 

 in the Lower Ottawa Chazy. has been but sparingly found in the Chaz}' 



