346 Miscellaneous. 



Saurocephcdus albensis and hifluens, Pict. et Camp., S. dispar, Heb., 

 and S. incequalis and sabstriatus, Miinst., are founded on isolated 

 teeth ; and their affinities are regarded by the author as doubtful. 

 Saurodon Leanus, Hayes, from the Greensand of New Jersey, belongs 

 to Saurocephalus, which also includes a species described by Prof. 

 Cope under the name of S. arapahovius. Teeth erroneously referred 

 by Agassiz to Saurodon Leanus were regarded by Dr. Leidy as re- 

 presenting a new genus and species, Cimolichthijs levesiensis ; and to 

 this last-named genus the author refers Spinax marginatus, Reuss, 

 and, doubtfully, Saurocephcdus striatus, Ag. 



3. " On some well-defined Life-zones in the Lower Part of the 

 Silurian (Sedgw.) of the Lake-district." By J. E. Marr, Esq. Com- 

 municated by Prof. T. M'K. Hughes, M.A., E.G.S. 



This paper treats of the zones of fossils occurring between the 

 Coniston Limestone and Coniston Grits, with a view to establishing a 

 boundary between the Cambrian and Silurian formations. In the 

 lake-district beds the genus Phacops is very abundant, one or more 

 species of its subgenera characterizing each fossiliferous formation. 

 The zones thus indicated are found to hold good when the organic 

 remains as a whole are considered. The author separates the Ash- 

 gill shales from the Coniston Limestone, giving separate lists of 

 fossils to show the palaeontological difference — from which it appears 

 that but few (and those the very common Bala fossils) are common 

 to both, while the most characteristic Ashgill fossils do not occur in 

 the Coniston Limestone. They indicate that the Ashgill formation 

 is Upper Bala. It is very irregular in thickness ; and the author 

 thinks this due to an unconformity above the Ashgill beds. Here 

 the author agrees with Prof. Hughes in placing the base of the 

 Silurian. He gives lists of the fossils in the basement bed and tho 

 Stockdale Shales, and points out that their facies is distinctly 

 Silurian. Very few fossils are common to them and the Coniston 

 Limestone or Ashgill Shales. Hence there is here both a physical 

 and a paheontological break ; so that the division between Cambrian 

 and Silurian should be placed at this horizon. A detailed description 

 (with lists of fossils) is given of the Coniston Flags and Coniston 

 Grits. An appendix contains some palseontological notes on some 

 species of the genus Phacops. 



MISCELLAI^EOUS. 



Oil the Parasitic Isopoda of the Genus Entoniscus. 

 By M. A. GiARD. 



The singular parasitic Isopods discovered and described by Fritz 

 Miiller under tlio generic name of Entoniscus, have hitherto been 

 detected onlv on the coast of Brazil. I have to indicate the axis- 



