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Canadian Revonl of Science. 



of 11 species whit'h is ])rol»iil>ly of Lower Ciiinliriuii Ji<2,e. 

 It (K'ciirs in ji laiiiiiiiited imperfectly oolitie limestone, in 

 oNjil, soniewhiit Hattened masses, the lar<fest of which is 

 18 mm. in its longest diameter. Thev show an obscure 

 eoncenti'ic structure, and an^ mostly in the state of 

 granular calcite, hut in places have the characteristic 

 tuhes of Girvanella, thoui,di less curved ami twisted tiian 

 those of tlie Cha;<y and Silurian specimens, and also of 

 smaller diameter. 



The formation holdinj^ the conglomerate is the Sillery 

 (ri)]»er Camhrian), hut the fossiliferous limestone boulders 

 which it contains are, so far as known, of Lower Cambrian 

 aye, to which therefore the si»ecimens in (juestion may 

 with ]»roba])ility be referred. The ditl'erence in structure 

 as well as in age entitles this form to a s]tecific name. 

 It may be named Girvanella anfiqna, and niay be defined 

 as similar in size and general structure to G. oeellnta of 

 the ("hazy, but with less convoluted and narrower tubes. 



V. KKCElTACrLITFlS, Aucir.KOCYATiir.^, &c. 



In ''The Dawn of Life " (1875), reference was made to 

 tile singular ami complicated organism known as Reeepta- 

 cidites, which at that timi' was generally regarded as 

 Foraminifcral, and is still ]>laced by Zittel, in his great 

 work on Pala-ontology, among forms doubtfully refer- 

 able to that grou]>. It has also been referred to 

 sponges, though on very uncertain grounds. It has 

 not, however, l)een traced, so far as I know, 

 any farther back than the L^i)per Cambrian, and 

 no structural links are known to connect it with (.'ryj)to- 

 zoon or with Archa-ozoon. It may, however, l)e regarded 

 as a possible survivor of an ancient type, probal)ly a ja-oto- 

 zoan, forming an unusually large antl complicated skele- 

 ton, sometimes a foot in diameter, and which may not 

 improbably have existed much earlier than the time of the 



