74 0. M. DAWSON ON A NEW 8ri;CIE9 OF 



Bamo way corrospoiids very closely -with tho Tertiary and modern 

 Nuramiilitcs. 



In the arranj?ciTiont of tho ])illars uniting,' tho folds of the lamina, 

 the sponj?y inp;rowtli fiUin*; the chamhers, and in otlier points, this 

 LoffiisiahciiTH a strikiiifij rescmhlanco to some forms of f^fromatijmm. 

 It differs, however, in its regnlarly spiral cliaraeter, and in the fact 

 that no pores have been observed to traverse tho "primary" lamina. 

 It is scarcely probable, however, that tho orj^anie connexion between 

 tho different parts of tho Loftima was maintained only in directions 

 parallel to tho circuitous course of the lamina. 



Genus Lofiusia, Brady. 



LOPTUSIA COLUXniANA, sp. uov. 



Test oval ; circular in transverse section ; the ends rounded or 

 very obtusely spindlo-sha])cd ; cliambers man), narrow; septa very 

 oblique, more nearly parallel to tho sides of a cylinder tlian is the 

 primary lamina ; primary lamina and septa, or '• secondary " in- 

 fi;rowths, supported by pillars or '' tertiary " ingrowtlis ; j)illars nu- 

 merous, arranged in parallel linos transversely and longitudinally, 

 expanding laterally at their distal extremities to form imperfect cham- 

 bers, which are tilled with a loose, granular, cancellated growth. 

 Exterior of test frequently becoming irregular and acervuline. 

 Length of test about y-'j/Jy of an inch, width of test about y^yL of an 

 inch ; intervals between successive folds of tho adult primary lamina 

 about Y^,T of an inch. 



Carboniferous Limestone, Marble Canon, British Columbia* 



DESCRIPTION OP PLATE TI. 



Fig. 1 reprcponls portion of a tran?pnrpnt section, nearly at right angles to 

 the longer axis of iho Foraniinifcr. Tlio test is represented by the 

 darker wliading. wliile more transparent calcite fills the. cliambers. The 

 primary lamina is designated by a, and is seen to bo thickened by the 

 spongy ingrowth, h designates one of the more perfect secondary 

 growtiis or septa. IVIany of the tertiary ingrowths end proximally 

 before reaching the inner lamina ; this may arise in some cases from 

 the sliglit obliquity of the ))lane of section to the direction of their 

 axes. I'hat the section is not truly through tho centre of the form is 

 seen at d, where it becomes tangential to tho inner layer, and exhibits 

 a portion of the ni'imary lamina in pbm. (X 2.").) 



Fig. 2 is a portion of a longitudinal section of the outer part of the te.st. o 

 designates the primnry Inmina ; c tho tertiary processes or pillars, e, /, 

 & J refer to tho acervuline or irregular exterior portion, wellde\e- 

 loped in this specimen. At e an irregular tier of chambers has been 

 formed, which pass outwards in some pbices almost imperceptibly into 

 d, a spongy or cancellated mass, which is generally limited exter- 

 nally by a more or less definite wall, g. The secondary growths, or 

 septa, are not seen in this section, and this is very frequently the case 

 ill longitudinal sections. It arises partly from the greater transpa- 

 rency of these as compared with tiie thickened floors and the pillars, and 

 apparently partly also from the circumstance that they are in reality 

 more fragile. (X 2o.) 



Fig. 3 represents a portion of a longitudinal tangential section, which is very 

 instnictive, as showing nearly all parts of the test. This may profi- 



