109 



radially disposed round this central [mint. It is to be regretted, ho\v.-\.-r, that, \\ith tin' im 

 perfect materials at my command, T am at present comp.-ii.-d t-> leave this and --ther points of 

 intere-t in the structure of thi- remarkable form unelucidated. 



,. Common in the Hamilt--n group, at liartlett'.- Mill.-. n 



Arkona, Township"!' Ho-am|uct. (Also common in the Hamilton Shale-. at < 'anand d-_'Ua. 

 v w fork. 



1:;:;. T.KMUI-UHA PKNMKCIKMI> (Nicholson). 



i 



i Nichol-on i. i, , Marrh. 1 - 



f'"lv/.oarv forming a linear flattened expansion, which prohahls divide- diohotomoiuly. 

 The total width df the frond is about two lines, and it.- thickm--- in the mid. He i- ah--ui tw..- 

 third- "fa line, gradually taperin- t" the mar-in. Both sides of the OOenoscium om-certainly. 

 and the other probablv) are furni>hfd with an exceedingly -tr.-ir_. Miint. me-ial. longitudinal 

 i'id_e "i- keel, the height of which is about a fourth of a line and it.- thicknes- about the 

 game. < )u either -id-- ol the central keel are four rows of cell< in alternating line-. 'I'li- 

 mouths of the cells are circular and prominent, ab ut live or >ix "ecn)iyinL r the -pace of 

 line mea-mvd longitudinally. Outside the rows of cells on either -i-le i- a plain m>n celluli 1 

 ous space, about one third of a line in width, by which the margin i- eon-tituted. 



In most of its e .-niial elnracters, T" ///ii<>/-<i penniformu iii^. II'H agreee with 7'. 

 hut if i- a much stron-er and more robust form, with a broader and more elevated keel, and 

 j,,, ------ n,_. ;l marginal non-poriferous area which appears to be wanting in the latter. I have 



onlv !'ra-ment- of the sj.ecies, and am unable to State anything 88 to it.- -en> ral form of -r. -\\th 

 or it- total dimensions. 



L-,.-,iI'itii 'in'/ l : ',rmnt'<n)i. -Hamilton Formation, IJartlett's Mills, ne; r Arkona, Township 

 of Bosanquet. 



' AUlNoPORA (Nicholson). 



Journal, Vol. XIV.. No. 2, and Ann-d- of Nat. lli-t., Feb. 1R7I.) 

 PolyEoary infundibnlifonn, oaloareous, and reticulated. The external layer ->f the oy- 

 atliiform iV-md i.- composed of regularly undulated flexuou.- bran. -h--- which ana-tomo.- ( - with 

 one an-'ther after the manner of a Retepora BO as to form a Beriee "f oval lene.-trul--- l-'.xt.- 

 riorlv. the branch- - are aii'_ r nlated or rarinate and are -inooth and lion cellnliferoii-. lir 

 nallv. cadi branch -iv--- origin to an enormoualj developed k---'l or vertical lamina, which cor 

 r- -pond- in direction with the branch and is directed inwards toward- the centre of the funnel 

 Thf inner lace of the branches tint- presents a series of narrow, elevated parallel ri-lje- --pa 



1 by ! | at the bottom of which tin- cell- ..pen to all appi-ir:!iii-e. The f." 



tru! -pen at the bottom of the-e grooves. l'i - however, appear in part- 



'roiid to I--- rendered \e-icular liv m- iJ in- of a series <' -areou- lannn.e \\hich e.-n 



:-'ther the - 

 -in. : ----ntiL'tioii- 



I n BOD 



al-o. the inner -nd- 

 .-! the n-L 



llerted I"J- llier 1 



coiitini: . 



membrane, -- that ih- 



i h 







. 





nii 

 frond 



. 



di-nl 

 inn 



tli- 

 i- CO! 



I'll- 

 in a!:. 



' . ^ 





' ranch, their 



, 



c! Iho 



Oil 





A- 



