^SO TRANS. ST. I.OUIS ACAD. SCIEXCE. 



of the Niagara dolomite, at a quarry just west of tiie "Jolly-cut 

 road," Hamilton, Out. This species is also found near Louis- 

 ville, Ky. 



Calyptograptus(?) radiatus, nov. sp. 



Plate 4. Fig. 3. 



Frond ellipsoid, but cyathiform in its growing state. Numerous 

 delicate branches, with two or three bifurcations, radiating from 

 a common radicle. Some of these touch or overlie each other,, 

 but they are quite unconnected. The texture is corneous, with 

 the surface striated and marked with minute depressions or pits,, 

 which indicate the former position of the cellule. These depres- 

 sions are about the fourth of a millimetre in diameter, with an 

 equal space between. The branches are about one-third of a mil- 

 limetre broad. The greatest diameter of the frond is less than 

 three centimetres. Fragments of this species so resemble species 

 of Callograptus that they could not be readily distinguished ; but 

 in no species of the latter genus is the conspicuous funnel-form 

 apparent. 



Formation and Locality. — This fossil occurs in the "cherty-beds''^ 

 of the Niagara dolomite at Hamilton, Ontario. 

 Genus RHIZOGRAPTUS. 



Gr. rhiza, a root; graplio, I write. 

 Genus Rhizograptus (Spencer). Can. Nat., vol. viii., No. S, 1S78. 



Frond flabellate, but cyathiform in its growing state ; bifur- 

 cating branches with dichotomous terminations ; stem terminat- 

 ing in a well-marked bulb ; branches (marked with striaj) more 

 or less reticulated and united, or overlaid, by others. 



This genus is established on account of its bulbous root, which,, 

 as yet, has been found in no other variety. The numerous 

 branches closely overlie each other, or are connected in the form 

 of a net-work, without transverse dissepiments. Fragments of 

 specimens belonging to this genus somewhat resemble species of 

 Calyptograptus^ but have a much more regularly netted appear- 

 ance, and the branches are much more delicate. 

 Rhizograptus bulbosus, nov. sp. 

 Plate 4. Fia:. 4. 

 Rhizograptus bulbosus (Spencer). Can. Nat., vol. viii., No. ?, 1S7S. 



The frond is cyathiform in growing state ; numerous bifurcat- 



