MIDDLE CAMBRIAN. 


Names and References; Observations, &c. 




20 
Sr oaae Reference to McCoy's 
Drawers. | Synopsis: and Figures of Genera. 
Gi Under Grapt. latus, p. 4. 
(Not the figure or description, 
which belongs to G. priodon, 
Pl. 18, fig. 7.) 
Gi 
Gi Cennnnannnnn eats) 
Gi 
Gi 
Gi Compound Graptolites, di- 

chotomously branched on one 
plane. 


Didymograpsus latus, Salter. The specimens 
to which I restrict the name are from 
Skiddaw slate localities, and are broken 
portions of a twin graptolite. The specific 
name may stand, as unoccupied. 
Didymograpsus, sp. very like D. latus, and 
possibly identical. 
Didymograpsus geminus, Hisinger (Leth. Suec. 
Supp. 2, pl. 38, fig. 3). It is a Stiper 
Stones species, also found at Whitesand Bay. 
Mem. Geol. Surv. Vol. 111. pl. 11 8, fig. 8. 
Didymograpsus V-fractus, Salter (Quart. Journ. 
Geol. Soc. XIx. p. 187, fig. 13 e), A species 
closely related to D. Pantoni, McCoy, from 
Australia. 
Didymograpsus Hirundo, Salter (Quart. Journ. 
Geol. Soc. x1x. p. 187, fig. 13f). D. constric- 
tus, Hall (Grapt. Quebec, pl. 1, fig. 23—27). 
Tetragrapsus bryonoides, Hall (Graptolithus, 
ib. pl. m1. 1v. vi). A Graptolite with 4 thick 
branches recurved. Quart. Journ. Geol. Soc. 
ib. fig. 8a. The genus is like Didymograp- 
sus, but twice branched. 
Tetragrapsus quadribrachiatus, sp. Hall (1. c. 
pl. 5). Zetr. crucialis, Salter (Quart. Journ. 
Geol. Soe. ib. fig. 8b). Quite a distinct spe- 
cies, with much longer and patent branches. 
Dichograpsus, Salter. A large branching Grap- 
tolite, first discovered in Canada by Sir W. 
E. Logan. 
Graptolites, excepting Dendrograpsus and 
Dictyonema. This is a more compound form 
of Graptolite than Tetragrapsus, the branches 
bifurecating again and again, but only in 
one plane. Moreover a horny disk connects 
the base of the branches in some specimens. 
It is the most compound of 

Numbers and Localities. 
Seaw Gill, Whiteless, a. 39, 
Knockmurton. 
Omit the Builth Bridge 
locality, which contains 
only the Graptolites prio- 
don, and is Wenlock shale. 
Upper Arenig, Whitesand 
Bay. (Dr. Hicks.) 
a. 38, Skiddaw Slate. 
(From Bryce Wright.) 
Skiddaw Slate. 
Skiddaw, Stiper Stones, 
Whitesand Bay, St. Da- 
vid’s. 
Skiddaw Slate. (From 
Bryce Wright.) 
a. 48, Skiddaw Slate. 
(From Bryce Wright.) 
