MIDDLE CAMBRIAN. 

Names and References; Observations, &e. 
Numbers and Localities. 


10 
Gace and Reference to McCoy’s 
olumn of = 2 
Drawers.| Synopsis: and Figures of Genera. 
Worm-tubes and burrows. 
Gh 
Phyllopod Crustacea, allied to 
Apus and Nebalia. 
G 
case and 
Gh 
Trilobites. 
Gh 
Gh 




ANNELIDA (The burrows are frequently called 
Fucoids, see note in Wenlock Group). 
| Scolecites (Irregular worm-burrows in the sandy 
silt, crossing each other at various angles. 
Such burrows, filled with the excreta of the 
(Salter, 

| worm, are common in all rocks. 
Quart. Geol. Journ. Vol. Iv. p. 223). 
Scolecoderma antiquissimum, Salter (Zrachy- 
derma in various works) is a common large 
worm-tube in the Hollybush sandstone, 
| which sandstone I have referred to the 
middle Lingula. flags. Scolecoderma is the 
tube itself, often membranous, of the worm. 
Cruziana semiplicata, Salter (Mem. Geol. Surv. 
ui. pl. 3). A curiously plaited tube, fur- 
rowed along the middle. The genus was 
very abundantly spread over the world in 
Cambrian times. It is rather an anomalous 
form. But the ridgy plaiting of the upper 
surface probably has reference to the double 
rows of lamelle covering the back of the 
short broad worm. 
CRUSTACEA. Phyllopoda. 
Hymenocaris vermicauda, Salter (Mem. Geol. 
Sury. Vol. 1. 1866, pl. 1, fig. 2, p. 293). A 
shrimp-like form, evidently allied to the 
living Nebalia and the Silurian Ceratiocaris. 
The carapace is ample and undivided. Body 
with 7 or 8? joints. Tail with 6 appendages. 
CRUSTACEA Trilobita. 
Agnostus trisectus, Salter, Decade 11, M.G.S. 
pl. 1, fig. 11. The centre tail-lobe is triple. 
Agnostus princeps, Salter (Decade 11, 1. ¢. figs. 
1—5) ; also Mem. Geol. Surv. Vol. m1. pl. 5, 
fig. 1a). (A. princeps, var. Salter, Mem. 
Geol. Surv. lc. pl. 5, fig. 16). A common 
Lingula flag species, with radiating strize to 
the limb of the head. 



[These must be obtained 
for the collection. ] 
[Near Bangor: Ffestiniog, 
Dolgelly, &c. common.] 
Hollybush sandstone, Mal- 
vern. (Presented by Dr. 
Grindrod.) 
[Common near Bangor. | 
a. 15, Borth harbour, 
Portmadoe. (Presented by 
Mr. Salter.) Top beds of 
the middle Lingula flag. 
a. 16 (Pres. by Mr. F. Ash). 
b.16 (Mr. D. Homfray). 
a. 22, Whiteleaved oak, 
Malvern. Black Shales. 
Carreg wen, Portmadoc. 
(Mr. Ash and Mr. Homfray.) 
a. 267, a. 268, Moel Gron, 
Upper Mawddach. (Mr. 
Plant, 1869.) 
