4 EXPLANATION OF THE PLATES. 
c. Original. Large tubular cast, showing irregular deep corrugations, and 
finer wrinklings, separated by a longitudinal ridge. Collected by Mr. T. 
Mayne, and presented by him to the Geological Survey of Ireland 
From a compact bed of greenish grit, containing many mounds of 
Histioderma, discovered by Mr. T. D. Falkner in rocks, exposed at low 
water on the shore between the Brandy Hole and Periwinkle Rocks, 
Bray Point. 
CRUSTACEA(?)—-TRILOBITA. 
Fic. 5.—a, b. PALZopyGe Ramsayt, Salter. 
a. Enlarged to correspond with 5 6. From the chart of Fossil Crustacea by 
Messrs. J. W. Salter and H. Woodward, fig. 32. Locality not given. 
b. From the original figure in the Journal of the Geological Society, 1856, 
vol. xii., pl. iv., fig. 3. 
Callow Hill, Longmynd. 
With respect to this obscure fossil Mr. Salter observes :—‘‘ I do not very 
strenuously maintain it to be a Trilobite ; but it is either a caudal shield 
of one, or else a broad body segment of a phyllopod, allied to Hymeno- 
caris. I feel persuaded of its being a Crustacean, and hope to have 
further evidence when the description of the Longmynd district shall be 
ready.” M.G.S., vol. iii, p. 244. 
