90 



BEPOKT — 1884. 



3. Ajif i/chopsis Ltipworfhi, H. Woodward, 1872. 'Sixth Report on 

 Fossil Crustacea,' in 'Report Brit. Assoc, for 1872, 1873,' p. 323; 

 ' Geol. Mag.' vol ix. 1872, p. oC5 ; ' Quart. Jour. Geol. Soc' vol. 

 xxxiv. 1878, p. 331. 



This Phyllopod shield was also briefly described by Dr. H. Woodward 

 at the same time and in the same Report with the foregoiii]^. It is oval, 

 8 lines lon<^ by 7 broad (1 lino = ,'.j inch). It is concentrically striate in 

 most of the examples preserved, and in one case it retiiiiis the cephalic 

 plate. The best specimen has this plate in place, but 1li(! several >arts 

 and tho edges of the notch have been slif^htly damaged and disturbed by 

 pressure, so that its angularity is somewhat modified. This is from tho 

 Birkhill Shales in Eldinhopc Burn on (ho Yarrow, Selkii-kshire. This 

 division of the upper part of the Moffat 81iales ' is regatded as equivalent 

 to the lower part of tho Middle Silurian (Lower Llandovery). Another 

 specimen in the British Museum is from the Birkhill Shales at Sund- 

 hope Burn, in tho same neighbourhood, and another from the (Jrieston 

 Shales of tho Gala Croup, at Inverleithen, above the Moffat Croup, and 

 equivalent to the upper part of tho Middle Silurian. A good specimen 

 measures 17 mm. long by 14 mm. broad. Another appears to have been 

 23 mm. long by 18 mm. wide. The angle of the nuchal suture may have 

 been about 50°. 



A specimen of Apfi/cJiopsiii very similar to, if not identical with, 

 Aptychojisis Lajnvorthi, is in the University ^Museum, Cambridge, from 

 the Lower- Wenlock beds of Rebecca Kill, Ulverstone. It is 'abelled 

 ' Peltocaris anatina, Salter,* and is referred to under that name in the 

 ' Catal. Cambridge Fossils, &c.,' 1873, p. 03. Tho frontal notch is 

 angular, the median sutural lino is raised along the depressed shield, and 

 concentric striae are present. 



In another specimen in the same Museum, the test has been narrowed 

 by latei-al pressure, acting obliquely across the long axis of tho shield, as 

 is indicated by imperfect cleavage-planes crossing tho modified test at 

 an angle of about G0°. The frontal notch has been narrowed, its sides 

 made unequal, and its apex somewhat rounded. 



This specimen is from Skelgill Beck ; collected by Mr. Marr, F.G.S. 



What seems to be a similar example of a modified Aptychopsis, 

 squeezed into an even naiTower and more lanceolate shape, has been 

 figured by Mr. James Dairon in tho ' Transactions of the Geological 

 Society of Glasgow,' vol. vii. pi. 7, fig. 3."), and referred to in tho 

 Explanation of tho plate as ' Dtscinocaris Browniana, var. ovalis, Dairon.' 



All the little Phyllopod tests figured in this plate 7 are termed 

 * Discinocaris Dnnrnitma ' by Mr. Dairon ; but they appear to belong to 

 other genera. Fig. 20 looks like Peltocans aiitychoidcs. Figs. 31 and 

 34 are round shields of probably A. glabra, H.W. Fig. 8.5 seems to bo 

 a specimen of either A. Lapwortki or A. glabra much narrowed by 

 pressure ; but it may be otherwise. Figure 32 is a discoidal Aptyclwimny 



• The classification of the successive formations in tho Mofr'at district and vicinity 

 has been worked out by i'rofessor Lapworth, •^o (ivot. Mag. vol. ix. 1874, jip. n:};j-53(5; 

 Quart. Jour, Geol. Soc. vol. xxxiv. 1878, pp. 240-.34(i ; and Proceed. Jielfant i\at. 

 Field- Club, ser. 2, vol. i. part 4, Appendix IV. 1878; also Cntal. Wcxtcrn-Scottiik 

 Fossils, by Armstronjj, Younpr, and Robertson, 1876, p. 24. Although numerous 

 Phyllopod shields have been met with, no Goniatites have been recorded from these 

 beds. 



