The Quarterly journal of the Geological Society of London . ^ are fully-^^ inch (25 mm.) long, and are slightlyrefiexed in every case except two nearthe distal end, which are directed out--wards and upwards. Some appear to bein pairs, but whether this is really thecase, or the result of a process of exfolia-tion during preservation, I am not pre-pared to say, though I incline to theformer view. The thecse seem to be more closelyset than Nicholson believed ; he reckonstwelve to the inch (five in 10 mm.), butthere are certainly six and probably seventhec« on each side in some specimens,and no sp
The Quarterly journal of the Geological Society of London . ^ are fully-^^ inch (25 mm.) long, and are slightlyrefiexed in every case except two nearthe distal end, which are directed out--wards and upwards. Some appear to bein pairs, but whether this is really thecase, or the result of a process of exfolia-tion during preservation, I am not pre-pared to say, though I incline to theformer view. The thecse seem to be more closelyset than Nicholson believed ; he reckonstwelve to the inch (five in 10 mm.), butthere are certainly six and probably seventhec« on each side in some specimens,and no specimen much exceeds | inch inlength (nine to eleven in 10 mm.).Every theca seems to have been furnished with a spine. The species seems to be most closely related to Glossograptusciliatiis, Emm., from which it differs (1) in its smaller size; (2)in the greater length of the spines. Occurrence.—EUergill Beds = Upper Skiddaw Slates. Locality.—Thornship Beck,. [X5.] Genus Trigonograptus, Nich. (a) Tkigofogeaptus ektsifoemis (Hall). (Fig. 34, p. 524.) 1865. BetioUfes ensiformis, Hall, Grapt. of the Quebec Group, Geol. , dec. 2, p. 114 & pi. xiv, figs. 1-5. 1875. Trigonograptus ensiformis, Hopk. & Lapw. Quart. Journ. Geol. xxxi, p. 659 & pi. xxxiv, figs. 8 a-c. 1890. Trigonograptus ensiformis, H. 0. Nich. Geol. Mag. dec. 3, vol. vii pp 340-341, figs. 1 & 2. -^ ^ There are two specimens in the Woodwardian Museum whichseem to be referable to this species, and I have also seen one inProf. Nicholsons collection. According to Hall, the species has a maximum length of 2| inches 524 MISS G. L. ELLES ON THE GEAPTOLITE [Aug. 1898, (63 mm.), and a maximum width of i inch (4-2 mm.), while otherspecimens | inch (12-7 mm.) long and -i^- inch (1-26 mm.) wideare also met with. There is a subsequent diminution ia widthnear the distal end : this is shown in Prof. Nicholsons specimen,figured in Geol. Mag. 1890. The best spec
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