Vol. 69.] PALEOZOIC ROCKS OP THE CAETLEV DISTRICT. 17 



•cheeks prolonged into spines, and the transverse furrows reach 

 the eyes. Until further specimens are discovered, it will be best to 

 leave it unidentified. 



(4) Pliacops-obtusicaudatas Beds. 



Several forms of Phacops (including Dahnanniles) occur in these 

 beds. In addition to the typical Ph. (D.) obtusicaudatus are the 

 following : — 



Phacops (Dalmannites ?) sp. 1. — A pygidium and imperfect 

 body-ring from north-east of ]Sarthwaite evidently belong to one 

 species; and, from the character of its ornamentation, a head from 

 the left bank of the Haw they probably belongs to the same form. 

 It is noticed here on account of the character of the tail, the border 

 of wbich is not entire. Each fused segment is prolonged into a 

 denticulate extremity, very marked in the case of the two anterior 

 segments, but obscure in the hinder segments. The axis and limb 

 are ornamented with rows of elongated tubercles, which, judging 

 from the cast, were short spines. A similar ornamentation is seen 

 on the body -ring. 



The form approaches Cryphaeus, wbich, according to J. W. 

 Salter's diagnosis, 1 differs from Dalmannites only in the character 

 of the tail. He later comments upon ' the folly of classifying 

 the Trilobites by such a character as the pattern of the tail.' 



It is interesting to note that Prof. E. Kayser 2 describes, under 

 the name of Thysanopyge argentina, a tail from Didymograptus- 

 bearing beds of South America, which carries somewhat similar 

 denticulate extensions, and, in addition, a long terminal mucro. 



Phacops (Dalmannites) sp. 2. — A form was recorded by me 3 from 

 the Obtusicaudatus Beds of Lakeland, under the name of Ph. towns 

 Wyatt-Edgell. This form is common at Narthwaite. I cannot 

 find the specimen of Ph. torvus of Wyatt-Edgcll which led me to 

 make this identification. The fossil recorded by that name in the 

 Museum of Practical Geology is a true obtusicaudatus. 



Discussion. 



Miss G. L. Elles drew attention to the unity of the Ashgillian 

 as regards its graptolitic facies ; she pointed out that its graptolitic 

 fauna, though in some respects of the nature of a passage-fauna 

 between the Bala on the one hand and the Llandovery on the other, 

 had some distinctive characters of its own. With the advent of 

 this fauna the many-branched Pleurograptus, Leptograptus, and the 

 large Diplograpti, so especially characteristic of the Bala, died 

 away ; while its upper limit was defined by the incoming of Mono- 

 grapti. She also suggested that parallelism with the classic areas 



1 ' Monogr. Brit. Trilob.' Palaeont. Soc. (1864) p. 15. 



2 Zeitschr. Deutsch. Geol. Gesellsch. vol. 1 (1898) p. 425. 



3 Geol. Mag. dec. 3, vol. ix (1892) p. 537. 



4 J. G. S. No. 273. c 



