490 Walter Keeping — Fossils from Central Wales. 



These branches are usually dendroid, but occasionally they anasto- 

 mose to form a network. 



Localities. — Waun Nantydd Valley, between Trawscoed and Llan- 

 trisant; above Taliessin ; in the Metalliferous Slates. 



Foraminifera. PL XI. Figs. 13-15. 



The Eev. J. F. Blake first detected these organisms in the slates 

 of Cwm Symlog, and published a note on their occurrence in the 

 Geol. Mag. 1876 (Dec. II. Vol. III. p. 134). Mr. Blake writes : "The 

 most perfect of these hollow casts could not be distinguished from 

 that of Dentalina communis, and I could venture to name other forms, 

 but with less certainty." Of these other forms I have succeeded in 

 finding better specimens, which prove them to belong to the genera 

 Botalia (?) and Textularia. They occur as minute ochreous spots 

 in thin pale slaty shales, either elongated {Dentalina) or rounded 

 (Botalia? and Textularia), On examining them with the lens, their 

 camerated structures are perfectly clearly seen, the chambers being 

 still hollow, and the original test, with the internal septal structures, 

 replaced by an oxide of iron. From six to eight chambers are seen 

 in the Botalia, fifteen in the Textularia, and from five to nine in the 

 Dentalina. The Dentalince are straight, or nearly so, but occasionally 

 curved ; their partitions are mostly oblique, but vary. Length from 

 1 mm. to 1^ mm. 



It is remarkable that these forms of the Foraminifera are undis- 

 tinguishable from our common living species. Mr. Blake has 

 pointed out the similarity of the Dentalina to the living D. communis; 

 the Botalia and Textularia are also identical with recent shells of 

 these genera. I therefore offer no new specific names for these 

 earliest known types of our ordinary Foraminifera.^ 



Annelida. 

 Myrianites Lapwortliii, n. sp. PI. XL Figs. 16, 17. 



A well-marked worm trail from Morben quarry, near Machynlleth. 

 Only three specimens are known, two of them being upon the same 

 slab of slate. They ai'e coiled in parallel transverse curved dupli- 

 catures, which gradually diminish in length up to an apex, so as to 

 produce that remarkable conoidal worm trail so well known in the 

 Lampeter species figured in Murchison's " Silurian System." 



The total breadth of the body is 5 or 5^ mm., consisting of an 

 axial groove or body proper, and the impressions of the lateral feet 

 on either side. The axial groove is a gentle depression, 2 mm. 

 broad, and well defined. It is simple, or only slightly sinuous 

 from the encroachments of the feet. Feet represented by gentle 

 semicircular or oval prominences, continuous (in contact with one 

 another), and alternating on the two sides of the body groove. Each 

 foot is well defined, measuring 2 mm. broad, and from 2 — 3^ mm. 

 in length. In some parts arched grooves cross the foot-markings 



^ Foraminifera occur also in the shales above the Bala Limestone at Guildfield, 

 near "Welshpool ; and Mr. Davies of Oswestry tells me of others at Glascoed, near 

 Llan y blodwell, Montgomeryshire. 



