426 ME. P. LAKE ON TEILOBITES COLLECTED [Aug. 1906? 



^ The specimens occur in a light-coloured friable sandstone. 

 Trinucleus is confined to the Ordovician System, while Symphysurus 

 is limited to the Tremadoc and Arenig Series. The sandstone is, 

 therefore, probably of Arenig age. Both species occur in the same 

 blocks ; and it may be observed that Trinucleus boliviensis resembles 

 Tr. coscinorhinus, Ang., which seems to be the only species of 

 Trinucleus in Sweden that extends downwards into beds with 

 Symphysurus. 



(3) Right bank of the River Caca, between the mouth of the River 

 Challana and that of the Coroico, Province of Caupolican. 



Ogycjia sp. 



The only trilobites from this locality being fragments of Ogygia, 

 all that it is possible to say is that the beds are Ordovician, and 

 probably belong to the lower part of that system. 



(4) Nodules found lying loose on the ground, on the track from 

 Apolo to San Jose de Chupiamonas, rather more than 3 miles 

 north-north-east of Apolo, Province of Caupolican. 



Phacops cf. arbuteus, Lake ; Dalmanites Paituna, Hartt & 

 Rathbun (?) ; and D. Maecuriia, J. M. Clarke (?). 



Phacops arbuteus occurs in the Bokkeveld Beds of Cape Colony ; 

 Dalmanites Paituna and D. Maecurua in the Devonian strata of 

 Brazil. The nodules are, therefore, clearly of Devonian age, and 

 probably belong to the Lower Devonian. 



(5) Pound by Mr. John Turle on the Puerto-Mapiri and Aten 

 road, between Achicheri and Aten (probably near the River Yuyo), 

 on the borders of the provinces of Caupolican and Muiiecas. 



Dalmanites sp. 



Only a single broken specimen was obtained from this locality. 

 It appears to be allied to Dalmanites Maecurua, Clarke, or to 

 D. ClarJcei, TJlrich ; and the beds are probably Devonian. 



Desceiption of the Species. 



Peltuea sp. (PL XL, fig. 1.) 



gl'Two specimens of the thorax of this form have been found in 

 pale-violet or purple shale from above Pata. The more perfect 

 shows twelve segments ; the axis is broad, forming about one-third 

 of the total width, and there are slight indications of a median 

 tubercle on some of the rings ; the pleurae are horizontal, at right 

 angles to the axis, deeply grooved, obliquely truncate, and produced 

 into very short points. 



On the same specimen the outline of the free cheek is also partly 

 visible. It was crescentic, with the genal angles completely 

 rounded, and the eye placed far forward. 



