﻿I860.] 



SALTER BOLIVIAN FOSSILS. 



67 



Peoetus, sp. (a fragment). Such fragments are common both in 

 Upper Silurian and Devonian rocks. 

 Locality. Same mountain (16,000 feet). 



[Beytiichia Eorbesii, Jones, n. sp. PI, IV. fig. 13 a, b, c, nat. size 

 and magnified. 



Carapace-valves oblong-ovate ; straight on the dorsal and obliquely 

 curved on the ventral edge ; obtusely tapering at one end, obliquely 

 truncate at the other ; bordered below and at the ends with a slight 

 rim : surface raised into four, equidistant, unequal, transverse, 

 rounded ridges ; the one next to the narrow end of the valve lowest 

 and shortest, the next one highest and longest of all. 



This is nearly allied to Beyrichia Bussacensis from the Lower 

 Silurian rocks of Portugal (Quart. Journ. Geol. Soc. vol. ix. pp. 141, 

 160, pi. 7. figs. 5 & 6) ; but it is narrower, and its ridges are 

 differently proportioned. It also approaches in form to the figure of 

 a Beyrichia that has been published, (without description) by Prof 

 E. Emmons among some Silurian Eossils of North America in his 

 < Manual of Geology,' 2nd edit. 1860, p. 100, fig. 90. 



This little fossil is seen in some numbers (together with Tentacu- 

 lites) on a small piece of dark-grey calcareous schist from the 

 western slope of Ulampu in the Bolivian Andes. It is dedicated to 

 its adventurous discoverer, Mr. David Eorbes. — T. It. J.] 



Tentaculites sueremtts, n. sp. PI. IV. fig. 11. 



Nearly an inch long, diameter 2 lines/ cylindrical, slowly tapering 

 until near the apex ; marked at intervals of about a line by cord-like 

 ridges, strongly projecting, and often in pairs. Between these are 

 close concentric annuli, or fine ridges, about thirteen in the space of 

 a line. 



The strong double ridges which ornament this species occur chiefly 

 on specimens which have the rings more distant than others. They 

 remind one much of the Tentaculites in the Wenlock strata of the 

 Isle of Gothland. I believe this species to be a new one ; it is a 

 good deal like T. ornatus, Sow. 



Locality. On the snowy ridge of Illampu, in company with Ho- 

 mahnotus Linares. A Ctenodonta and a Cup-coral are found with 

 them. 



Tentaculites Salenzii, n. sp. PI. IV. fig. 12. 



Tapering more rapidly than the last, and marked by numerous 

 equidistant rounded rings [with no intermediate annuli?]. The 

 want of annular striae may be only a comparative character ; but the 

 regularity of the somewhat oblique rings seems to be specific. 



Locality. It occurs in the grey shaly beds between the grits of 

 Illampu, and is dedicated (by Mr. Eorbes's request) to Senor Saienz, 

 whose kind and efficient help was of great service to him in his 

 explorations. 



Smaller Tentaculites (fig. 13 a) occur in some of the slabs with the 



e2 



