No. 12. — Exploration of Lake Titicaca, by Alexander Agassiz 

 and S. W. Garman. 



II. Notice of the Palotozoic Fossils by Orville A. Derby, M. S. 

 With Notes by Alexander Agassiz. 



Sperifera camerata Morton. 



This well-known species occurs at Yampopata and the island of Titicaca. 

 The specimens are well preserved, and their identity with the North Ameri- 

 can and Brazilian forms cannot he doubted. Like some of the latter, they 

 show concentric lamellae like those represented by d'Orbigny on his S. con- 

 dor.* In my paper on the Brazilian Carboniferous Brachiopods I have 

 united with doubt S. condor with S. cmnerata. Mr. Agassiz's specimens, 

 which come from near d'Orbigny's locality, and are associated with the 

 same forms, appear to clearly establish their identity. As in North America, 

 this species enjoys a wide range. D'Orbigny and Salter f identified it from 

 various localities in the vicinity of Lake Titicaca. Toula % describes it as a 

 variety of S. striatus from Cochabamba on the eastern slope of the Andes, 

 and I found it in a specimen brought by Professor James Orton from the 

 Pichis River, Peru. 



Athyris subtilita Hall sp. 



This species occurs in the collection from Yampopata, d'Orbigny describes 

 it under the name Spirifer Roissyi from Yarbichambi, and Salter and Toula 

 have identified it from the Isthmus of Copacabana and Cochabamba. 



Rhynchonella sp. 



A species of this genus is represented by fragments on a slab from Yam- 

 popata, Though not sufficiently well preserved for positive identification, 

 there are reasons for believing it the same as the form figured by Salter from 

 Santa Cruz, and by Toula from Cochabamba as R. pleurodon Phillips. 

 This form is doubtfully identified by Meek and Toula with R. uta Marcou 

 (R. osagensis Swallow), to which it is certainly much more nearly allied than 

 to Phillips's species. A similar form occurs at the Pichis River locality, in 

 Peru. 



* "Voyage dans 1'Amerique Meridionale, Paleontologie, p. 46, PI. V. Fig. 11 - 14. 



t Quart. Jour. Geol. Soc, Vol. XVII. p. 50. 



t LIX. Bde. d. Sitzb. d. Kais. Akad. d. Wissensch. I. Abth., 1869. 



