APPENDIX B 



Fossil Determinations 



A pew fossil collections were gathered in order that age determinations 

 might be made. With the following identifications I have included a few 

 fossils (I and II) collected by W. E. Eumbold and put into my hands in 

 1907. The Silurian is from a Bolivian locality south of La Paz but in the 

 great belt of shales, slates, and schists which forms one of the oldest sedi- 

 mentary series in the Eastern Andes of Peru as well as Bolivia. "While 

 no fossils were found in this series in Peru the rocks are provisionally 

 referred to the Silurian. Fossil-bearing Carboniferous overlies them but 

 no other indication of their age was obtained save their general position in 

 the belt of schists already mentioned. I am indebted to Professor Charles 

 Schuchert of Yale University for the following determinations. 



I. Silurian 



San Roque Mine, southwest slope of Santa Vela Cruz, Canton Ichocu, Prov- 

 ince Inquisivi, Bolivia. 



Sent by William R. Rumbold in 1907. 



Climacograptusf 



Pholidops trombetana Clarke? 



Chonetes striatellus (Dalman). 



Atrypa marginalis (Dalman) ? 



Coelospira n. sp. 



Ctenodonta, 2 or more species. 



Hyolithes. 



Klcedenia. 



Calymenef 



Dalmanites, a large species with a terminal tail spine. 



Acidaspis. 

 These fossils indicate unmistakably Silurian and probably Middle Silurian. 

 As all are from blue-black shales, brachiopods are the rarer fossils, while bivalves 

 and trilobites are the common forms. The faunal aspect does not suggest relation- 

 ship with that of Brazil as described by J. M. Clarke and not at all with that of 

 North America. I believe this is the first time that Silurian fossils have been 

 discovered in the high Andes. 



II. Lower Devonian 



Near north end of Lake Titicaca. 



Leptocoslia fiabellites (Conrad), very common. 

 Atrypa reticularis (Linnaeus) ? 



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