- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
"Stromatolites found in Karagwe-Ankolean rocks on the Tanganyika-Uganda border occur in siliceous beds associated with cherty and ferruginous breccia without trace of calcareous material. Somewhat similar conditions prevail in beds of the Singo series of Uganda from which Collenia-type structures have been recorded. Little stratigraphical value can be ascribed to the structures, but they are significant in pointing to the replacement character of some fine-grained siliceous beds which may explain the scarcity of limestone in the pre-Cambrian sequence of Uganda."