6o 



Cambrian 



purple shales among the lowest beds of the series : 

 A small bivalve crustacean Leperditia Solvensis and L. 

 Cambrensis.) two small Brachiopods, Lingulella ferru- 

 ginea and L. primceva. In a higher part of the series, 

 consisting chiefly of yellowish sandstones and gray shales, 

 he also found two sponges (Protospongia) and various 

 trilobites, Microdiscus sculptus, Conocoryphe Lyellii 

 and C. Solvensis, Paradoxides Harknessii, Plutonia 

 Sedgwickii, Agnostus Cambrensis, and a Pteropod 

 Theca antiqua. These rocks had previously been con- 



FIG. 14. 



Theca antiqua. 



Microdiscus sculptu?. 



Agnostus Cambrensis. 



Lingulella ferruginea Paradoxides Harknessii. Leperditia Cambrensis. 



Group of Cambrian Fossils. 



sidered unfossiliferous, and the discovery is important 

 as showing that in sediments so old there existed a 

 considerable development of life of the same general 

 type as that found in overlying Silurian strata. 



In Sutherlandshire, as already stated, red Cambrian 

 conglomerates lie on the Laurentian strata unconform- 



