NO. 3 MIDDLE CAMBRIAN FOSSILS FROM IDAHO— RESSER 3 



The shale has the species Hsted below. Besides the names given in 

 this list there is a poor specimen that seems to be Eocystites. A few 

 imperfect specimens of Obolus and a fragment of a shell similar to 

 Westonia clla represent the brachiopods. 



Elrathia sampsoni Resser Margaretia angustata Resser 



Elrathia longiceps Resser Schistometopiis typicalis Resser 



Glossoplcura mtcrmcdia Resser Urotheca sampsoni Resser 

 Hyolithcs idahocnsis Resser 



Lakeviczv limestone. — ^Where unaltered, two rock types characterize 

 this conspicuous and commercially valuable formation. One type con- 

 sists of clifF-forming massive beds which vary from nearly pure lime- 

 stone to nearly pure dolomite. The other beds are shaly, containing 

 thin-bedded, highly fossiliferous limestone. Sampson does not state 

 what relative position the two types hold with respect to each other, 

 but the thin-bedded and shaly material probably forms the lower por- 

 tion of the formation. Metamorphism caused different degrees of 

 alteration, some of the beds becoming a crystalline marble. 



Black crystalline limestone from the shaly beds yields an abundant 

 fauna which is listed below. 



Acrothcle spcciosa Resser Clavaspidella minor Resser 



Acrotreta nit ens Resser Elrathia idahoensis Resser 



Agnostiis bonnercnsis Resser Iphidclla cf. pannula (White) 



Alokistocare nodulijcrnm Resser Lingidclla idahocnsis Resser 



Alokistocare natalc Resser Pagctia fossula Resser 



Alokistocare nactum Resser Oryctocephalus walcotti Resser 



Alokistocare notatum Resser Utia curio Walcott 



Alokistocare normale Resser Zacanfhoides sampsoni Resser 

 Alokistocare nothum Resser 



A small collection of altered rock, presumably from the Lakeview 

 formation, contains a pygidium of Glossoplcura. Another lot of im- 

 pure dark blue limestone is especially interesting because it contains, 

 among other fossils, a species of Tonkinella, unfortunately too poorly 

 preserved to illustrate. This is not the Tonkinella-Vike. form described 

 below as the pygidium possibly belonging to Utia. 



RELATIONSHIP OF THE FAUNAS 



It has already been pointed out that the faunas of the Rennie shale, 

 both in the limestone nodules and in the shale, have no species in com- 

 mon. Nevertheless, both must be regarded as one fauna, since else- 

 where they occur together. Neither have any species been found com- 

 mon between the Rennie shale and the Lakeview limestone. These 

 faunas also are elsewhere found intermins:led. From these facts it 



