332 WALCOTT 



most important portions of Mr. Matthew's notes are copied in 

 full.^ 



About one hundred feet or more above the horizon where 

 Psammichnites appears, separated from it by a conglomerate, 

 indications of the Olenellus fauna show themselves. These 

 consist of Volborthella (a chambered cell resembling an Or- 

 thoceras), the cystidean genus Platysolem'ies, Pander, and a 

 large Obolus, allied to Michwitzia ( formerly Oboliis ? or Lin- 

 gula P) monilifera Linrs, of the Eophyton sandstone of Swe- 

 den and the upper part of the '• Blue Clay" of Russia. Some 

 of the layers in this part of the series abound in soft green 

 grains similar to the glauconite grains of the Cambrian rocks 

 in Russia. The paste enveloping them is red. 



I have remarked above that the Basal series affords indica- 

 tions of the fauna which accompanies the trilobite genus Olen- 

 ellus and its kindred genus Mcsoiiacis, but indications of a 

 similar fauna are also found in the two lowest bands of the St. 

 John group. (Loc. cit., p. 140.) 



In summing up the facts bearing on the comparative age of 

 this part of the Cambrian rocks in Acadia we get no aid from 

 the typical genera of this horizon, Olenellus and Mesonacis, but 

 the Acadian rocks contain other genera of this faunas which 

 serve to fix their age with a certain degree of accuracy. Some 

 of these genera, however, are such as may have a wider range 

 of existence in time than the trilobites, and, therefore, are not 

 of the same homotaxial value. The trilobites that do occur are 

 not so definitive as some others. (Loc. cit., p. 143.) 



In 1892 a section is given as ' Basal Series of Rocks or 

 Etcheminian Stage,' but no fossils are mentioned except as 

 faunas that occur in two divisions.^ 



In his admirable essay on the Protolenus fauna Mr. Matthew 

 mentions the occurrence of protozoans, brachiopods, echino- 

 derms? and moUusks, and worm furrows and trails in the Etche- 

 minian. He says : 



No fauna of trilobites has yet been found below this sand- 

 stone (at base of St. John Group). Here, then, should be drawn 

 the line between Cambrian and pre-Cambrian. ^ 



He states that the ' Protolenus ' fauna found above the 



' On Cambrian Organisms in Acadia : Trans. Roy. Soc. Canada, Vol. VII, 

 1889 (publi.shed 1890), p. 138. 



* List of Fossils : Bull. Nat. Hist. Soc. New Brunswick, No. X, p. 1. 



3 The Protolenus Fauna : Trans. New York Acad. Sci., Vol. XIV, 1895 series, 

 p. 103. 



