378 Dr. Hunt on the Primordial Zone 



very few species in common. With these facts, even if it should 

 one day be proved that the fossils belong to the broken and 

 transported fragments of rock which enter into the conglomerate, 

 it will not be less true that the primordial and secondary faunas 

 must have belonged to separate formations in the region which 

 furnished the transported materials, for it is evident that if these 

 fossi] species had been orighially mingled in a common formation, 

 no physical cause could have assorted and separated them, so as 

 to form the two distinct groups which represent the primordial 

 and secondary faunas in the rocks at Point Levis. 



" II. We must also remark that if any admixture of the species 

 of the two faunas should ultimately be found in these conglomer- 

 ates near Quebec, it would in no wise prove that there had been 

 a similar commingling in the locality which had furnished the 

 boulders of these conglomerates, for the fact of their having been 

 transported, would of itself suffice to explain such an apparent 

 co-existence or confusion of the two faunas." 



In the fifth chapter Mr. Barrande discusses the Taconic system 

 of Dr. Emmons. This geologist, while engaged in the survey of 

 a part of the State of New York, recognized the existence of a 

 series of sedimentary rocks, which he regarded as qlder than 

 those supposed by his colleagues to represent the Silurian series. 

 A similar view had been maintained by Eaton, but was rejected by 

 most of the American geologists, who up to this time have re- 

 garded these Taconic rocks of Emmons as belonging to the Lower 

 Silurian series. In 1844 Dr. Emmons described certain fossils 

 from these rocks, which he supposed to be new and to distinguish 

 what he called the Taconic system, regarded by him as the true 

 palgeozoic base. In 1846 Mr. Barrande discovered in Bohemia, 

 beneath the horizon of the hitherto recognized Silurian fossils, a 

 new and extensive fauna in what he desio-nated the Primordial 

 Zone. The fossils described by Dr. Emmons consisted, besides some 

 imperfect trilobites, of a few graptolites, mistaken by him for 

 fucoids, and several very doubtful forms which are valueless for 

 the purpose of determination. According to Dr. Emmons this 

 system, which he divides into an upper and lower portion, has a 

 thickness of 30,000 feet, and extends throughout the whole Appala- 

 •chian chain. He has described it as composed in ascending order 

 of, 1st. Granular quartz; 2nd. The StoCkbridge limestone; 3rd. Mag- 

 nesian slates ; 4. Sparry limestone ; 5. Roofing slates (graptolitic) ; 

 6th. Silicious conglomerate ; Yth. Taconic slates ; 8. Black slates. 



