128 JULES MARCOU ON THE TACONIC OF GEORGIA 



1. Atops trilineatus is one of the first primordial fossils described, in 1844, by Dr. 

 Emmons, as a new species and a new genus. Prof. James Hall identified it with Caly- 

 mene Beddi, in 184:7, supjjressing at the same time the genus and the species. He was 

 followed in his determination by Messrs. Fitch (1849) and Walcott (1879). In 18G1, 

 Barrande accepted the view of Emmons, recognizing characters special to the trilobites 

 of the j^rimordial fauna, and he opposed Hall's identification with Calymene BecMi. 



Mr. Ford in 1871, 1873 and 1880 regarded this trilobite as a Conocephalus or Conoce- 

 phalites or Conocoryplie, consequently as a true primordial fossil. 



Finally, Mr. Walcott, retracting his first view of 1879, considers it as a Ptyclioparia, 

 a sort of S3aion}an of Conoceplialites and also a primordial genus. I may add, that 

 Professor Walcott noAV thinks the fossil is not a Ptyclioparia {ConocephalUes) . 



I have always thought that Dr. Emmons Avas right in making it a new type having 

 many affinities with the genus Sao, and I have, ever since 1860, used the fossil under 

 the name of Aiops trilineatus and as a characteristic primordial American fossil. From 

 the primitive Taconic region of the vicinity of Troy and in Washington County, New 

 York, it has also been found, first in 18G7 at Swanton, Yermont, and afterward at Bic 

 Harbor on the St. Lawrence opposite the Saguenaw river, Canada. 



All the different generic names given after that of Emmons are very unfortunate and 

 in direct violation of the law of priority. Aiops is a good name which ought to be re- 

 tained. The fossil is not a Conoceplialites, and even if it were, Atojjs has priority over 

 Ptychojyaria hy three years, for Corda did not create that genus until 1817, while Em- 

 mons' figure and descrijition dated from 1814. 



2. PJlliptocej)hala asajihoides, another of the very fcAv primordial fossils, first found 

 and described by Emmons, is also a good species and a good genus. As I have said 

 already. Prof. J. Hall made unnecessary new names Barrandia and Olenellas which 

 created confusion Avithout any apology for it ; for the name Paradoxides, used by both 

 Emmons and Barrande, was sufficient to characterize the fossil until a good and ajjpro- 

 priate name could be chosen to replace Elliptocephalus if necessary.^ Ehenezeria may 

 be used noAV, in honor of the discoverer of the Taconic system; but, like Dr. Ebenezer 

 Emmons, I think that it Avill be best and in accordance Avith priority to retain Ellipto- 

 cephalus. 



3. Protypns Ilitchcochi, first referred by Mr. "WTutfield to the genus Angelina, is 

 made the foundation of a new genus by Mr. Walcott. That creation seems unnecessary, 

 for the tAVO fossils referred to Protypus belong to the genus Ellijisocejjhalus, Zenker, 

 1833, a Primordial trilobitic type of Bohemia, Avhich those two fossils represent in the 

 NcAV World. 



4. Microdiscus quadricostatus, published and established in 1855, is another good 

 creation of Dr. Emmons, rightly referred by him to the Taconic system. The supposi- 

 tion, that it came from the Lorraine shales of Augusta county, Yirginia, and is a 

 Trinucleus, is, on the part of Professor Walcott, conjectural, and it maj^ lead to curious 

 confusion if accepted Avithout very clear and unquestionable facts. It Avould have been 

 strange if Dr. Emmons, always so successful in his classifications and paleontology of 



' " The genus Ellipsocephalns was uiikiiowii to me at the to retain it for the present" (see Emmons' Aiitcrirau Geol. 

 time of tlie publication of ElUptucephahia ; the name, from Vol. i, Part ii, p. 114, 1855). 

 its similarity, is uo doubt objectionable, but I am disposed 



