AND THE REPORT ON THE GEOLOGY OF VERMONT. 123 



communicated the manuscript of a paper entitled: "jS'otes on the geological structure of 

 western Vermont, etc.," read by him before the American Association at Albany in 1851. 

 In it he refers the reddish sandstone and shales, and reddish, Avhite and gray limestone 

 as a group " belonging to the period of the Oneida and Medina rocks, to which Mr. 

 Hitchcock now refers tham." 



1860 (July). Dr. Ebenezer Emmons, in the second edition of his Manual of Geol- 

 ogy Xew York, pul)lished during" the summer of 1860, in note A, page 280, calls atten- 

 tion to Professor Hall's remarks, in the Regents' Reports of New York for 1860, and 

 declares that the shaies referred to in northern Vermont, instead of being a new series 

 above the so-called Hudson River group, are really sub-silurian and of the same age 

 as the Paradoxides and Olenus jii-imordial zone of Bohemia. (See Manual of Geology, 

 page 87.) 



1860 (Oct.). "^^ Mr. Marcou made a communication on the black slate of Braintree, 

 Mass., containing Paradoxides, and on similar strata in ^Newfoundland, near Lake Cham- 

 plain and in the vicinity of Quebec," afterwai'ds given in detail in the paper entitled: 

 " On the Primordial Fauna and the Taconic system, by Joachim Barrande ; with adtli- 

 tional notes by Jules Marcou." (See Proceed. Boston Soc. Nat. History, Vol. vii, p)p. 

 357 and 369. Pul^lished November 23, and December 24, 1860.) On page 375, Mr. 

 Mai'cou uses for the first time the name slates of Georgia, and refers them to the Ta- 

 conic system of Emmons. 



1861 (Feb.). In the "Thirteenth Annual Report Regents University, New York," dated 

 on the title page 1860 (but the true date of publication is February, 1861), Prof. J. Hall 

 gives a new description of the three trilobites found at Georgia under another title: 

 "Note upon the trilobites of the shales of the Quebec group in the town of Georgia, 

 Vermont," pp. 113 to 119. We must remark, that the "title was changed in a pai't of 

 the edition, by substituting the words Quebec group for Hudson River group, in defer- 

 ence to the views advanced by the Geological Sm-vey of Canada." (See " Fifteenth 

 Annual Report Regents University, New York," page 196, Albany, 1862.) 



The author describes and figures the same three trilobites under new generic names : 

 Ba7'randia substituted for Olenus, and Patliynotus instead o^ Peltura or Olenus, making 

 two mistakes. First the genus Barrandia existed i^reviously for another form of trilo- 

 bites, having been proposed as far back as 1819 by McCoy (see Ann. Nat. Hist., 2nd 

 series, Vol. iv) ; and, second, the genus Batlryttot/ts had been anticipated for the same 

 fossil by Dr. Emmons, in 1860, who called it Pagara (see Manual of Geology, p. 80, 

 figs. 5, 7 and also p. 280). 



But the confusion does not stop here; for Mr. Hall proposed, in 1862, the name Olen- 

 ellus. Recognizing that the name of Barrandia was untenable, he "pi'oposes to return 

 to the name Olenellus''^ written on the manuscript, but changed to Barrandia at the mo- 

 ment of sending it to press. Now Professor Walcott justly refers the ElUptocepliala 

 asapJioides of Emmons, 1844, to the same genus as the Olenus Thompsoni; showing 

 that Emmons has priority, fii-st in calling the genus in 1844 ElUptocepliala and in 1855 

 EllijJtocephalns. If it is necessary to drop E lliptocephalus on account of its great sim- 

 ilarity with Ellipsocephalus of Zenker 1833, also a primordial genus, I think that Em- 

 mons' priority ought to be recalled in some way, and the name of the genus may be 

 Ebenezeria, in honor of Dr. Ebenezer Emmons and his Taconic system. 



