418 J. D. Dana — Brief history of Taconic ideas. 



were not formally claimed as Upper Taconic by Professor 

 Emmons, they have passed as such. His Manual of Geology, 

 the preface of which bears the date May 1, 1859, contains a 

 good figure of a large trilobite under the name Paradoxides 

 brachycephalus* which (as first suggested by Professor 

 C. H. Hitchcock in 186 If and is recently recognized by 

 Mr. Walcott)J is identical with Hall's Olenus Thompsoni ; 

 and it was evidently so named before the publication of Prof. 

 Hall's paper, though whether published before is not certain. 

 Unfortunately, Professor Emmons failed to mention the local- 

 ity of his specimen. On page 87, he makes the following judi- 

 cious remark : " According to Barrande, the Paradoxides and 



from the geological structure of the country, that these rocks all consist of strata 

 lying between the base of the Silurian and the beginning of the Coal-measures." 



On page 94, in a note, occurs the statement — of historical interest and therefore 

 here cited — that staurolite and some other minerals " mark with the same unerring 

 certainty the geological relations of this rock [a mica schist passing through cen- 

 tral New England] as the presence of Pentamerus oblongus. P. galeatvs. Spirifer 

 Niagarensis, S. macropleura, and their respectively associated fossils, do the rela- 

 tions of the several rocks in which they occur.',' ft was a valuable suggestion at 

 the time, but one that the establishment of the facts just cited irom p. 83 has now 

 set aside. 



In 1857, two years before the publication of Yol. Ill of the N. T. Paleontology, 

 cited from above, Professor Hall delivered an address before the American Asso- 

 ciation at Montreal. The writer was absent and never learned anything about its 

 contents; it was never published. In 1882. only six years since, appeared a 

 pamphlet, of forty pages, entitled " Contributions to the Geological History of the 

 American Continent. The Address of the retiring President delivered before the 

 first Montreal Meeting of the American Association for the Advancement of 

 Science, August, 1857, by James Hall." A note to the title is appended in 

 which the author says: "The original manuscript of his Address" "has been 

 copied without any supervision by him or any changes suggested by him." This 

 publication of the Address cannot claim to have historical value and hence 

 demands no notice here; for it came out iwenty-five years after date. It has no 

 scientific importance ; for the subjects presented are much more fully and more sat- 

 isfactorily discussed in the 96 quarto pages of the valuable Introduction to Vol. Ill, 

 above mentioned, all of which is Professor Hall's, and besides is two years later 

 than the Address. In the Appendix to this pamphlet on p. 68, it is stated that 

 "the Address has been facetiously criticised as proposing a system of mountain- 

 making with the [origin of* the] mountains left out " Accordingly, the Address, 

 although it had never been published, had on one subject been ." facetiously criti- 

 cised." The critical remark referred to occurred in volume xlii (1866. p. 210) of 

 this Journal, in a note on views published by Professor Hall in his Volume III, as 

 is stated in the note, and had no reference to the unpublished and wholly un- 

 known Address. Some officious friend has made a slip here: Professor Hall 

 could not have so forgotten himself. The pamphlet closes, following this, with 

 two pages of " Notes on Professor James Hall's Address by T. Sterry Hunt." 



* Manual of Geology by E. Emmons, 290 pp. 8vo. Philadelphia, 1 860 ; see p. 88. 

 Also C. D. Walcott on Cambrian Faunas. 2d paper, Bull. No. 30, U. S. G. S., 1886. 

 p. 167. The name Paradoxides asaphoides is given by Professor Emmons for the 

 figure on page 87. as if his first intention was to have inserted his old figure of 

 Elliptocephalv.s asaphoides, but afterward decided to insert a figure of the new 

 species. The name P. brachycephalus is changed to P. macrocephalus in a second 

 issue of the Manual (1860), both under the cut on page 88 and in a note to page 

 280, and the corrected name is cited by Mr. Walcott. 



f Rep. Geol. Vermont, p. 367. 



t Bull. U. S. G. S., No. 30. 



