326 E. Billings on some of the 



" Mr. C. H. Hitchcock exhibited a geological map of Vermont, 

 and explained the principal features of the complicated geology 

 of that State. 



'' The two most interesting points in this connection were, that 

 there is no foundation for what Mr. Emmons called his Taconic 

 system, (a mixture of the Silurian and Devonian,) and that the 

 Dorset limestone (his Stockbridge limestone) is newer than the 

 lower Silurian, and is probably upper Silurian or Devonian. 



" Prof. W.B. Rogers remarked upon the importance of the inves- 

 tigations referred to by Mr. Hitchcock, and spoke of the difficulty 

 which the geologist has to encounter in attempting to ascertain the 

 precise sequence of the rocks in a region where, as in the greater 

 part of Vermont, perplexing structural features, metamorphic in- 

 fluences, and an extreme paucity of fossils combine to embarrass 

 his enquiries. It is not therefore matter of surprise that, in spite 

 of repeated explorations, some important problems in the geology 

 of the State should still remain unresolved. 



" As regards the belt of formations on the western side of the 

 State, extending along the shore of Lake Champlain, the abundance 

 of fossils and the almost undisturbed position of the strata have 

 rendered their investigation comparatively easy, so that these for- 

 mations were early identified with the lower members of the pale- 

 ozoic series, from the Potsdam sandstone to the Hudson River 

 group inclusive. Immediately eastward of this narrow strip is 

 another belt of variable breadth, extending through more than half 

 the length of the State, and passing northward into Canada. This 

 consists of reddish sandstone and shales, and reddish, white, and 

 gray limestones, which, from lithological peculiarities and the ab- 

 sence of distinct fossils, were much less easily referred to their pro- 

 per geological position. Indeed it is only within a few years that 

 this remarkable group of strata has been generally recognized as be- 

 longing to the period of the Oneida and Medina rocks, to which Mr. 

 Hitchcock now refers them. 



" As connected with the history of this investigation, Prof. Rog 

 ers felt some satisfaction in stating that in a paper entitled " Notes 

 on the Greological Structure of Western Vermont, &c.," communi- 

 cated by him to the American Association at Albany in 1851, the 

 manuscript of which he now submitted, he gave a detailed account 

 of numerous sections and longitudinal tracings made during prece- 

 ding seasons, and in express terms announced the conclusion that 



