146 NEW YORK STATE MUSEUM 



related paleozoics is at Northville, about 13 miles to the south,, 

 where the Potsdam appears, and near which the Calciferous i& 

 known. The Trenton is met about 5 miles still farther south,, 

 and the Utica a few miles beyond. This outlier is therefore not 

 so isolated as the Schroon lake exposure, which is 15 miles west 

 and 40 miles north of the nearest related outcrops; and the North 

 River exposure is even more remote from its own kind. 



The exposures at Wells were first recorded by Ebenezer Emmonsy 

 so far as the writer (J. F. K.) can discover. In the Geology of the 

 second district, p. 417, he says, while speaking of Hamilton county: 

 "At Hope I found a few acres of Trenton rock, loaded with the 

 usual fossils; and to the south a few miles, the Calciferous, each 

 in place. They form the extreme point of the Champlain group, 

 which comes up from the Mohawk valley through Northampton 

 and Mayfield." Though Prof. Emmons said Hope, he must have 

 meant Wells, as no outcrops occur at Hope. Prof. Hall has stated 

 to the writer that Vanuxem first discovered the Wells exposures, 

 in 1842, and this statement has been repeated by Darton, the 

 writer, and Ruedemann, but Vanuxem's report on the third dis- 

 trict makes no mention of the Wells outcrop, while Emmons does 

 in 1842, as above quoted. Hamilton county belonged in the sec- 

 ond district. Darton 1 gives some data regarding Wells and a 

 geologic cross-section, which is however somewhat assumed, as 

 a comparison with the detailed map here given will show. Mr 

 Darton had the large faults in mind, that run north and south, 

 and the details at Wells were somewhat incidental to a larger 

 theme. Rudolf Ruedemann has also given considerable attention 

 to the W r ells area in connection with his extremely significant and 

 interesting observations on the directions assumed by the grap- 

 tolites in the Utica slates^ which give a clue to the currents of 

 the Ordovican sea. 2 Dr Ruedemann describes the Wells outlier 

 as forming an oblong plain on whose sides the walls of gneiss rise 



i Darton, N. H., 13th an. rep't N. Y. state geologist. 1893. p. 415. Idem. 1896. 

 p. 47. 



2 Ruedemann, Rudolf. Evidence of current action in the Ordovician of New 

 York. American geologist. June 1897. In this paper Wells or Wellstowu, i» 

 merely referred to on the map. Additional note on the oceanic current in the- 

 Utica epoch. Idem. February 1898. p. 75. 



