4-0 NEW YORK STATE MUSEUM 



ist Dist. 1839. P- I 5 1 ]- Later his views are quoted and dis- 

 cussed by Mather. 1 Prof. W. B. D wight 2 has studied the region, 

 specially the locality of the Townsend iron mine, to which refer- 

 ence will be made later. N. H. Darton, 3 > 4 in two papers, has 

 given in detail some of the features of this area, and specially a 

 good account of the New Scotland (=Delthyris shaly) fauna. 

 Dr H. Ries 5 and E. C. Eckel, 6 have also briefly discussed the 

 region. Recently Kummel and Weller 7 have published a section 

 of the formations exposed in the cut near Cornwall station. 



The work to which this paper relates was taken up, partly with 

 a view to the determination of interesting,- though unexplained, 

 conditions of overlap or faulting which had been noted by pre- 

 vious writers, and partly for the study of some of the Upper 

 Siluric strata of whose age here as in other sections of the State 

 there has been ground for some uncertainty. In carrying on 

 this work the writer has had the advantage of suggestions and 

 advice from Dr A. W. Grabau of Columbia University. To Dr 

 C. P. Berkey, also of Columbia, are due thanks for assistance in 

 the determination of field measurements and structural features. 



Structure of the syncline. In the cut of the Ontario and West- 

 ern Railroad, the syncline can be best observed. Here the dis- 

 tance between the top of the Shawangunk conglomerate as 

 developed in the two limbs of the syncline is less than 500 yards. 

 In the east cut the dip does not vary more than 2° from the ver- 

 tical and the strike is n. 9 e., while in the west cut the dip is 

 75 s. e. and the strike is n. 40 e. The strike of the rocks as thus 

 measured in this cut indicates a rapidly spreading syncline. In 

 following along the strike of the outcrops, for yi mile, it is found 

 that the limbs of the syncline are 2 /z mile apart and that, with 

 the exception of some local changes where faulting has occurred 

 and to which reference will be made later, the dip of the rocks 

 has varied little from that observed in the railroad cut. From 

 the nature of the fold, the rocks as shown in the cut can extend 

 but a short distance to the northeast. The topographic relations 

 indicate that they soon fail and the underlying rock is the " Hud- 

 son River " shale. 



To the southwest, after about a mile, the formations of the 

 syncline as exposed in the cut disappear in the low swampy 

 ground. At about the point where the lower formations fail, 



1 Geol. N. Y. ist Dist. 1843. p. 351, 362, 400. 



2Vassar Brothers Inst. Trans. 1883-84. 2:74. 



'Am. Jour. Sci. 1886. 31:209-16 



4 Geol. Soc. Am. Bui. 1894- 5:379-80. 



*N. Y. State Geol. 15th An. Rep't. 1898. p. 426-28. 



6 N. Y. State Geol. An. Rep't. 1900. p. ri47-49- 



7N. J. State Geol. An Rep't, 1901. 1902. p. 17. 



