REPORT OP THE STATE PALEONTOLOGIST 1902 1177 



amount of material has been gathered by the senior author and 

 the species have been identified to furnish the faunal lists 

 accompanying this paper. One of the striking results of this 

 paleontologic work is the discovery that a large number of those 

 species heretofore considered to have been characteristic index 

 fossils of the various members of the Helderbergian group are 

 not confined to particular stages but range throughout two or 

 more members of the series. 



The senior author, Mr van Ingen, first became acquainted with 

 the region in 188S, and has visited it frequently since that date. 

 The junior author, Mr Clark, has been superintendent of mining 

 operations for the Newark Lime & Cement Co., for several 

 years, and in that capacity has had fine opportunities to study 

 the folding and faulting of the formations beneath the surface. 

 In many cases the underground observations, supplementing the 

 surface work, have enabled the authors to satisfactorily explain 

 difficult points which could not have been solved by observations 

 on the surface alone. 



The structure is in places so complicated by excessive folding 

 and faulting that it has been found necessary to prepare a large 

 scale map. This map, still in manuscript, with a scale of 100 

 feet to 1 inch is based on stadia survey with the stations gener- 

 ally less than 100 feet apart, and all outcrops are tied up to sta- 

 tions. In this way the construction of parallel cross sections 

 at frequent intervals will be facilitated, and reproduction of the 

 tectonic features of the region by a series of models will be 

 made possible. 



While both authors have been closely associated in the study 

 of the structural features, Mr van Ingen alone is responsible for 

 the paleontologic portion. The authors wish to acknowledge 

 their indebtedness to Mr Calvin Tomkins, president of the New- 

 ark Lime & Cement Co., for many favors extended them during 

 the progress of their investigations. 



The visitor who approaches Rondout by boat on the Hudson 

 river has his attention attracted by a prominent hill which rises 

 steeply back of the lower town to hights of 250 to 300 feet. This 

 is the Vlightberg and the steep cliffs on the side fronting the 

 river are largely due to the quarries opened along the beds of 



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