DIASTROPHISM AND THE FORMATIVE PROCESSES 321 



In the northwestern portion of the state, where the Silurian strata 

 are present to aid in correlation, this critical time period is repre- 

 sented by an extensive unconformity, but there has been no folding 

 there. But that is distinctly west of the Taconic belt.^ Kiimmel 

 discusses the matter thus: 



Contrary to long-prevalent and apparently well-established belief, the 

 lower and middle portions of the Silurian system are not represented in New 

 Jersey. Their absence in this and adjoining regions is indicative of somewhat 

 widespread earth movements, unaccompanied in this region by folding, which 

 closed the period of deposition indicated by the Martinsburg sediments, or 

 possibly overlying beds afterward removed by erosion, and raised the region 

 above the zone of sedimentation. When deposition began again, late in 

 Silurian time, beds of coarse conglomerate were laid down 



This is the Shawangunk formation between which and the Martins- 

 burg shale there is a gap representing the upper part of the Ordovi- 

 cian and all of the Silurian below the Salina of the full New York 

 section, but there is no marked divergence of dip and strike where 

 the two formations outcrop in proximity.^ 



In general, throughout most of the Appalachian province the 

 youngest Ordovician (Richmond) beds are lacking, and an angular 

 discordance between the Ordovician and Silurian at many points 

 implies an emergence corresponding to the Taconic folding to the 

 northeast. Ulrich states that at this time the whole Appalachian 

 region was considerably elevated and the middle and eastern parts 

 of Appalachia itself most probably subjected to profound orogenic 

 movements.^ Dana in particular has urged the magnitude and 

 importance of this early mountain development. Because evi- 

 dences of this movement, which was so intense in New England and 

 New York, have been recognized over a much wider area, he 

 regarded the Taconic Range of western New York as only one in a 

 great Taconic system of mountains."* This great system lay entirely 



' Stuart Weller, "The Paleozoic Faunas of New Jersey," Geol. Survey of New 

 Jersey, Rept. on Paleontology, III (1902), 54. 



^ H. B. Kiimmel, "Geological Section of New Jersey," Jour. Geol., XVII (1909), 

 356-57- 



i E. O. Ulrich, "Revision of the Paleozoic System," Bull. Geol. Soc. Am., XXII 

 (191 1), 436-37- 



4 James D. Dana, Manual of Geology, 4th ed. (1895), pp. 531-32. 



