REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 rl47 



Hudson shales and schists 

 The Hudson shales of the Hudson valley are represented in 

 the metamorphic area of southeastern New York and western 

 New England by a thick series of slates and mica schists. 

 The transition from shale through slate to schist can be well 

 observed in traveling across Dutchess county from west to 

 east in the latitude of Poughkeepsie; and the term Hudson 

 schist has recently been adopted in place of the terms Manhat- 

 tan schist (of New York geologists) and Berkshire schist (em- 

 ployed by the United States geological survey workers in New 

 England). The Hudson formation is of little economic impor- 

 tance, though much schist has been employed in foundation and 

 retaining wall work on and near Manhattan island, and thin 

 layers of sandstone occurring in the shales have been worked 



in Dutchess county. 



Green Pond conglomerate 



The name Green Pond conglomerate was given by Darton in 

 1894 to a formation occurring on the borders of the Devonian 

 outlier noted on p. rl44. The principal exposures of this 

 formation, in the area here discussed, are west of Cornwall 

 station and in Pine hill near Highland Mills, both in Orange 

 county. The rock is a conglomerate consisting of white to pink- 

 ish quartz pebbles, embedded in a reddish silicious matrix. 

 Darton states that in this vicinity the formation is not over 60 

 feet thick. In stratigraphic position the Green Pond conglome- 

 rate, Pine Hill quartzite and Longwood red shales correspond 

 approximately to the Shawangunk grit of Ulster county, and to 

 the Medina (including Oneida) rocks of western New York. 



Pine Hill quartzite 



The name Pine Hill quartzite is here proposed for a series of 

 quartzite beds overlying the Green Pond conglomerate and un- 

 derlying the Longwood shales. The formation is well shown 

 in Pine hill, east of Highland Mills, Orange co. Transition 

 beds between the quartzite and conglomerate and between the 

 quartzite and shales occur; but in general the lithologic dis- 



