GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 4I 



The map represents the quartzite slope, with the break to the 

 southeast of it passing into the limestone southwest of the Maddock 

 farmhouse. Northeast of that point it shows the gneiss against the 

 limestone for a distance as indicating the tendency of the thrust, 

 and then against the quartzite, with a probable break between the 

 quartzite and the limestone. 



There are no traces of the quartzite south of Fishkill Village in 

 the valley of Clove creek, nor along the northwestern base of the 

 Honness spur. Along the northwestern base of Mount Honness 

 proper the gneiss is only 50 or 100 feet from the limestone, from 

 which it rises in bold ledges. The quartzite may once have covered 

 a portion of the northwestern slope of this spur. 



East of Honness, about one-third of a mile south of Johnsville, 

 the compact quartzite with some conglomerate outcrops for a short 

 distance in the woods at the base of the scarp, but is soon lost 

 beneath the kames which rest against the cliff. South of these 

 kames on the farm of Irving Knapp, as mentioned above, a large 

 mass of rock with northerly dip forms conspicuous ledges in the 

 east fork of the mountain roads. It resembles both the quartzite and 

 the gneiss and probably represents a transition from one to the 

 other. The quartzite outcrops along the road east of Knapp's, in one 

 or two places, but is mostly concealed by drift west of the west road 

 from the Hook into the mountains. It was found in the bed of the 

 brook just west of John Ireland's house and about 300 yards south 

 of the Thomas Carey farm on the roadside just above the brook. 

 Some conglomerate occurs at this point. Eastward from the Carey 

 farm, on the farms of Garrett Smith and Ward Ladue, it forms 

 large conspicuous ledges and extends to a point one-fourth of a 

 mile south of Garrett Smith's and terminates with an abrupt talus 

 slope in the woods. The unconformity between the quartzite and 

 gneiss is plainly shown just south of Alonzo Smith's (see plate 4). 

 East of the east road into the mountains, the quartzite extends a 

 little farther south before the gneisses are reached. The southern 

 boundary swings round northwest of the McCarthy place and then 

 east through the woods across the Hook spur to the fault on the 

 east of this. At this point the quartzite was dropped by a fault and 

 is now concealed by surface deposits nearly to the quadrangle 

 boundary. Just north of the road on the west side of the brook 

 it appears in large ledges. Low ledges of limestone outcrop in the 

 meadow just east of the brook. 



Near the quadrangle boundary a small brook, which comes down 

 from Shenandoah mountain, has cut through the surface deposits. 



