422 



Report of the State Geologist. 



The limestone, slate and quartzite continue northeastward in the valley 

 east of Woodcock hill, with somewhat the same relations. 



An examination of the distribution of the limestone, shale and quartzite 

 east and southeast of Woodcock hill, shows the presence of an overthrust, 

 which increases to the south, the quartzite covering the limestone. These 

 relations have been previously determined by Darton, and as the writer 

 came to the same conclusions, the sectional drawing from Darton's paper is 

 reproduced here (Fig. 7). East of the north end of Woodcock hill, a spur 

 of the gneiss, together with the limestone and shale, appears east of the road 

 in Baggs clove. The gneiss is seen just east of the road (340), and the 

 limestone and slate in the woods (341 and 342). The Monroe shales appear 

 at the base of Skunnemunk mountain to the east. The Oriskany quartzite 

 was not seen east of the road at this point, but is exposed in the fields a 

 short distance south. The gneiss, limestone and quartzite disappear to the 

 north, either by thinning out or faulting under the Hudson river shales. 

 The thin strip of Hudson river shale, between the gneiss and limestone east 

 of Woodcock hill is pinched out of place. There is apparently a fault line 

 between the limestone and the gneiss. 



There is a row of gneissoid hills or knobs northwest of the Skunnemunk 

 ridge, which extends from Oxford in a northeast direction, parallel to Skunne- 

 munk mountain, and as far as Cornwall. The relations of these to the rocks 

 southeast and east of them have been already mentioned. 



To the west and northwest they are surrounded by Hudson river slates, 

 which rest unconformably on their slopes. The names of these gneissic 

 hills are Bull hill, Ranier hill, Round hill and Woodcock hill. There is an 

 additional small area near Washingtonville. These hills were no doubt 

 islands in the seas of Hudson river time. 



There is a great similarity in the gneiss forming these knobs, the normal 

 facies being a granular mixture of quartz and feldspar, with little or no mica, 

 Nearly all of the outcrops show evidence of dynamic action in the invariable 

 presence of sheared surfaces. The sections often bear additional evidence 

 of this fact. 



The gneiss of Hull hill is in two areas, a northern, and a southern one 

 which extends just across the Erie railroad track. The northern area jn-esents 

 a very steep northwest face. On the summit near the north end, a large 

 opening has been made for iron-ore. The strike of the gneiss is N. 30° E. 

 and the <lip 4<> L ' S. E. The magnetite follows the dip, and, according to 

 the old inhabitants of that vicinity, has been worked to a depth of 150 feet. 



