30 TT. B. Dwight — Recent Explorations in the 



and which neither of us had ever seen. In the brief time at 

 our disposal, and under the depression of one of the hottest 

 days of the season, we accomplished scarcely anything more 

 than to lay the foundations for future explorations, by getting 

 some, personal knowledge of the topography, and the most ac- 

 cessible points along the rugged sides of this mountain. The 

 quartzyte which we had made our only objective point, we saw 

 only where it was in very compact, homogeneous white masses, 

 and in this, no fossils were found. 



During the last week of October and the first week of No- 

 vember, 1886, Mr. C. D. Walcott and the writer made several 

 joint trips of observation through some of the more interesting 

 portions of the complicated stratigraphy of this eastern border 

 of Dutchess County. We spent the first two days of Novem- 

 ber in paleontological and stratigraphic examination of the 

 strata overlying the gneiss at the southern end of Stissing 

 Mountain. The course which we took after arriving at the 

 Stissingville railroad station, was to follow the valley road run- 

 ning north for a short distance then taking a farm road which, 

 leading westerly, passes along the slopes of the southern ex- 

 tremity of the mountain. We thus traversed the following 

 strata : leaving Hudson River shales at the railway station, we 

 passed over a breadth of limestone, then of bright purple red 

 shales, then, as we ascended the mountain flanks, another 

 breadth of compact bluish limestone, then, at a higher level, 

 quartzose rock, varying between very compact sandstone and 

 quartzyte, and lastly the gneiss composing the bulk of the 

 mountain. 



The compact white quartzyte in the more prominent ledges, 

 as before, proved unfossiliferous ; but as we struck away from 

 the farm-road into the woods to the north, Mr. Walcott soon 

 found loose fragments of less compact, ferruginous, decompos- 

 ing, quartzose rock, completely filled with organic remains ; 

 among these could be detected glabellas and spines of Olenellus 

 with a species of brachiopod and other fossils. In a few min- 

 utes we succeeded in finding this fossiliferous rock in place, 

 showing its fossils, which had mostly been injured by the oxyda- 

 tion of iron, in great abundance. Mr. Walcott soon returned 

 to the ledges of the limestone which overlies the quartzyte, 

 where it was exposed in the road, and by discovering there oper- 

 cula of Hyolithellus micans, thus proved that it also belongs 

 to the same horizon as the quartzose strata. 



Thus the question of the geological age of the quartzyte of 

 Stissing Mountain, as also that at the base of Fishkill Mountain 

 (which we visited together immediately after leaving Stissing), 

 after many years of uncertain speculation, has been solved ; 

 and its solution covers also the knowledge of the age of the 



