156 H. r. GUSHING PALEOZOIC IN NORTHWESTERN NEW YORK 



bedded weak sandstones -was found — a series which is Hthologically pre- 

 cisely hke beds which, in the region farther east, lie between the Potsdam 

 and Beekmantown formations and have always been regarded as "passage 

 beds" between these two formations. The Avork of the first field season 

 closed before tlie beds next overlying had been seen, but it was confidently 

 expected that they would be of Beekmantown age and character, since all 

 observers who had studied the district had described and mapped this 

 formation as present here. 



Before entering on the work of the next field season, application was 

 made to the state geologist to, if possible, detail a paleontologist to accom- 

 pany me into the field, and Doctor Euedemann was so detailed. He had 

 in a previous season done some sectioning and collecting along the Black 

 river, in the "Watertown region, and had thus acquired an intimate knowl- 

 edge of the Trenton and Black Eiver formations there, as well as of the 

 upper part of the Lowville beneath, though he had published nothing on 

 the work. Because of this we commenced work at Watertowu, studying 

 and mapping such Trenton as occurred within the limits of the Theresa 

 quadrangle, with the underlying Black river and upper Lowville, and 

 then carried our work northward and downward in the section. "We 

 found that the normal fossiliferous limestones of the upper Lowville 

 passed downward into similar limestones with an ostracod fauna, and 

 that iinderneath these was a large thickness of other ostracod limestones, 

 M'ith interbedded light-colored, impure limestones, which as a whole pre- 

 sented a considerable lithologic contrast to the normal Lowville, but 

 which, if not Lowville, we were unable to correlate with either Beelonan- 

 to\\-n or Chazy rocks as known to us on other sides of the Adirondack 

 pre-Cambrian area. We could find no sharp lithologic line between the 

 two limestone groups, except we drew it at the upper limit of the light- 

 colored impure beds, and it appeared to us that if we were in reality 

 dealing -with two separate formations they must of necessity be closely 

 related ones. 



At this stage the work was interrupted, our presence being required on 

 lake Champlain, at the summer meeting of Section E. At this meeting 

 appeared Dr E. 0. Ulrich, of the IT. S. Geological Survey, who had come 

 to ?few York for the purpose of studying the Paleozoic section around 

 the Adirondack region, his extensive knowledge of the rocks of similar 

 age in many other parts of the country rendering it exceedingly desirable 

 tliat lie should have a first hand aec(iiaintance with the New York type 

 section. In this work he was accompanied by Doctor Euedemann ; hence 

 I returned to the field alone at the close of the meeting, after arranging 

 with them that we should meet at Watertown, when thev reached that 



