44 NEW YORK STATE MUSEUM 



zone, on the supposition that the thinness of the bedding is only 

 apparent, and due to splitting on weathering, instead of being 

 original. If this be correct, then bed no. i of this section corre- 

 sponds to the upper part, of no. 2 of the previous section. In an 

 effort to demonstrate the equivalence, these lower beds were traced 

 southwest for 4 miles along the river and railroad, but a drift- 

 covered belt a mile or more in width intervenes between the two 

 sets of exposures. The heavy blue beds of the base of the section 

 are, however, shown to have a thickness of from 6 to 8 feet and to 

 be full of fossils, chiefly Maclureas, and to be underlaid by thin, 

 flinty gray beds, which seem to be the same as those in the quarry 

 section given on page 40, though the full thickness is not shown. 

 Also the Maclurea zone above seems to correspond with the very 

 fossiliferous beds above the thin beds of that section, yet it is the 

 summit of this Maclurea zone that forms the basal layer (no. i) 

 of this Pythian Home section. Our opinion therefore is that the 

 one section is entirely below the other, and that the base of the 

 Pythian Home section is some 40 feet above the base of the 

 formation. 



In the quarries to the east of the Pythian Home, and on the 

 west edge of Ogdensburg, yet" higher beds appear, and the following 

 section was measured: 



Thin-bedded, finely crystalline, sandy-looking dolo- 



r. , ^„ mite, of light color slightly tinged with pink; small 



drusy cavities with tiny quartz crystals ; summit beds of 



the southerly quarry, and above anything in the other. 



Thin-bedded, blue, granular dolomite; summit bed of 

 the northerly and largest quarry. 



Thin-bedded, finely crystalline, gray dolomite with 

 j^ ^, calcareous cement of the sand crystal type; many of the 



beds contain nodules of varying size of white, coarsely 

 crystalline calcite. 



15- I 9' 



Massive layer of dark-blue, granular dolomite, cal- 

 careous cement of sand crystal type and dark colored. 



