SIXTH REPORT OF THE DIRECTOR ICjOO, IOO. 



Feet 



4 More of the dark gray, evil smelling- dolomite, like that 

 above; all is somewhat porous, the voids between the 

 dolomite rhombs not thoroughly cemented up ; there is 

 always a small percentage of calcite cement n 



3 Concealed 1 1 



2 Gray, finely crystalline dolomite, lighter colored than that 

 above and below, very massive, marked with dark col- 

 ored lines, and containing some chert 15 



1 Dark, blue gray, porous dolomite, at base of section 1 



119 



This section terminates at the north in the angle between two 

 branches of a fault, making it impossible to determine what 

 thickness of similar beds may lie beneath. The light gray, crys~. 

 talline dolomites of the upper portion of the section continue on 

 to the south through Saratoga, with likely some additional beds 

 which do not appear in the section, but the thickness of such 

 can not be great- — probably less than 15 feet. Four miles west 

 of Saratoga a hill composed of these same beds is capped by a 

 dove limestone layer which is a great Cryptozoon reef, and which 

 is likely at a somewhat higher horizon than any bed of the sec- 

 tion; but it lies upon light gray, crystalline dolomites precisely 

 like those which form the upper beds of the Highland Park 

 section and can not be greatly higher than these. 



The best section of the lower beds, Potsdam sandstone and 

 Hoyt limestone, is found along the Adirondack Railroad to the 

 west of Saratoga. It is as follows, the beds being numbered 

 from below upward : 



CONSECUTIVE SERIES OF SECTIONS EXPOSED IN CUTS ALONG THE ADI- 

 RONDACK RAILROAD AND NEARBY QUARRIES BETWEEN GREENFIELD 

 STATION AND SARATOGA 



40 Exposures at Hoyt quarry ; hard, blue to blue black, sub- 

 crystalline to crystalline magnesian limestones, largely 

 of dolomite rhombs with calcareous cement; 1 foot 

 from the top is a Cryptozoon reef, and the base is 

 composed of another, the one shown by the roadside 

 near the farmhouse, from which Hall originally de- 

 scribed Cryptozoon proliferum; the rock is 

 partly thin, and' partly thick bedded; some of the layers 



