26 NEW YORK STATE MUSEUM 



According to the work of Gushing and Ulrich farther northward, 

 there is an unconformity separating the two formations, the 

 time gap being represented by the upper portion of the Chazy 

 of the Champlain valley. In the Port Leyden district, the change 

 from the conglomeratic bluish dove limestones to the more im- 

 pure whitish, sandy beds seems significant and may be due to 

 an unconformity at this horizon. Certainly, however, the writer 

 has found no evidence of any well defined or large unconformity 

 between the Lowville and Pamelia. 



In the Roaring brook section as measured by Gushing the 

 Lowville is made up as follows : 



Feet Inches 

 6-foot layer of Black River limestone ; upper 3 feet full of 



chert 



Mostly thin bedded blue dove limestone in 6-inch to i-foot 

 layers, full of Tetradium and other fossils, to base of Black 



River "7 8 



Massive beds of blue dove limestone in iS-inch to 2-foot 

 layers ; only sparingly fossiliferous, but more or less Tetra- 

 dium everywhere ". . . 17 4 



Shaly, blue dove limestone i 8 



Blue, granular limestone full of fossils and much crystallized 



calcite i 2 



Ordinary blue dove limestone; lower portion full of gastro- 

 pods ; upper portion a limestone conglomerate with bunchy 

 surface and Stromatocerium look; filling in above are 2-10 



inches of shaly limestone 2 10 



Thin bedded blue dove limestone i i 



Massive blue dove limestone; few fossils and little calcite.... 2 



Blue black dove limestone; full of fossils and crystallized cal- 

 cite ; thin bedded ; shaly above i 5 



Gray, oolitic beds 2 2 



Shaly, impure limestone beds blue dove color i 4 



Gray blue, subgranular limestone; calcite specks and spots.. i 4 



Massive, blue dove limestone ; very fossiliferous ; Tetradium 



abundant 2 10 



Thin bedded to shaly blue dove limestone; mud cracked; 



many fossil fragments 3 6 



Two massive blue dove beds with shale parting; conglomer- 

 atic ; many fossils and calcite spots ; not sure about Tetra- 

 dium 2 8 



Blue black dove limestone, notably conglomeratic; lots of fos- 

 sil fragments and many calcite spots; irregular surface 9 



Thin bedded, mud cracked, dove limestone i 4 



Blue dove limestone spotted with calcite ; conglomeratic ; many 

 fossils ; no Tetradium seen ; abundant quartz sand grains 

 on lower surface ; probable base of Lowville , 3 6 



Total 54 7 



