GEOLOGICAL POSITION AND GEOGRAPHICAL DISTRIBUTION 2 I I 



of the Trenton limestone formation proper, is thin-bedded 

 and shaly and unfit for building stone. In the Birdseye 

 also the stone of many localities is disfigured on weather- 

 ing, by its peculiar fossils. Generally the stone is sub-crys- 

 talline, hard and compact and of a high specific gravity and 

 dark-blue to gray in color. But the variation is wide, as for 

 example, between the black marble of Glens Falls and the 

 gray, crystalline rock of the Prospect quarries near Trenton 

 Falls. The variation is often great within the range of 

 a comparatively few feet vertically ; and the same quarry 

 may yield two or more varieties of building stone. In sev- 

 eral quarries the Birdseye and Trenton are both represented. 

 Many quarries have been opened in the formation and there 

 are many more localities where stone has been taken from 

 outcropping ledges, which are not developed into quarries 

 proper. The more important localities which are worked 

 steadily are : Glens Falls, Amsterdam, Tribes Hill, Cana- 

 joharie, Palatine Bridge and Prospect In the valley of the 

 Mohawk ; and Lowville, Watertown, Three Mile Bay, 

 Chaumont and Ogdensburgh in the Black river and St. 

 Lawrence valleys. The railroad and canal lines, which trav- 

 erse the territory occupied by these formations, afford trans- 

 portation facilities and offer inducements to those who are 

 seeking new quarry sites where these limestones may be 

 found in workable extent. 



Niagara Limestone 



The Niagara limestone formation Is well developed west 

 from Rochester to the Niagara river ; and there are large 

 quarries in it at Rochester, at Lockport and at Niagara 

 Falls. The gray, sub-crystalline stone in thick beds is 

 quarried for building purposes. It is filled with encrinital 

 and coralline fossils and the unequal weathering of the 

 matrix and the fossiliferous portions are sometimes such as 

 to give the dressed surface a pitted appearance and with 

 cavities which roughen and disfigure it. For foundations 



