No. 104.] 197 



The two formations lie side by side along the Hudson river valley, 

 extending northward through Washington county and into Vermont 

 and Canada. 



To the westward, the Hudson river group extends along the Mohawk 

 valley, and thence in its upper members through Lewis and Oswego 

 counties ; overbearing in its upper part some heavy-bedded gray 

 sandstone which is available for foundations and rough masonry, 

 but I am not aware that it has been much used in the superstructure 

 of buildings. 



3. The Medina sandstone formation, from its eastern extension 

 in Oswego county to the Nigara river, furnishes building stone in 

 some of its beds, which, in some localities, is good and reliable, while 

 in other parts of the same formation it becomes rapidly disintegrated 

 upon exposure to the atmosphere. It is quarried at Fulton and 

 other places in Oswego county, and at a few points in Wayne 

 county. It has been heretofore quarried on the Genesee river below 

 Rochester ; but the more reliable quarries are at Holly, Albion, 

 Medina and Lockport ; and again it crops out in the bank of the 

 Niagara river above Lewiston, where it can be worked with facility. 

 The formation furnishes valuable flagstones in the neighborhood of 

 Lockport. 



4. Sandstones of the Clinton group. The Clinton group is 

 made up of a series of shales, thin beds of limestone, and impure 

 shaly sandstone with more perfect beds of the latter. In Herkimer 

 county, on the south side of the Mohawk river, there are some beds 

 of brown sandstone in this group which are worthy of attention. 

 The material is mainly siliceous and the texture good. So far as 

 known, these beds are limited within the width of the count\\ In 

 the same neighborhood, and lying above the brown beds, there is a 

 considerable thickness of gray siliceous sandstones of the most dur- 

 able character. So far as known, the rock has not been quarried to 

 any considerable extent, and its economic value is, therefore, not 

 fully known. In other parts of the Clinton group, there are thin 

 flaggy beds which are used for rough building or foundation stones. 



5. The Oriskany sandstone, though a good and valuable stone in 

 some of its strata, does not occur in such thick or extensive beds as 

 to render its use very extensive, and, except locally, it is unknown 

 as a building stone. 



6. Freestones or argillaceous sandstone and flagstone of 

 the Portage group and upper part of the Hamilton group. In 

 Eastern New York, the upper part of the Hamilton group and lower 

 part of the Portage group yield an abundance of the tinest flagstone 

 yet known in any part of the country. Some of these beds become 

 thick enough for building purposes; and the fine ^^hlue stme^'' of 

 the iMalden quarries on the Hudson river (now much used), is from 

 the lower part of the Portage group. In Central New York, the 

 upper part of the Portage group yields an abundance of fine-grained 

 argillaceous sandstone, which is not always durable. In the extreme 



