NIAGARA FALLS AND VICINITY 67 



Within the old channel thus outlined, which was much broader 

 than the modern channel below the falls, accumulations of stratified 

 sands and gravels were formed in the more protected places, much 

 as such deposits are formed in streams today, where sands are swept 

 into protected areas. With these sands and gravels were swept to- 

 gether the shells of those mollusks which lived in the river water, 

 and many of which were of the species now found living in the 

 upper Xiagara. 1 Most of the shells thus swept together were prob- 

 ably of dead individuals, though living ones may also have been 

 carried into these growing deposits. Many excavations have been 

 made in these ancient deposits, fragments of which are preserved in 

 various places between the former and present banks of the river. 

 The most notable of these and the one longest known is on Goat 

 island, perhaps a quarter of a mile inland from the edge of the cliff, 

 at the Biddle stairway. In the section opened here, most of the 

 material is seen to be coarse and rudely stratified. The pebbles 

 are subangular, often quite angular, while some appear to be scarcely 

 worn at all. Blocks a foot or more in diameter are not infrequent, 

 the material being generally limestone from adjoining ledges, 

 though fragments of sandstone and of crystalline rocks are not un- 

 common. Occasionally a lens of fine sand occurs which shows 

 cross-bedding structure, the laminae pointing in a northwesterly di- 

 rection. The shells are found on the cross-bedding planes, con- 

 forming with them, and indicating that they were spread there by 

 the current which moved the sand grains. Among the coarse ma- 

 terial the shells are mixed indiscriminately. In many cases the 

 gravels are of the loose type, with scarcely any sand between them, 

 indicating deposition by a powerful current. Along these zones air 

 and water have most readily penetrated, and a deposition of iron 

 oxid has been formed which stains both pebbles and shells. The 

 shells are generally very fragile, and commonly show signs of wear. 

 Gastropods are most abundant in the Goat island gravels. 



In Prospect park several excavations formerly exposed these 

 gravels. The deposit here consists of sand and gravel with the 

 pebbles moderately rounded, though occasionally subangular, and 



a For descriptions and illustrations of these shells, see chapter 5. 



