214 Observations on the south side of Ontario Valley. 
stream through the great Tonawanta or Oak Orchard 
down the valley of Tonawanta creek. Al 
Grand Island, and the small ones around it, are of this clay 
it may be traced far west on the Chippewa, and over 
on the Grand river. ~ 
The lime stratum of Niagara Falls, with shells, is of very 
great extent, particularly eastward. Over it falls the Oak 
hard creek, Genessee river, Canandaigua outlet, Seneca 
outlet, and the streams from the lakes Owasco, Skaneateles, 
and Otisea, and it may be traced as far east-as the falls of 
Skanado creek in Oneida county. The terminating edge of 
this lime stratum, is generally very straight, and varies but 
little from an east and west course. For the first 20 miles 
east of Niagara river, it ends in a denndated rock, project- 
ing so much, that when tracing the level of the surface of 
lake Erie along the north side of it, in 1810, it was found 
a very convenient shelter from the showers. 
Mr. William Smith and his followers, observe on the 
British strata, that im all the eastern parts of England, they 
“end successively towards the N. W., generally with a fin- 
** gered, or digitated outline, running out into ridges, be- 
** yond the general range of the edge or limit of the stra- 
“tum.” The outline, or terminating edge, of this great 
lime stratum, which is such a distinguishing feature in the 
south side of the great Ontario valley, is towards the north, 
and instead of a fingered form, thus, 
Sidi, may be represented 
= side above the line, the terminating edge or END- 
eae as Mr. Smith would term it. ‘This formation, as has 
mentioned, is more particularly to be observed between 
of svg chasms that run back, south of the general range 
termination, streams run from the level table-land above, 
ae ar every superficial observer, more particularly the one in 
) river, 
which runs the Niagara ri 
