ERIE COUNTY. ; 185 
more or fewer, generally small, bowlders, usually ground and striated, 
derived from the crystalline rocks north of the lakes. In this part of 
the county are also found beds of sand and the lake ridges which rest 
upon the bowlder clay. These latter deposits are evidently the effect 
of shore waves, and are in fact old beaches formed when the Lake stood 
much higher than it now does. A good illustration of the mode of 
deposition of such sand banks and ridges is seen on the lake shore 
between Cedar Point and Huron. Here the mouth of Sandusky Bay 
is partially closed by a ridge thrown up by the waves which will ulti- 
mately dike out the Lake from and reclaim a large area formerly covered 
by navigable water. The lake ridges which are found at different eleva- 
tions, running parallel with the lake shore through many counties of 
northern Ohio, are popularly called “lake ridges,” and no better proof 
of the truth of the theory of their origin implied in this name could be 
asked than the example I have cited. Between the ridges and sand- 
hills which stretch east and west, north of Prout’s Station, is a surface 
level to the eye formed by a fine black soil, which covers the limestone 
here presenting a remarkably level surface, and nowhere deeply buried. 
This district was originally prairie, with islands of timber, and has 
proved the most fertile and productive portion of the county. The ori- 
gin of the peculiarities of this district—its monotony of surface; the 
absence of Drift deposits; its sheet of fine, largely organic soil, and its 
prairie character—though so striking, are, it seems to me, not difficult 
of explanation. We have here a broad surface of limestone planed down 
nearly as level as a house floor. This was doubtless once covered with 
Drift clay, but this has been removed by the waves of the Lake when 
they swept over it. Subsequently, when the water of the Lake had been 
withdrawn, this tract was left in a condition similar to that of the upper 
end of Sandusky Bay, or to that of the space behind the barrier east of 
the city, viz., covered with shallow, quiet water, which was gradually 
replaced by a fine sediment, mixed with the remains of the luxuriant 
vegetation that grew there. The result was a sheet of remarkably fine, 
rich soil, having all the characteristics of the prairie soils of the West, 
and, like them, covered with a growth of grass rather than trees. In 
- future ages, when Lake Erie shall be further drained, what is now San- 
dusky Bay will undoubtedly present nearly the same appearance as the 
district under consideration. As the facts observable in this locality 
have a bearing on the theory of the origin of prairies, they are referred 
to in the notes on this subject, Vol. I., Pt. I., p. 26, of this report. 
Castalia Springs.—The phenomena presented by Castalia Springs have 
excited considerable curiosity and interest, both on the part of residents 
