260 Mr.Michell’s Geological Opinions, and Observations 
by W.* There are)many more instances of this to be met with 
in the world, if we may judge from circumstances, which make 
it highly probable, that it obtains, in a great number of places, 
and in several they seem to put it almost out of doubt. 
47. The reader is not to suppose, however, that, in any in- 
stances, the highest rise of the ridge, and the inclination of the 
strata from thence to the countries on each side, is perfectly uni- 
form; for they have frequently very considerable inequalities, 
and these inequalities are sometimes so great, that the strata are 
bent for some small distance, even the contrary way from the 
general inclination of them. This often makes it difficult to 
trace the appearance I have been relating, which, without a ge- 
neral knowledge of the fossil badies(7) of a large tract of country, 
it is hardly possible to do. 
48. At considerable distances from large ridges of mountains, 
the strata, for the most part, assume a situation nearly level ; and 
as the mountainous countries are generally formed out of the 
lower strata, so the more level countries are generally formed out 
of the upper strata of the earth. 
49. Hence it comes to pass, that, in countries of this kind, 
the same strata are found to extend themselves a great way, as 
well in breadth as in length: we have an instance of this in the 
chalky and flinty countries of England and France, which (ex- 
cepting the interruption of the Channel, and the clays, sands, &c. 
ot a few counties) compose a tract of about three hundred miles 
each way, 
50. Besides the rising of the strata in a ridge, there is another 
very remarkable appearance in the structure of the earth, though 
a very common one; and this is what is usually called by miners, 
the trapping down of the strata; that is, the whole set of strata 
on one side a cleft are sunk down below the level of the corre- 
others of Plutonic and Geognostic celebrity), but up the vale of the Leith,” 
nearly, completely on their north-western side.—J. F. 
* Of this I could give many undoubted proofs, if it would not too far 
exceed the limits of my present design, and which, for that reason, I am 
obliged to omit. we 
(7) Mr. Smith’s detractors would fain make it out, that Mr. Michell 
here meant organized remains: it this were in the least apparent, I would 
not hesitate an instant, in giving him the praise due to so important a sug- 
gestion: plainly however, Mr. M. intimates, that the requisite knowledge 
of the *¢ fossil bodies,” of whatever kind, was not then possessed by him:— 
my highly-injured Friend Mr. Smith, did possess the useful knowledge, and 
was liberal ix communicating it, of the unorganized and organized bodies. 
“¢ of a large tract of country,” years before Geognosts, or any of their hand- 
specimen mineralogical Theory of the whole Earth, was to be heard or read 
of in this country.—J. F. 
sponding 
