300 GENERAL OBSERVATIONS. 



the fragments promiscuously dispersed in the beds ; and in some 

 parts of the oolite, near the surface, we find neither shells nor frag- 

 ments. — In short, the idea that the animals have lived and died on 

 the spot, cannot be reconciled with the phenomena presented ; which 

 rather indicate, that the shells have by some means been entangled in, 

 and mixed with, the clay, the marl, or whatever other substance has 

 formed their matrix, and floating along with it, while it was carried in 

 a semidiluted state, have thus been deposited where we now find them. 

 17. 'I'hough some organized bodies are found only, or chiefly, in 

 certain beds, yet, on the whole, the organic remains ai-e so much dis- 

 persed and intermixed, that the attempt to identify the several strata 

 by their respective fossils, must be confined within narrow limits. — As 

 attempts have been made to arrange all the strata into a regular series, 

 so it has also been attempted, to assign to each member its proper 

 fossils, on the supposition that we may distinguish each stratum by its 

 organic remains. The latter idea, like the former, may be admitted to 

 a certain extent, but the arrangement is far from possessing that univer- 

 sality and certainty which some suppose. We find some organized 

 fossils in the lowest shale only, some in the compact shale only, some 

 in the main alum shale only, some in the oolite only, and so of the 

 rest of our strata containing such fossils; and it is well known, that 

 several corresponding fossils have been found in strata analogous to 

 ours in other parts of England. Where there is a correspondence 

 between the strata, it is natural to expect some agreement between 

 the fossils imbedded in them; and this idea may assist us in tracing 

 their correspondence. Yet the assistance thus furnished must be 

 very limited; for if some fossils appear peculiar to certain beds, there 

 are others very extensively diffused ; and how can we be sure, that 

 such as we deem peculiar to the beds which they occupy, may not 

 be discovered, like their companions, in other beds of a very different 

 description? Most of the shells in the dogger correspond exactly 



