A YORKSHIRE NATURALIST 37 



shire coast consist of three very distinct super- 

 imposed layers, I became convinced that the fossils 

 characteristic of that stratum were not distributed 

 indiscriminately throughout its entire thickness. 

 I found that, though each of these three layers was 

 well distinguished by its lithological structure, the 

 distinction became much more marked when we 

 examined the fossils which each of them contained. 

 Thus the fossil wood known as Whitby jet, with 

 which even the Romans were familiar, is obtained 

 almost wholly from the middlemost of these three 

 layers, and I observed that many other of the Lias 

 fossils had their respective zones, in which alone 

 they were to be found. 



Struck with these facts, I proceeded to investi- 

 gate the coast strata between the Lias and the 

 Cornbrash, and I found here similar conditions. 

 I embodied these observations in two papers, which 

 were read before the Geological Society of London, 

 one on the Liassic Strata on May Qth, 1834, and 

 the other on the Oolitic Rocks, November 2nd, 

 1836. These two memoirs were ultimately united 

 by the Society, and published in a single memoir in 

 their " Transactions." We shall, I think, shortly see 

 why this was done. 



Towards the end of 1836, and almost simul- 

 taneously with the receipt of my second memoir, a 

 short but carefully prepared paper by Mr. Louis 

 Hunton, a hitherto unknown author, was forwarded 

 to the Society and shortly afterwards read. This 



