222 The Founders of Geology LECT. 



like Guettard's, but had a horizontal section, which showed 

 the Jurassic series lying unconformably upon the edges 

 of the Palaeozoic slates, and covered in turn by the Gault 

 and the Chalk. 



While in France it was the prominence and richly 

 fossiliferous character of the Tertiary strata which led to 

 the recognition of the value of fossils in stratigraphy, and 

 to the definite establishment of the principles of strati- 

 graphical geology, in England the same result was reached 

 by a study of the Secondary formations, which are not 

 only more extensively developed there than the younger 

 series, but display more clearly their succession and per- 

 sistence. But in both countries the lithological sequence, 

 being the more obvious, was first established before it was 

 confirmed and extended by a recognition of the value of 

 the evidence of organic remains. 



As far back as the year 1760, in a remarkable and 

 well-known paper on Earthquakes, the Eev. John Michell 

 gave a clear account of the stratified arrangement of the 

 rocks of England, describing their general characters and 

 the persistence of these characters for great distances, and 

 showing that while on the flat ground the strata remain 

 nearly level, they gradually become inclined as they ap- 

 proach the mountains. 1 He pointed out that the same sets 

 of strata, in the same order, are generally met with in cross- 

 ing the country towards the sea, the direction of the ridge 

 being towards the north-north-east and south-south-west. 

 That he was familiar with the broad features of the suc- 

 cession of strata in England from the Coal-measures of 

 Yorkshire up to the Chalk is shown by an interesting 



1 Phil. Trans, vol. li. (1760), part ii. p. 566. 



