14 



THE UPPER PORTION OF DUNDRY HILL. [NOV. 1 896, 



XI. The Map of Dundry Hill. 



With this communication we present a geological map of the 

 different deposits and their superficial extent as found by us to 

 obtain at Dundry Hill. As the map of the Geological Survey shows 

 round so very much of the hill the Marlstone of the Middle Lias, 

 and even beds below that, coloured as if they were Inferior Oolite, 

 our map is, we consider, of value in that it amends the official 

 document. But we claim that it is of importance in another respect. 

 That different lithological conditions prevailed at the same time in 

 closely contiguous areas is an accepted fact ; and as a consequence, 

 paheontological divisions do not coincide with divisions founded on 

 lithological characters, as one of us (S. S. Buckman) has repeatedly 

 urged in a series of papers on the Jurassic rocks. "We show in the 

 present paper that this non-agreement between the palseontological 

 and the stratigraphical methods obtains at Dundry compared with 

 surrounding areas ; and therefore the divisions accepted by us in 

 our mapping are based upon purely palaeontological lines. We 

 present therefore what is really the first Jurassic map of any area 

 in which such divisions have been represented. The divisions which 

 we have adopted are as follows ; and in order that they may be 

 compared with the divisions adopted in their maps by the officers 

 of the Geological Survey, we place the two side by side : — 



Quenstedt's Divisions 



in Germany 



(stratigraphical and 



palaeontological). 



The present Divisions 

 (chronological, based 

 solely on palaeonto- 

 logical evidence) 



The Geological Survey Divi- 

 sions (stratigraphical). 



Brauner Jura Z, 



Brauner Jura e 



Brauner Jura d (pars) 



Brauner Jura d (pars). 

 Brauner Jura y 



Brauner Jura (3 



Brauner Jura a 



Schwarzer Jura Z, 



Schwarzer Jura e 



Schwarzer Jura d, etc. 



fBathonian ... 



Bajocian 



!• Aalenian 



1-Toarcian 



Charmonthian 



From the upper portion 

 of the Interior Oolite 

 up to the Kellaways 

 Rock inclusive. 



Inferior Oolite (pars). 



c Inferior Oolite (pars). 

 I Midford Sands (pars). 



c Midford Sands (pars). 

 I Upper Lias. 



r Middle Lias. 



I Upper part of L^wer Lias. 



