DIVISIONS OF GEOLOGICAL TIME 385 



3. ZONES OF THE UPPER JURASSIC. 



* Quenstedt divided the whole Jurassic System into three the Black Jura, Brown Jura, 

 and White Jura, for which Oppel's equivalent terms were Lias, Dogger, and Malm. Each 

 of these three w,\s divided into six divisions, marked by the Greek letters a, , y, 8, e, and . 

 The whole of the White Jura and most of the Brown Jura come in the Upper Jurassic ; the 

 rest of the Browa and all the Black Jura in the Lower Jurassic. 



