450 FEATHERED ARCH^OPTEEYX OF THE OOLITE. CHAP. xxir. 



Triassic date had consisted almost entirely of fresh or 

 brackish-water beds, in which the bones of terrestrial and 

 amphibious reptiles were the most characteristic fossils. 

 The new fauna was, as might have been expected, in part 

 peculiar, not a few of the species of mollusca being referable 

 to new genera ; while some species were common to the 

 older, and some to the newer rocks. On the whole, the new 

 forms have helped greatly to lessen the discordance, not only 

 between the lias and trias, but also generally between paleo 

 zoic and neozoic formations. Thus the genus Orthoceras has 

 been for the first time recognised in a neozoic deposit, and 

 with it we find associated, for the first time, large ammonites 

 with foliated lobes, a form never seen before below the lias ; 

 also the Ceratite, a family of cephalopods never before met 

 with above the muschelkalk or middle trias, and never before 

 in the same stratum with such lobed ammonites. 



We can now no longer doubt, that should we hereafter have 

 an opportunity of studying an equally rich marine fauna of 

 the age of the lower trias (or bunter sandstein), the marked 

 hiatus which still separates the Triassic and Permian eras 

 would almost disappear. , * 



Archceopteryx macrurus, Owen. I could readily add a 

 copious list of minor deposits, belonging to the primary, 

 secondary, and tertiary series, which we have been called 

 upon in like manner to intercalate in the course of the 

 last quarter of a century into the chronological series pre 

 viously known ; but it would lead me into too long a digres 

 sion. I shall therefore content myself with pointing out 

 that it is not simply new formations which are brought 

 to light from year to year, reminding us of the elementary 

 state of our knowledge of paleontology, but new types also 

 of structure are discovered in rocks, the fossil contents of 

 which were supposed to be peculiarly well known. 



