part 4] JUEASSIC CHEO^'OLOGY : LIAS. 267 



very rapidh^ to tlie detailed sequence now asked for ; but the 

 deposits are very fossiliferous and especially ammonitiferous. 



This is the age when the Polymorphida? held chief position, 

 while the Liparoceratidie were inferior in importance. 



Table lY (p. 266) gives the evidence in various areas. A pre- 

 sumed faunal repetition of JJptonia {jamesoni and hronni) seems 

 to be the only method of reconciling this evidence. Such faunal 

 repetition is, however, so much in accord with what Kaasay shows 

 in lower beds (see Table V) that the solution seems quite possible. 

 Mr. Lang has also recorded faunal repetition in the case of series 

 of Acanfliopleiiroceras in the Hwiecian and Wessexian of the 

 Dorset Coast, as this and the preceding table show. 



(3) Raasayan. 



The Scottish evidence in this case is excellent and most im- 

 jDortant. The result is to show that in the strata hitherto assigned 

 to the a r ,natum-raricostatum zones the sequence is much more 

 complicated. There are : — 



7. Upper Deroceras horizon. 



6. 



5. y Upper Echioceras horizons — three stag( 



3. Lower Deroceras horizon. 

 1, 2. Suhplanicosta and Lower Echioceras horizon — possibly two stages,, 

 possibly more, see p. 268. 



The Scottish deposits show faunal repetition and faunal alterna- 

 tion of Echioceras and Deroceras, thus giving the clue to the 

 correlation of the strata in other areas. The available evidence is 

 brought together in the accompanying Table Y ; more precise 

 details about the lower horizons would be desirable, and further 

 investigation in Raasaj^ may be expected to furnish them. 



The great thickness of the Scottish strata — five, ten, and eighty 

 times as thick as the English deposits — is the chief factor in dis- 

 playing the sequence. Thus it will be seen that, between the 

 ar matte m zone of the Midlands and that of Radstock, hitherto 

 thought to be isochronous, the Scottish deposits exhibit a thickness 

 of some 800 feet of strata. 



When the English strata are compared with the Scottish, it will 

 be noted that, although no one locality shows the full sequence, yet 

 all put together prove the Scottish sequence. It is evidently the 

 same on the Continent — the Rhone Basin, Freiburg Alps, Bavaria, 

 Wiirtemberg, Hierlatz, contain to some extent heterochronous 

 deposits with dissimilar faunas. Each area lacks something ; but, 

 when all are placed together, they are seen to supply one another's 

 deficiencies, and to make up the sequence of Table Y. Bavaria 

 lacks what Wiirtemberg has, and supplies in part Avhat Wiirtem- 

 berg lacks ; and so with the other Continental areas. 



There is reason to suppose that at the beginning of the Raasayan 

 considerable earth-movement took place producing various local 

 non-sequences — a legacy from Deiran times (see p. 273 and 



