FiNLAY AND McDowaur.—Preliminary Note on Clifden Beds. — 531* 
there are certain genera, such as Natica, Turritella, Venericardia, Leuco- 
syrinz, Pseudotoma, Divaricella, Crepidula, Calyptraea, and many others, 
which extend in an unbroken evolutionary line of slowly changing species 
(and deceptively) similar. To this also is due the statement repeatedly made 
arshall* that the ылы heaps of any fauna can be found 
in the one preceding it. This is true for such genera as mentioned above, 
but unless it is true for all the po Marshall's argument does not seem 
to be logical. It is only to be expected that the hardy members of o 
original fauna would, under conditions of comparative isolation, punt 
with but little change for a long time; there is no need to insist on 
absolute isolation. Further, this fraction of our various faunas, though 
реса ally often overwhelming, is the least important; what one must 
nsider most is the residue of short-living species and newly appearing 
here seems to be no doubt that the ancestors of many forms 
cannot be traced E earlier horizons, and it is not reasonable to suppose 
that this is always due to imperfect collecting. As our knowledge stands 
at present it is impossible to assume that the Clifden fauna was wholly 
derived from that found in the Waia ы. an greensands at McCullough’s Bridge, 
the Wangaloan, though in each case evolution is no doubt responsible for 
rt i f the 
a certain The real problem to be solved is the origin o 
remainder 
Dr. Marshall has so consistently urged the continual isolation of New 
Zealand, and the evolution of every fauna from its predecessor, that the 
believe that the molluscan evidence is at present e imperfect to allow 
of the postulation of definite land connections. Four gs must » done 
and for a fossiliferous facies of the part of that stage known only as 
“ limestone "; (4) more thorough comparison with Australian and South 
American Санага unas. 
In order that our conclusions as to the age of the Clifden beds may 
more readily followed, we append a brief list of some of the characteristic 
f d 6. Positive identifications are as yet made in only the 
few cases where no doubt can exist: “ cf.” indicates that the iet is маға 
close to the species mentioned, judging from literature, but m 
aff." indicates that the species is certainly new, but has its Push ные 
in the species mentione 
We would also like to mention that wherever comparisons with various 
faunas have been mentioned our conclusions have been drawn from a study 
of actual specimens ; we have at no time relied on lists of fossils from the 
localities concerned. 
for instance, Trans. N.Z Inst., vol. “ына р. cm 77, i vol. 51, p. 44, 1919 ; 
* See, 
vol. 52, р. 126, 1920; and vol. 53, р. 96, 1921. From t the ast ref erence s following 
may be quoted: “We A" e, then, been forced to ie conclusion that from the 
ag Mes and Ham стей were deposited until marine 
present day t 
ca aland have эни а gradual development, without any important 
additions at any гок from other fauna regions.’ dia 
