No. 475] 



REVISION OF COMPTONIA 



509 



It is difficult to understand upon what ground Heer founds his 

 two species parvula and porvifolia unless it is because they are 

 from different horizons. He compares both to the European 

 Mijn'ca wningrnsis (Braun) ITeer, although their resemblance to 

 that species, as a matter of fact, is not very close. 



The two are exactly similar excc])t that the form parrifolia is 

 somewhat the larger. The Raritan leaf which Xewl)erry refers 

 to parvula is more like parrifolia, which fact is noted by the latter 

 author, who, I sn])])()s(\ hesitated al)()ut referring a Cretaceous leaf 

 to a species of the hue Miocene as these Arctic deposits were 

 thought to be at that time. 



1 can see no reason for maintaining them as separate species, 

 even though one is Oetaceous and the other Tertiary, a statement 

 not altogether beyond question in view of the fact that labels are 

 sometimes misplaced, and in the case of parvi folia the name was 

 based upon a single imperfect specimen- which might readily enough 

 become included with otlier collections from earlier strata, both 

 having been collected l)y I'rofcssor S(eenstruj)'s ex|H'(Hti()n. In 

 addition to the above, it may 1k> irmarkc.l thai tli(> rxact age of 

 the Greenland Tertiarv drpo^iis ha> nrvcf hfcn (h'tiiiitcly and 

 satisfactorily settled, ami in all j)n)l)ahilily tlic Atanckcnlhik 



Thl-^iiM {\\v or .ix leave, on young plants of the oxl.nu^^ Com p- 

 ionia prnyrina i Linn.' ( oultcr'u.ually (-loscly resemble thi. f.,..il 



parison of the figures whicli I have rcpnMliiccd ; in fact tIu^ cxisrinu- 

 leaves were they to occur as t'os.ils would nnhcsiiarinLdy be referred 



