S. 8. Buckman — The Term ' Hemera.' 55T 



Now we cannot separate the stratigraphical from the palaeontological 

 phenomena; the two go together. Zones are not bands of rock 

 merely, for the strata of a zone may be heterogeneous vertically 

 or horizontally. The zones are really so many entombments of 

 organisms, which entombments are shown to be successive by 

 the way in which they occur in the strata. For these successive 

 entombments as they are exhibited in the strata, why should we not 

 use a term faunizone ? With distinct terms for the different meanings 

 we shall express ourselves much more clearly. 



To return to hemera, I have been asked if it is advisable when 

 faunas differ, and when the index species is absent, to use different 

 names as hemeral designator's. I say that it is not advisable. 

 Temp. Edward VII may date an event in Australia as well as in 

 England, even though Edward VII never visits Australia. So 

 hemera Murchisonce will date a deposit in a locality where Murchisonm 

 never resided. 



Certainly in historical records each nation bas dated its events 

 by the reigns of its own monarchs. Yet it would, in the interests 

 of a universal system, be quite correct, from a chronological point 

 of view, to say that certain events happened in Spain temp. Queen 

 Elizabeth (of England). It is the aim of science to be universal 

 and independent of nationalities. It is the aim of geology to have 

 a universal chronological system, not to apply different and therefore 

 confusing names to contemporaneous periods of time merely because 

 of local faunal differences. And when, as in the Jurassic rocks, the 

 sequence of faunal phenomena from Wiirtemberg to England can 

 be accurately described by one set of hemeral terms, we may 

 reasonably hope that, as our knowledge increases, if we take the 

 necessary trouble, a universal chronology may be possible. And 

 if that can be done in the Mesozoic rocks how much more may 

 we not expect it in the Palgeozoic, seeing that, as Dr. H. Woodward 

 tells us, " the ancient faunas of the earth were far more widespread, 

 more simple, and more uniform than are our recent faunas." ^ 



To sum up, a zone indicates the horizontal extension of species, 

 and so is a geographical term ; a biozone is the range of any organism 

 or group of organisms in geological deposits, so it may be said to 

 indicate vertical extension ; faunizones are, to paraphrase Mr. Marr, 

 " belts of strata, each of which is characterised by an assemblage 

 of organic remains," with this provision, that faunizones are 

 independent of lithic structure — the strata of a faunizone may vary 

 horizontally or vertically, or the strata may not vary and yet may 

 show several successive faunas. So faunizones are the successive 

 faunal facies exhibited in strata. Lastly, hemera is a time term — the 

 subdivision of an ' age ' ; it indicates the period of time from the rise 

 of one dominant species to the rise of the next. It is the time term 

 which corresponds to 'faunizone' as the stratigraphical term, just 

 as ' age ' corresponds to ' stage.' 



1 Anniversary Address of the President to the Geological Society, Q.J.G.S.,. 

 vol. li, p. Ixxxni. 



