— 180 — 



glow at each successive Period of vital gradation and 

 progress. , 



The so-called "Dawn-of-Life" begins with the 

 Cambrian Era or Period with its obscure zoophytes, 

 trilobites and shells, of which age the trilobites, namely 

 the Paradoxides, were the princes. Some Geologists 

 begin with a lower Bra which they term the Lau- 

 rentian : the Laurentian rocks, in other words the 

 Metamorphic rocks, are met with specially in Scot- 

 land and in Canada. Before going further it would 

 be better to recall that the Geological strata are 

 divided into three principal Series, which are the 

 Palaeozoic or Primary Series — the Mesozoic or Secon- 

 dary, and the Cainozoic or Tertiary Series, each of 

 which Series is subdivided into Groups namely the First 

 (Palseozoic or Primary) into the Laurentian, the 

 Cambrian, the Silurian (lower and upper) the Devo- 

 nian, the Carboniferous and the Permian Groups — 

 the Second Series (the Mesozoic or Secondary) into 

 the Triassic, the Jurassic (subdivided into the Lias, 

 the Lower, Middle and LTpper Oolite, and the 

 Wealden ) and the Cretaceous ( lower and upper ) — 

 the Third Series ( the Cainozoic or Tertiary) sub- 

 divided into the Eocene, the Miocene, the Pliocene 

 and the Pleistocene groups — The First Series, namely 

 the Paloeozoic may be called the Ancient Life Period, 

 but before this, we have the Metamorphic or Lau- 

 rentian Rocks, which constitute the Under Life Period 

 ( Hypozoic ), i.e. the strata lying beneath the 



