THE MESOZOIC AGES. 199 



I have given this preliminary sketch of the whole 

 Mesozoic time, because we cannot here, as in the 

 Palaeozoic, take up each age separately ; and now we 

 must try to picture to ourselves the''life and action of 

 these ages. In doing so we may look at, first, the 

 plant life of this period; second, animal life on the 

 land ; and third, animal life in the waters and in the 

 ocean depths. 



The Mesozoic shores were clothed with an abund- 

 ant flora, which changed considerably in its form 

 during the lapse of this long time; but yet it has a 

 character of its own distinct from that of the previous 

 Palaeozoic and the succeeding Tertiary. Perhaps no 

 feature of this period is more characteristic than the 

 great abundance of those singular plants, the cycads, 

 which in the modern flora are placed near to the 

 pines, but in their appearance and habit more 

 resemble palms, and which in the modern world are 

 chiefly found in the tropical and warm temperate 

 zones of Asia and America. No plants certainly of 

 this order occur in the Carboniferous, where their 

 nearest allies are perhaps some of the Sigillariae; and 

 in the modern time the cycads are not so abundant, 

 nor do they occur at all in climates where their 

 predecessors appear to have abounded. In the quar- 

 ries of the island of Portland, we have a remarkable 

 evidence of this in beds with numerous stems of 

 cycads stUl in situ in the soil in which they grew, 

 and associated with stumps of pines which seem to 

 have flourished along with them. In further illustra- 



