34 CONTRIBUTIONS TO THE 



of July, August and September, warm southerly winds and a 

 glowing sun were combining to dissolve, with utmost rapidity, 

 the vast masses of ice which still lingered in the country. The 

 channels were then compelled to carry off not only the annual 

 precipitation, but the stored-up precipitation which had been 

 accumulating as glacial ice for thousands of years." "These 

 floods along the lines of glacial drainage have left their marks, 

 and their direction and extent can be traced almost as readily as 

 in the case of the present streams." 



The careful observer upon our own ground, within thirty min- 

 utes walk of the mayor's ofifice, will find sand and gravel terraces 

 one or two hundred feet above the present flood-plain ; and these 

 terraces approximate if they do not accurately mark the highest 

 stage of the closing floods of the ice-age. 



VEGETABLE SURVIVALS. 



Scattered at not rare intervals throughout this section a few 

 sassafras trees may be found, but they are more frequently met 

 with upon the shore and islands of Massabesic lake. Two spec- 

 imens of the slippery elm are growing in the fine grove known 

 as Arcadia, northwest of Rock Rimmon and upon the east ter- 

 race of the Piscataquog. These are the only specimens of this 

 tree, growing wild, with which we are acquainted in this vicinity. 

 Cedars are not uncommon, and are frequently seen, being more 

 plentiful toward the sea-coast. 



These with other curious survivals of a former tropical climate 

 in this latitude, probably closely following the age of ice, are of 

 great significance, and we offer them in cumulative support of 

 the existence of such a period ; and the recorded and published 

 facts concerning the discovery of the remains of tropical animals 

 and plants as far north as southern Greenland, removes our mod- 

 est assumptions from the charge of improbability. On the oth- 

 er hand we have purposely refrained from giving here a cata- 

 logue of survivals of an arctic flora and fauna, which undoubt- 

 edly accompanied the age of arctic ice-fields. 



