306 Proceedings Portland Society Natural History 



b. Association-types of depositing areas along the 



coast 367 



Association-types of shingle beaches 367 



Association-types of gravelly and sandy beaches 368 



B. SECONDARY FORMATIONS OF THE XERARCH 



AND MESARCH SERIES 375 



1. Formations Due to Human Activity 375 



a. Association-types due to cultivation 375 

 Association-types of fallow fields 375 

 Association-types of abandoned fields 376 



b. Association-types due to fire 379 

 Association-types where humus is little injured 380 

 Association-types where humus is absolutely de- 

 stroyed 382 



Association-types of blueberry barrens 385 



c. Association-types due to lumbering 386 



C FORMATIONS OF THE HYDRARCH SERIES 390 



1 Formations of Lakes, Ponds, and Swamps Inland 390 



a. Association-types of permanent well-drained 



lakes, ponds and lake-swamps 393 



Association-types of the lake series 393 



Association-types of the swamp series 397 



Association-types of cedar swamps 399 



b. Association-types of periodic lakes and ponds 400 



c. Association-types of permanent undrained lakes, 



ponds and lake-swamps 403 



Association-types of ordinary bogs 403 



Association-types of raised bogs 408 



d. Association -types of spring swamps 411 



e. Association-types of poorly drained swamps 415 



2. Formations of Lakes, Ponds, and Swamps Along 



the Seacoast 419 



a. Association-types of barrier beach ponds 420 



b. Association-types of salt marshes 420 



c. Association-types of brackish marshes 424 



V. Comparisons with Other Regions 428 



VI. Summary 433 



VII. Bibliography 435 



