62 



Carpenter-ant Camponotus herculeanus penn- 



sytvanicus 84, 85 



Rusty Carpenter-ant Camponotus herculeanus penn- 



sylvanicus ferrugineus 90 



Short Caterpillar-wasp Ammophila abbreviata 124 



4. Lowland or "Second Bottom," Red Oak-Blm-Sugar Maple Wood- 

 land Association, Station IV, c 



This station includes the part of the forest located upon the upper 

 or higher part of the river bottom. This area is sometimes called the 

 "second bottom" because it is above the present flood-plain. The gen- 

 eral position of the forest is shown in Figure i, Plate X. The fringe 

 of willows along the river bank is shown at a; the flood-plain area is 

 cleared at b'; the substation forest is at c; and part of the forest of the 

 valley slope is seen at d. Other views of this station are shown in 

 plates XIV, XV, and XVI (figures i and 2). The general slope is 

 toward the river ; minor inequalities are due to the action of the tem- 

 porary streams which are etching into the uplands and depositing their 

 burdens of debris at the mouths of the ravines. Soil, leaves, and other 

 organic debris are washed from the upland, the ravines, and the val- 

 ley slopes, and are deposited upon the bottoms, forming low alluvial 

 fans, which have been built up in successive layers or sorted again and 

 again as the temporary streams have wandered over the surface of 

 the fan on account of the overloading and deposition which filled up 

 their channels. In this manner the soil in general is not only supplied 

 with moisture, drained from the upland, but the various soils are both 

 mixed as successive layers of organic debris are buried by storms and 

 also mulched by the large amount of this debris which is washed and 

 blown to the lowland. No springs were found upon the southeast 

 valley slope, but in the south ravine pools of water were present dur- 

 ing August, 1910, when my observations were made. 



The forest, characterized by hard maple (Acer saccharum), red 

 oak (Quercus rubra), and elm (Ulmus americana), forms a dense 

 canopy which shuts out the light and winds, thus conserving the mois- 

 ture which falls and drains into it, and making conditions very favor- 

 able to a rich mesophytic hardwood forest. That the relative humid- 

 ity is high is shown by the moisture found in the humus of the forest 

 floor, and, further, not only by the presence of clearweed (Pilea pti- 

 mila) and the nettle Laportea canadensis, which characterize such 

 moist shady woods, but also by the presence of the scorpion-flies (Bit- 

 tacus). These organisms are permanent residents where such condi- 



