WATER SOILS. 383 



The formation of these mounds is ascribed not to the activity of ants 

 but to the escape of gna throuiih fractures produced by earthciuake 

 shocks in tlie strata, the gases, in their passage tlirougli the water, car- 

 rying up from below the sand which is the peculiar constituent of these 

 mounds. 



As regards the geological history of the region, it is stated that — 



''The Florida parishes are a part of the coastal i)lain that borders the Atlautic 

 Ocean and Gulf of Mexico from New England to and bej'ond the Rio Grande. The 

 coastal lowland, averaging about 150 miles in width, maj- everywhere be divided 

 into 2 and often 3 distinct types of topography. 



''The 'low grounds' of the Caroliuas and the ' pme meadows" and 'pine llats' of 

 Alabama, Mississippi, and Louisiana, constituting the seaward division of the coastal 

 plain, are, as has been described, topographically young. Their illy drained areas 

 extend up all the transecting primary streams and many of the secondary. 



''The landward division of the coastal plain is topographically mature. Its per- 

 fectly drained surface is made up of a succession of hills and ridges whose even 

 crests show them to be the tattered remnants of a former peneplain. 



" The third type of toi)ography is found as bordering zones along the great streams 

 whose tributary' sources were in the regions of the northern continental ice sheet. 

 While the sediments constituting the strata of this type were deposited quite as late 

 as those of the pine Hats, yet the attitiule of the laud is such that topographic forms 

 have been of rapid development, and the topography of these areas is not inaptly 

 styled adolescent. 



"This coastal lowland, constituting the most recent important addition to our 

 continent, belongs to the Lafayette and Columbia formations. These fornuxtious, 

 recent subdivisions of the Orange Sand of llilgard and other geologists who studied 

 this region, while not fully determined as to exact geological position, are probably 

 late Tertiary and Quaternary. Being almost destitute of fossils, biologic criteria 

 can not be used in fixing them in the geologic section, and resort must be had to 

 the ])rinciple that ' geologic history may be read from the configuration of the land 

 as readily as from the contemporaneous rocks and fossils.' This being the case, a 

 geologic province should include alike the areas of degradation and concurrent 

 dei)osition." 



Applying this method, a brief history of the Lafayette and Columbia 

 formations is worked out. 



In the Florida parishes sandy, clay, and humus soils are distributed 

 over large areas. 



"From the nature of the deposit the greatest amount of humus is found in the 

 soils of the river bottoms, especially the tirst bottoms, that are subjei-t to overtlow. 



"The 'second bottoms' and 'pine flats' while containing considerable amounts of 

 humus are more especially characterized by the development of that ilistiuctly 

 clayey group of strata, the Port Hudson, which produces a heavy soil. 



"Moreover, much of the soluble plant food from the liill soils has been deposited 

 there. 



"These all combine to make these soils inherently fertile or strong. This has long 

 been rec(jgni/,ed in the modern alluvial deposits over the Hood plains of streams, hut 

 as yet unappreciated in the 'flats' and 'second bottoms' that constitute nearly one- 

 half of those* parishes east of the Amite. 



"In their present nndrained condition these soils are soni- and unproductive. 

 This can be completely corrected by tliorougli drainage and some addition of lime 

 to assist in clianging the brown, solnble humus into thc^ true black humus desired. 



"When tliis is done these lands will become among the most valuable in the State. 



'•Over the hills of these parishes, east of the zone of 'bluff' bordering the 



