LOUISIANA. 



way tbrough the bine clay }uto these 

 saiuls or gravels. At high water the 

 veioi.'Uy of this stream is consideraljly 

 aiigineiited aud, therefore, the iucroased 

 erosi\e force of its waters wear away 

 these niulerlyiiij; sands and gravels and 

 leave the suiterimposed clay stratum lui- 

 dermiiied, which, when the flood recedes, 

 unsuijported by the buoyancy of water, 

 yields to the force of gravity aud falls 

 into the river, giving, in many instances, 

 disastrous caves. The gravel of this 

 Jormatiou is found overlying the salt 

 lieds of Avery Island and underlying the 

 bluff strata. This is its most southei'n 

 e.xposure. Rising as one proceeds north- 

 ward, it becomes more or less abundant 

 throughout all of the uplands of the 

 Slate. 



GRAND GULP GROUP. 



N'orth of the sands or gravels which 

 border the pine flats and prairies of this 

 >5tate occur the grand gulf formation. 

 Rising in height northward, the clays 

 and sandstones of this formation form a 

 prominent hilly belt, running across the 

 State through the parishes of Vernon, 

 Sabine, Natchitoches, Grant and Catahou- 

 la, terminating in the last parish at 

 Sicily island. I.,oug-leaf pine mark the 

 boundaries of this section, as well as a 

 similar section in eastern Louisiana. 



VJCKSBURG AND JACKSON GROUPS. 



North, and parallel with the transverse 

 ridge just described iu the parishes of 

 Verilou, Sabine, Natchitoches, Grant, 

 AViun, Catahoula and Caldwell, occurs a 

 narrow belt, within which the calcareous 

 marls and limestones of these groups 

 approach the surface, giving occasional 

 calcareous prairies. It terminates in the 

 high bluffs on the Ouachita River, at 

 Columbia, Caldwell parish. This belt is 

 about thirty miles wide. 



So far these strata appear to have a 

 general southward dip. but north of this 



prairie the stratiflcation conforms to the 

 calcareous ridge, or backbone, already 

 described and which originally determined 

 the divide between the Red and Ouachita 

 rivers. In northwestern Louisiana, cov- 

 ering the parishes of Caddo, De Soto, 

 and parts of Rienxille, Dossier and Sa- 

 bine, occur 



THE LOWER LIGNITIC 



rocks, risiiig conformably against this 

 cretaceous ridge. In inis section are the 

 most prominent .lignite beds of the 

 State. Agai.nst this is superimposed the 

 Marine Claiborne, which ocCui)y portion's 

 of liossier, Claiborne, Webster, liienville 

 and Natchitoches. Here the calc.-treous 

 and green sand marls abound, which, 

 under proi)er conditions, may be advan- 

 tageously used as fertilizers. 



TUB UPRER LIGNITIC 



i.s found underlying the parishes of Clai- 

 V)orne, Union, P>icnville, Jackson, Lincoln 

 and jiarts of Morehouse, Ouachita and 

 Caldwell. 



Superimposed over these last three 

 formations, stretching over the entire hill 

 portion of North Louisiana, is the forma- 

 tion known locally as 



THE ARCADIA CLAYS. 



In Webster and Bossier it has the larg- 

 est surface exposure, forming the soils 

 of the flats of these parishes. It is also 

 fully developed in every creek bottom in 

 this section. 



I'.ut while these formations underlie the 

 sections given, the surface exposures are 

 of limited areas, taking but little part 

 in the formation of soils Nearly Lhe en- 

 tire upland of tlie state has for its sur- 

 face covering the stratifled drift already 

 mentioned or the red, saudy clays. The 

 latter constitutes the chief material of the 

 soils of the hills of north Louisiana, and 

 as fiuch obscures, except in ravines aud 

 cuts, the geological formations given. 



RIVERS AND WATER COURSES. ^ 



No state in the union has so much al- 

 luvial lands or so many miles of navigable 

 waters. The widest part of the flood 

 plain, as well as the delta of th> j\iis- 

 sistsippi river, lies within its border. The 

 alluvial and marsh lands derivable from 

 this river are over 13,tX)0 square iniles. 

 The bottoms of the Red, and its tribu- 

 taries before it enters this valley, about 

 170U, the marsh lands west of the della 

 about 4000, other alluvia! and swamp lands 

 about 000 square miles, making in the 

 aggregate a little over 10.000 square miles 

 of alluvial laud, or nearly one-Iialf of the 

 6t.ire. 



The Mississippi and the Red are the 

 i-hief drainage channels of the state, and 

 alir.dst all of the larger stre:ims of these 

 'basins diverge from them, aud hence, arc 



called bayous. Before the days of 

 levees they formed so many channels, or 

 outlets f<ir the escape of water in 

 floods. Such a network of connections 

 has thus been formed that it is now dith- 

 cult sometimes to trace the course of 

 an individual stream. As a rule, some 

 large bayou flows al.ong the edge of the 

 bottom plain. Bayou Jiacon is on the 

 west of the Mississippi flood plain, Ouii- 

 chita river on the extremt> west <>f the 

 central plain, bayous Boeuf, Ci)codi'ie and 

 Teehe on the west of the Hood plain of 

 the Uort river. In north Louisiana the 

 rivers follow the trend of the subterra 

 nean rocks. In the east they flow soutli- 

 eastorly in the Ouachita and southward 

 into the Red. In the oxtren)e south 

 tlif/se west of Mississippi flow southw.ird 

 into the gulf; those east, southeast, into 

 the lakes. 



