548 STEVEXSOX— THE FORMATION OF COAL BEDS. [Nov. i, 



covered to a depth of 20 to 100 feet with a reddish-yellow semi- 

 plastic earth, frequently marly with calcareous nodules, due to 

 percolation of calcareous water from the rivers. No stones or 

 pebbles are seen in this deposit, but it grows more sandy toward the 

 west. Church believes that these Pampean deposits were laid down 

 in a sea, 1,400 miles long and with an area of about 600,000 square 

 miles, this being the region now drained by the Paraguay and its 

 tributaries, the Pilcomayo, Bermejo and Salado at the west, and the 

 Lourengo, Parana and Uraguay at the east. To this area he would 

 add about 115,000 square miles at the northwest, now drained into 

 the Amazon by the Madeira River, the areas being connected by a 

 narrow strait. This inland sea communicated with the ocean near 

 the present outlet of Rio de la Plata, but the area of deposit ex- 

 tended farther southward, almost to the latitude of Bahia Blanca. 

 The Pampean beds have been displaced and made irregular in some 

 places, but they are undisturbed in the southern portion of this 

 Gran Chaco region between the Bermejo and Salado Rivers. 

 Church estimates the present area of the muds at about 400,000 

 square miles and believes that they were deposited in shallow water. 

 The rivers are all very crooked, have very uncertain channels, at 

 times deserting the old course for a new one several miles away. 

 They frequently divide and subdivide so as to break the plain into 

 narrow but extensive islands. 



j^gj-j-ioi ]^^g described the central part of the plain. The Ber- 

 mejo River, entering from the west, is 1,000 miles long but very 

 tortuous, the distance in direct line from its source to the Paraguay 

 River being not more than 450 miles. The speed is 4 to 5 miles 

 per hour and an enormous amount of solid matter is carried in 

 suspension — whence its name, " The Red." In flood time, it is 

 almost liquid mud. The rainfall is very heavy and the maxima are 

 marked by inundations covering immense areas to the depth of 

 several feet. Areas subject to inundation are characterized by palm 

 forests, and one may always see on the trees a dark line at 3 to 5 

 feet above the ground, marking the flood level. The surface layer, 



'"J. G. Kerr, "The Gran Chaco," Scot. Geogr. Mag., Vol. VIII., 1892, 

 PP- 74-77- 



