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REVIEWS 287 
planalto, and its steep coastal border which constitutes the Serra do 
Mar. The region was baseleveled in the late Mesozoic, and the sum- 
mits of the Serra do Mar which rise above the plateau level were prob- 
ably more resistant granitic bosses which had not been reduced to the 
base plain. Uplifts in Tertiary and subsequent times have contributed 
to the present elevation and to the existing status of erosion. 
The bulletin closes with a note on the changes of level on the coast 
of southern Chile. Starting out with the intention of studying the 
nature of the Pleistocene and Recent uplifting of the Chilean coast, 
first described by Charles Darwin, Woodworth failed to find good evi- 
dence of any extensive rise of the coast in Quaternary times. A late 
Pliocene or early Pleistocene uplift of about sixty feet at Valdivia, a late 
Pleistocene uplift of forty-five feet at Concepg¢ion, and a recent rise of 
lesser magnitude were indicated by these studies. 
Roc. 
“‘Formation of Coal Beds.” II. By JoHN J. STEVENSON. Proc. 
Hu eyi..soc., Vol. L, No. 202, 101. 
The author of this article has prepared a careful survey of the litera- 
ture bearing on the origin of coal beds. He has presented much data 
regarding the origin and character of transported organic matter and 
discussed the significance of floods and torrents as eroding and transport- 
ing agencies. There are three major divisions of the subject: 
t. Rainfall barely disturbs the cover of litter in a forest and the 
latter is practically uninjured by the heaviest rainfall. Rainfall does 
not remove soil covered by vegetation unless this mantle is ruptured. 
Torrents produce but slight effects upon the rocks or vegetation over 
which they flow unless they carry considerable débris; trees of small 
and large diameter resist mountain torrents that are even loaded with 
coarse débris. Where the torrents come from regions having a good 
mantle of vegetable matter they are practically free from inorganic load. 
2. Descriptions of peat deposits are included under this head and data 
from widely scattered regions are brought together showing the geographic 
and stratigraphic position of the beds, the botanical constitution, the 
appearance, thickness, and degree of consolidation. Peat consists of more 
or less altered plant material whose organic texture is recognizable and 
of an inclosing substance evidently derived from complete decomposition 
of the plant tissues. This is all more or less mixed with sedimentary 
sand, clay, or calcareous matter. Peat always contains a large amount 
of water. The fact is pointed out that peat does accumulate in the tropics 
