ABSTEACTS: GEOLOGY 225 



After the disappearance of the Wisconsin ice the land seems to have 

 stood somewhat higher than at present, as indicated by the buried and 

 submerged peats along the coast, the difference in level being perhaps 25 

 feet. This would indicate the elevation of 45 feet in late Wisconsin or 

 post-Wisconsin time. In recent years there has been depression esti- 

 mated at the rate of 6 inches to 2 feet in one hundred years. A sinking 

 of not more than 25 feet apparently has occurred since the beginning of 

 this movement. Alfred H. Brooks. 



GEOLOGY. — Resins in Paleozoic 'plants and in coals of high rank. 

 David White. U. S. Geological Survey Professional Paper 85-E. 

 Pp. 97, with plates. 1914. 



Lumps of resin of different kinds are present nearly everywhere in 

 coals of low rank, such as lignites and sub-bituminous coals, the resins 

 being very abundant and conspicuous in some beds. The amount of 

 microscopic resin probably far exceeds that visible to the naked eye. 



The presence of resins in Paleozoic coals, which has been seriously 

 questioned, the available information being limited, is set at rest by the 

 observation of small lumps found in coals of a medium bituminous rank 

 in Iowa, Illinois, and Indiana. The examination of the woods and pet- 

 ioles, found under conditions favorable for examination in Paleozoic 

 coals, indicates that plants secreting resinous substances were not only 

 present but common in the Carboniferous flora. Therefore, absence of 

 resins is not distinctive of Paleozoic coals. 



Observations in the Cretaceous and Tertiary coal fields indicate that, 

 in the processes of metamorphism which have converted lignites and 

 other low rank coals to coals of higher rank, the lump resins are de- 

 formed, discolored, and carbonized, with probable high losses of volatile 

 matter, as the coals are brought to a moderately high bituminous rank 

 corresponding to a percentage of about 65 per cent of fixed carbon in 

 pure coal, the megascopic resins being very rarely recognizable to the 

 unaided eye when the coal has reached the good cooking rank. It is 

 probable that the resins undergo minor chemical change soon after 

 deposition with the organic debris from which the coals are formed. 



D. W. 



