COAL MEASUEES OF THE BEDHAM QUADEANGLE. 187 



did Permian or later strata ovei'lie tliem ? There is a chance that in the 

 center of some one of these synclinal areas higher beds than have here 

 been recognized may be discovered. It is indeed possible that the whole 

 of the Dighton series is of Permian age. 



The contemporaneous flora and fauna of the conglomerate are as yet 

 practically unknown. The brachiopods and worm burrows reported in the 

 quartzite pebbles belong to the upper Cambrian fauna, (See p. 109.) 



EXTEKSIOIS" OF THE COAIi MEASURES IS'ORTH AKD EAST OF TAUNTOIST. 



Having described a typical area of the Coal Measures and the over- 

 lying conglomerates in a part of the basin where evidence of their structural 

 relations can be had, it is now purposed to describe the eastern extension of 

 these rocks, where the structure is less well understood. For convenience, 

 the order of presentation which is suggested by the mapping of this portion 

 of the field in sheets of the atlas folio will be followed, for the reason that 

 within the limits of these maps, comprising the Dedham, Abington, Middle- 

 boro, and a part of the Taunton quadrangles, the exposures of strata are too 

 few in number and extent to permit any systematic account of the stratig- 

 raphy. These rocks have been described with more fullness than their 

 importance apparently deserves, partly for the reason that they have not 

 been heretofore described, and partly because they are the sole indications 

 of the under geology of the eastern part of the Cai^boniferous field. 



DEDHAM QUADRANGLE. 



The Carboniferous rocks of the main basin cover the larger part of 

 the southern third of this quadrangle. After we pass southward and 

 geologically above the rocks immediately along the border, outcrops 

 are too few to give more than a very general view of the stratigraphy. 

 The Coal Measures are present in Mansfield and West Bridgewater, and 

 probably underlie the intermediate towns. The surface, outside of the 

 glacial sand plains, is strewn with flaggy micaceous and feldspathic sand- 

 stones suggesting arkoses, which agree in character with some of the out- 

 crops. A few conglomerate bowlders of the gray series occur, but never in 

 the abundance which characterizes the proximity of the coai'se Dighton 

 group in other parts of the field. There is also absent the hilly and rough- 

 ened topography which accompanies these latter beds when they occur in 



