276 BOARD OF AGRICULTURE. 



abounded. But this year, after a further examination of this rock, 

 we shall call it Argillo-viicaceous schist, coloring it on the map as 

 mica schist. Inspection of all the varieties discloses the presence 

 of minute scales of mica. They are found even in the roofing slate 

 of Brownville, which is associated with the schists, and by their 

 presence throw light upon the mineral structure of the whole series, 

 showing it to be micaceous rather than talcose. What we described 

 as one formation of clay slate last year, we now divide into two, 

 the clay-slate proper and the Argillo-micaceous schist. 



The manner in which the boundaries of this sub-division were 

 suggested to us, is quite interesting and valuable, as indicating the 

 direction to be taken in studying these rocks in future. We pos- 

 sessed a series of observations of the position of the strata, cross- 

 ing tho whole argillaceous belt in several places, and mostly 

 radiating from Bangor. Upon comparing these sections with one 

 another, we found them to agree essentially at the same distances 

 from Bangor, or from the south-east side of the formation. The 

 material from which we drew is mostly contained in our last year's 

 report. We there described a section from Bangor to Patten ; an- 

 other branching off at Mattawamkeag up the East Branch of the 

 Penobscot ; another from Bangor to Brownville. This year we 

 explored one from Bangor to Moosehead Lake ; and also another 

 from Shirley to Brighton. At Bangor the dip is north-westerly, 

 but at a few miles distance on every route it changed to south- 

 easterly, thus making a synclinal axis. This synclinal line, then, 

 we -found to run, (so far as our meagre observations allowed us to 

 judge,) from the mouth of Sunkhaze stream in Milford westerly 

 through the north parts of Oldtown and Pushaw Lake, thence curv- 

 ing south-westerly it passes west of Kenduskeag village, and 

 probably to Carmel, and N. E. Dixmont. Upon the east side of 

 this line the dip is north-westerly, on the line of our principal sec- 

 tion, as far as Ilolden center ; and upon the west side the dip is 

 south-easterly as far as tho north part of Charleston, thus making 

 an enormous basin, twenty-nine miles wide, whose thickness must 

 be seven miles on the lowest estimate. The anticlinal line west of 

 the first synclinal was first observed near Passadumkeag village, 

 and can be traced westerly through Edinburgh, Lagrange and 

 Bradford, till we find it rising into a range of mountains, which 

 continue through Charleston, Garland and Dexter. This is a 

 very distinct axis, as it is coincident with a mountainous range 



