5O PHYSICAL GEOGRAPHY. 



and Surry, separated by a wide band of gneiss from the central group. 

 As the same rock appears in Grafton and Newport, fifty or sixty miles 

 farther north, it is likely the same arrangement continues past the centre 

 of the state ; while the descriptions of my father, in the final report on 

 the geology of Massachusetts, speak of a white quartzite having the same 

 relations, midway through that commonwealth. Neither this, nor the 

 band of porphyritic gneiss mentioned as passing nearly north and south 

 from New Hampshire to Connecticut, on the meridian of Ware, was 

 represented upon his map, as their importance was not appreciated. 



In the report for 1872, a map of the southern part of New Hampshire 

 was presented for the purpose of showing the course of these quartzite 

 bands. The following statements were made respecting them : 



Our map shows two nearly parallel ranges of quartzites, the one extending from 

 Allenstown to Mason, and the other from the same town to Temple. Diligent search 

 has failed to reveal any traces of these bands beyond Allenstown, which surely belong 

 to them. Inasmuch as the accompanying gneisses also terminate, both those included 

 between the ranges, and the crumpled granitic gneiss to the south-east, and the mica 

 schists beyond seem to have taken a northerly course, we conclude that the continua- 

 tion of all those strata is concealed by the overlying blanket of mica schist. The 

 map shows how completely these bands are interrupted by the newer schists. Nothing 

 has yet been suggested to account for the termination of the quartzite bands in Temple 

 and Mason. Further search may reveal them on the same line in Massachusetts. 



The map shows these quartzites in Richmond, Keene, Surry, and Grafton, on the 

 west side of the porphyritic range. We have not yet been able to trace them out in 

 that part of the state. These ranges have been seen in Massachusetts, especially in 

 New Salem. Their occurrence in two bands on both sides of the main anticlinal will 

 furnish us the general clue to the stratigraphical structure of the gneiss, besides making 

 plain the line of the granites and soapstone, for there is a range of the latter mineral 

 accompanying the Keene quartzites. It will be observed that the latter curve around 

 the older porphyritic rocks of Swanzey. 



It is almost exciting to follow the hills of this rock through the towns. They can be 

 seen miles away, being as white as snow. The following are the most notable hills 

 along its course : In East Concord, Oak hill ; West Concord, Pine hill ; on the Temple 

 range, the foundations of the upper railroad bridge, and the Pinnacle in Hooksett ; 

 the hill of quartz quarried for the manufacture of glass in Lyndeborough, and a long 

 ridge in Temple extending north-easterly from the village ; on the Mason range, a 

 high hill north-east from East Wilton ; the north-east corner of Amherst ; and Campbell 

 hill in Hooksett. The ranges are 6.20 miles apart in New Boston and Bedford, 

 narrowing to 3.12 in Hooksett, and 5 miles in Wilton. The most remote localities in 



