GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 20/ 



tine of a very dark color, often asbesliform in the joints, and appearing to form a syn- 

 clinal axis. It is followed on the south-east by a granular crystalline rock somewhat 

 coarser than that on the north-east, but otherwise similar. This rock is so cut by joints 

 that it is impossible to determine the dip, though the strike corresponds with the gran- 

 ular crystalline rock north-east of the serpentine. 



Leaving the river and following the old road, the next outcrop is a dark green crys- 

 talline rock, succeeded by quartzite that dips 63° S. 20° E. This is followed by a 

 breccia composed of greenish slate, quartzite, and serpentine, and also what appear to 

 be reddish grains of felsite. The breccia seems to be composed of rocks found on 

 either side of it. It is followed on the south-east by a quartzite that dips 75° S. 30"^ W. 

 At Eustis village, extending a mile north-west and three and a half miles south-east, 

 there is a band of tender fissile slate, generally of a greenish-gray color, but having 

 bands of light purple ; and south-east of the village are bands of quartzite. This slate 

 forms a distinct synclinal axis. On the RIagalloway river we have granular schistose 

 rocks, quartzites, serpentine, and slate. The similarity of these to those on Dead river 

 makes it quite probable that the latter are a continuation of the former. Between 

 Eustis village and Mt. Bigelow there is a greenish chloritic rock that seems to pass 

 into porphyritic gneiss. This rock occupies a large area in Dead River plantation and 

 Flagstaff. Since a similar rock was seen in Range 6, Lot 3, and north-west at Attean 

 and Wood ponds, a continuous band may extend thirty miles northward. There is a 

 striking similarity in this rock to one found in Northumberland, N. H., and southward. 

 Here, as at Littleton, N. H., there is a band of Helderberg limestone containing corals 

 that are remarkably distinct. The rock where the fossils are most abundant outcrops 

 on an island in Flagstaff pond. On the west peak of Flagstaff mountain there is a 

 band of limestone, but the fossils are very obscure. South of the green chloritic gneiss 

 there is a mica schist or imperfect gneiss that resembles very closely the White Moun- 

 tain series. On the west peak of Mt. Bigelow the dip is 50° N. On the ridge extend- 

 ing from Mt. Bigelow east, where the road passes over it in Range 11, No. 2, the rock 

 is mica schist. It dips 60° N. 5° W., and carries an abundance of small crystals of 

 andalusite. These rocks rest on a porphyritic gneiss that outcrops a few rods south of 

 the height of land. The gneiss resembles the rock of the basin north-west in the 

 valley, and is followed on the south in New Portland by a granitoid gneiss that resem- 

 bles very closely that associated with the gneiss in the vicinity of the White Mountains. 



Adopting the conclusions derived from our study of the rocks in northern New Eng- 

 land, we think the porphyritic gneiss south of Mt. Bigelow is the oldest of all the rocks 

 enumerated. This area is represented in the north-east corner of the map, page 512, 

 Volume I. The gneisses of Mt. Bigelow and the ridges eastward abound in crystals 

 of andalusite, and appear to belong to the White Mountain series, and to rest upon the 

 porphyritic variety. The series of chloritic and talcoid schists, quartzites, and serpen- 

 tines appears to be still more recent, and to be allied to the Huronian system. The 

 granite and gneiss from the lake outlet on the east to the Megantic basin on the west, 

 may be older than the Huronian upon both flanks. 



