GEOLOGY OF THE MERRIMACK DISTRICT, 5/1 



is upon Rattlesnake hill, where it has been extensively quarried. The 

 south-western limit is placed in the south-west corner of the town of 

 Concord. It is exposed at the cross-roads east of Great Turkey pond, 

 east of the smaller one, and from Millville across to the western limits of 

 the thickly settled district near the Asylum pond. A massive gneiss 

 flanks it on the west, at Millville. It crops out west of the railroad, in 

 the south-east part of the town, with north-westerly dipping seams ; and 

 occasionally in the city proper, as seen in the excavations for laying 

 the water-pipes on Tremont street, near the state prison. On the road 

 to Penacook lake the ledges crop out just beyond the sharp southerly 

 turn of the road half a mile west from Horseshoe pond. Near Little 

 pond the same kind of ledges seem to run N. 20° E. The southward 

 continuation of these rocks is quarried near W. M. Fox's, where the most 

 prominent seams dip 80° S, 70° E. In the other direction the rocks 

 continue into the hill, where most of the quarrying is done, and the same 

 ledge continues through to West Concord. West of Penacook lake is a 

 ridge of ferruginous rock with quartz. There seems to be a recurrence 

 of the Concord granite, or something very much like it, on the north-west 

 continuation of Pine hill, near A. C. Carter's ; and there are white ledges 

 between L. F. Ferrin's and the bend in the Concord & Claremont Rail- 

 road. This mass has not been observed for more than two miles in length, 

 unless the unusual prevalence of boulders of this material indicates out- 

 crops near D. Dimond's. At Contoocookville is still another mass of 

 Concord granite, perhaps a mile long. It does not appear to advantage 

 upon the map, on account of the overlying alluvium. 



At A. A. Blanchard's, beyond West Concord, the rock is more gneissic 

 in appearance, dipping south-east, and must constitute the outer edge of 

 the granite. On the east side of the Merrimack, all the ledges seen north 

 of East Concord are of different character, but the granite makes up the 

 mass of some hills in the west edge of Loudon, The immense sand plain 

 of eastern Concord prevents us from knowing whether the granite is con- 

 tinuous beneath it from the city to Loudon village, the presumption being 

 against a connection. 



The most extensive quartz range known in the Montalban runs through 

 Concord. It may be known first at the south-east corner of Warner, in the 

 small area noticed there on page 534. More likely there is a synclinal 



