320 



STRATIGRAPHICAL GEOLOGY. 



by Mink pond. Some of our specimens suggest the existence of the 

 Coos slates to a limited amount upon Walker hill and its neighborhood, 

 the continuation of the Eustis Hill range from Littleton lying between 

 the Bethlehem and Swift Water series. The last that can be depended 

 upon is at P. H. Padelford's, at the south line of Littleton, 



Swift Water Series. 



While occupied in studying the geology of the gold field, I found a set 

 of specimens which could not be readily referred to any of the series that 

 have been mentioned. They approximate nearest to the 

 Lisbon group, and occupy the territory east of that for- 

 mation. Its whole extent from Haverhill to North Lis- 

 I bon (Fig. 28, p. 278) shows the position of this series 

 ^, in the typical section, crossing the east part of the field 

 I at Lisbon village. The combined thickness of the quart- 

 S zites, sandstones, hornblende schist, and slates amounts 

 ^ to 4400 feet. 



I Our attention was directed to this group partly by the 

 s slate bands, and partly by a nondescript conglomerate 

 ". adjoining it, particularly noticeable a mile and a half 

 I north from Lisbon, west of Mrs. A. Bishop's, on the 

 I north-west side of the river. The pebbles are not dis- 

 I cernible till the rock has been weathered nearly white, 



o 



^. and even then it is difificult to understand their charac- 



^ ten This band is not more than fifty feet thick. 



« Following up the Wild Ammonoosuc river in Bath, 



S there is a characteristic representation of this series of 



'^- strata; and our name is derived from that of a small 



I village on its banks. The facts given are chiefly from 



I the notes of Mr. J. H. Huntington. The Lisbon group 



to 



I seems to extend up this stream for more than a mile 

 above its mouth, judging from its general distribution. 

 A little above a starch factory (Fig. 35) there are strata 

 of micaceous conglomerate, of gneissoid aspect, dipping 

 40" N. 65^ W. The slate, or the continuation of the Lisbon band, is half 

 a mile above the factory, and it dips 65° N. 82° W. Less than half a 



