GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 325 



west side, near the house of P. Ash. Ilelderberg rocks may appear next, 

 which I will notice hereafter. The following is the order of rocks seen 

 from D. Richardson's house, up a deserted road towards Sugar hill : At 

 the house, Helderberg limestone ; measures concealed across the railroad 

 and field; at the base of the hill, conglomerates, one variety holding stones 

 of the size of a hen's egg, and the other indurated and composed of small 

 fragments, together with mica schist, both the same with the rock expos- 

 ures in the South IJranch. ]5ands of quart/Jle accompany tlic schist, and 

 all dip 85'^ north-westerly. Close by these schists, and next in order, arc 

 ledges of the hard Huronian diorites. On climbing the hill for half a 

 mile, no other ledges were seen. This order of rocks agrees with that 

 figured in one of the Helderberg North Ij"sl)on sections. 



Taking the west side of the river, the following are the rocks seen, 

 beginning with Chase's hornblende. It appears on the river bank oppo- 

 site a curious sheep-house, shaped like an old-fashioned straw beehive, 

 near the house of P. Ash. Then we find the slate band. Between J. 

 Dexter's, 2d., and D. S. Richardson's, arc schists referred heretofore to 

 the Swift Water series. Near a school-house is a hard quartzite, like 

 some Huronian varieties. There is nothing else till we reach the con- 

 glomerate under the bridge crossing to the station. 



On the road from Walker hill over to the south part of Littleton arc 

 numerous greenish schists, with large, pebbly grains of quartz. The 

 same occur in large amounts to the north-west towards the house of P. 

 K. Corey. There is quite a broad band, — say a mile wide between the 

 slates and the gneiss in the north part of Lisbon, — which belongs to the 

 Swift Water member of the Huronian. In South Littleton this mostly 

 disappears beneath the alluvium of the Ammonoosuc, and may connect 

 with the narrow Huronian band east of the Helderberg by Parker's river. 

 By such a reference of these strata it is easy to understand the relations 

 of the several formations along the Ammonoosuc valley. There will be 

 further reference to them in the description of the sections crossing Blue- 

 berry hill under the next topic. 



IlELDERnERG. 



There are three divisions of the Helderberg rocks of Littleton. The 

 lowest member is quartzitc or buhrstone ; the middle is a limestone ; 



