Surficial Geology of the Jefferson 7.5' Quadrangle, New Hampshire 71°30'0"W 71°27'30"W 71°25'0"W 71°22'30"W 44°30'0"N 44°30'0"N 32 td td td 180 td Pt DESCRIPTION OF MAP UNITS Ha Pg 220 Pt Stream or lake 36 Artificial fill— Earth m ate rial of various sorts, use d as road fill. Shown af Pt 110 7 only whe re thick e nough to alte r the top ograp hic m ap contours. 50 td Qls HOLOCEN E DEP OSITS 122 Stream alluvium— Sand , grave l, and silt d e p osite d on the flood p lains of Qf Ha Pg Qf td stre am s. Unit m ay includ e som e we tland are as. 24 Wetland deposits— P e at, m uck, silt, and clay. De p osite d in p oorly d raine d 20 Hw 3 8 Qfb1 are as. 6 6 Qfb1 120 QUATERN ARY DEP OSITS td 3 22 131 Qfb2 Israel Valley deposits — Unclassifie d glacial to p ostglacial sand and Qirvd grave l in the Israe l Rive r valle y. Most of this unit occurs in the ad jace nt Mount Dartm outh q uad rangle to the south (Fowle r and Barke r, 2015). Qfb1 td Stream terraces — Sand and grave l d e p osite d on form e r flood -p lain td Qst Pg surface s along the Israe l Rive r and othe r stre am s. Qfg Fan deposits (undifferentiated) — Alluvial fans form e d along the m id to Qf Pt Qls lowe r re ache s of stre am s that d rain the ste e p m ountain slop e s which occur ove r m uch of the m ap are a. Typ ically com p ose d of ve ry coarse , p oorly- sorte d p e b b le -b ould e r grave l and m inor sand . Y ounge r fans d e p osite d b y Bunne ll Brook. Qfb2 Qfg 75 40 Old e r fans d e p osite d b y Bunne ll Brook. 8 Ha Qfb1 Garland b rook fan. 8 td Qfg 14 Stag Hollow Brook fan. Qfsh 15 19 Pt 9 9 Landslide areas— Zone of single or m ultip le slop e failure s, includ ing: (1) Qls 25 5 cluste r of se ve ral ve ry ste e p d e b ris avalanche tracks on the south face of the 44°27'30"N 44°27'30"N 20 rid ge b e twe e n Mount Starr King and Mount W aum b e k in Je ffe rson: and (2) 105 80 22 zone of slum p m ove m e nts with arc uate he ad scarp s along the up p e r p art of Bunne ll Brook in Lancaste r and Kilke nny; and (3) a rockslid e or d e b ris avalanche on the southe ast e nd of Te rrace Mountain in Kilke nny. Avalanche 8 d e p osits m ay includ e variab le p rop ortions of re worke d till and colluvium Pt 14 toge the r with b e d rock b locks from local outcrop s. Slum p d e p osits m ay 12 includ e re worke d till, colluvium , stre am grave l, and fine -graine d se d im e nts d e p osite d in ice -d am m e d p ond s. Ad d itional land slid e s are like ly to occur in re m ote m ountainous te rrain of the W hite Mountain N ational Fore st. 3 31 P LEISTOCEN E DEP OSITS 29 Glacial Lake Israel deposits — Glacial Lake Israe l d e p osits. Sand and Pli grave l d e p osite d into Lake Israe l, which e xiste d whe n the lowe r Israe l Rive r 21 valle y was d am m e d b y the re ce d ing glacial ice m argin. The up p e r surface s of the se d e p osits we re at le ast p artly te rrace d as the lake le ve l d rop p e d and the p ostglacial Israe l Rive r b e gan to re work and cut d own through the td glacial lake se d im e nts. Sm all are as of sand and grave l of p rob ab le glacial origin, b ut whose Pg d e p ositional e nvironm e nts are unknown. Ice-contact deposits — Sand and grave l d e p osite d b y glacial m e ltwate r td Pgi stre am s in contact with re m nant m asse s of stagnant ice . Occurs along Big Le d ge Brook in Rand olp h. 20 Eskers — Rid ge s of grave l and m inor sand d e p osite d b y m e ltwate r stre am s Pge in sub glacial ice tunne ls. Eske rs occur in the Israe l Rive r valle y in Qls Je ffe rson, and on the lowe r southe ast slop e of P liny Mountain in Rand olp h. 21 10 End moraine complex — Are a of short m oraine rid ge s and till hum m oc ks Pemc 1 d e p osite d at the m argin of the Laure nd tid e Ice She e t as it re ce d e d north- 3 1 4 1 2 3 1 6 northwe st from the Israe l Rive r valle y. In this are a, m any rid ge s and 15 1 12 5 3 18 1 2 5 5 4 5 16 5 hum m ocks of stony till are inte rsp e rse d with low are as includ ing p atche s of 13 6 we t ground . Qf 8 12 Till — Loose to ve ry com p act, p oorly sorte d , m assive to we akly stratifie d Pt m ixture of sand , silt, and grave l-size rock d e b ris. De p osite d d ire ctly from 9 Pt glacial ice . May includ e le nse sm of wate rlaid sand and grave l. 40 8 Thin-drift areas — "td " ind icate s are as whe re outcrop s are com m on and /or 60 td surficial se d im e nts are infe rre d to b e ge ne rally le ss than 10 ft thick. Map p e d 7 p artly from air p hotos and LiDAR im age ry, e sp e cially in re m ote are as, 56 36 whe re thin-d rift are as are like ly m ore e xte nsive than shown he re . 20 18 44°25'0"N 44°25'0"N × Qf × Pt 24 Pge × × × × 24 × × 21 × Pge × EXPLANATION OF MAP SYMBOLS × × × × × × × × Contact Bound ary b e twe e n m ap units, d ashe d whe re infe rre d . × 17 td × td × Water well × × Pgi Lab e l ind ic ate s d e p th to b e d roc k in fe e t. × Qf 7 5 Pt Bedrock outcrop Ind ivid ual b e d rock outcrop s, com m on in thin d rift. × × Pge × 77 × Hw × × × Glacial striation Arrow shows glacial ice -flow d ire c tion infe rre d Qst × 16 26 × from striations on b e d roc k. Dot m ark p oint of × 14 locality × 4.5 td ob se rvation. N um b e r is azim uth (in d e gre e s) of flow × × 39 5 (multiple present) 1 d ire ction. Multip le arrows ind icate site s with two or 20 30 1 45 11 m ore striation se ts d ue to changing flow d ire c tions. 6 12 Sp illway for Baile ys (Ba) Stage of glacial Lake Qst 12 9 Spillway 15 15 Ba Israe l - "339" is the ap p roxim ate e le vation (in Pemc 120 6 m e te rs) of the sp illway through which the lake 7 120 wate r e scap e d we stward through the Che rry P ond 17 82 are a and into the up p e r Johns Rive r (Lancaste r 8 68 q uad rangle ). 105 Pg Infe rre d shore line of glacial Lake Israe l d uring Pt Shoreline 26 Qf 210 Qfsh Baile ys Stage - Locate d ap p roxim ate ly, b ase d on the 30 339 m sp illway e le vation. 26 , Glacially Sym b ol shows axis of sm ooth till rid ge which has Ha streamlined till b e e n e longate d and stre am line d b y glacial ice flow. af ridge , Ha Pt Line m arks axis of till rid ge d e p osite d at the m argin 30 Moraine ridge Qst of the last glacial ic e she e t d uring a p ause in its re ce ssion. Qst Ha 35 Channe l e rod e d b y glac ial m e ltwate r stre am . Arrow 162 Meltwater channel Pli shows infe rre d d ire ction of form e r stre am flow.