128 
Gabbros, 13, 36 
Genesee river, 27, 83, 113 
Genesee shale, 12, 56 
Geolagy, defined, 7 
Geologic time scale, 11 
Geotogy, defined, 7 
George, Lake, 104 
Georgian slate and quartzite, 13 
Glacial boulders, 94 
Glacial lakes, extinct, 105 
Glacial period, 87-117: duration, 114 
Gorges, 107 
Gouverneur marble, 30 
Grabau, A. W., cited, 82, 113 
Granite, 13, 34 
Great Lakes, history, 96-101 
Great Lakes region, upward move- 
waSmMc, WU 
Green mountains, 47, 48 
Greenwood lake, 104 
Grenville formation, 29-33; distri- 
bution, thickness, and age, 31; up- 
lift, 37 
Grenville metamorphosed sediments, 
13 
Grenville ocean, life in, 32 
Ground moraine, 94 
Guelph dolomite, 12, 54 
Gulfs, 112 
Hamilton shale, 12, 56 
Hans creek, III 
Havana glen, 114 
Helderberg escarpment, 
55 
Helderberg limestone, 12, 55 
Highlands-of-the-Hudson, 24, 48, 
49; Grenville formation, 20, 31; 
igneous activity, 36 
Hudson river, 26, 79, 84; lower 
channel submerged, 116; pregla- 
Clalessuian 
Hudson river shales and sandstones, 
46 
Hudson valley, inner gorge, 85 
Hudson valley province, 23-25 
1, Aik, Fe, 
Ice age, 87-117; duration, 114 
Igneous activity, early Precambric, 
33-36 
NEW YORK STATE MUSEUM 
| Igneous rocks, 8, 13 
_ Illinois river, 99 
| Iroquois, Lake, 100, 
Iroquois beaches, 117 
I01l 
Jurassic period, 63, 64 
Kames, 95 
Kennyetto creek, 111 
Kettle holes, 93 
Labradorean ice sheet, 88 
Lakes, see specific names of 
Lakes, Great, see Great Lakes 
Lansing Kill lake, 106 
Laurentian granite, 34 
Laurentide ice sheet, 88 
Little Halls} 190)%20) As 7anor 
Little Falls dolomite, 13, 43, 44 
Little Falls gorge, 108 
Lockport dolomite, 12, 54 
Long Island, 116 
Long Island province, 25, 28 
Luzerne river, III 
Lyons Falls, 21 
Mammals, age of, 77 
Manlius limestone, 12, 54 
Maps, construction and uses, 118 
Marcellus shale, 12, 56 
Maumee, Lake, 98 
Medina sandstone and conglomerate, 
12, Bil, Gy 
Mesozoic, 61-76; drainage of New 
York in, 74-76; life of, 66-67 
Metamorphic rocks, 9 
Michigan, Lake, 98 
Miocene, 77 
Mohawk-Hudson basin, 26 
Mohawk river, 27, 80, 86; outlet, 101 
Mohawk valley, 80; faulted region, 
72; glacial history, 109 
Mohawk valley province, 19-21 
Mohonk lake, 104 
Mt Marcy, 34; altitude, 15 
New York City, 116 
New York State, recent elevation, 
116 
