CONTENTS. 7 
< 2.' J Page - 
'ontmued. 
nd-cement materials — Continued. 
Permian limestones 169 
Cretaceous limestones 169 
md-cement industry 170 
171 
Trenton limestone 171 
Cincinnati or Hudson group 172 
Mississippian ( " Lower Carboniferous " ) limestones 173 
Pennsy 1 vanian ( ' ' Coal Measures' ' ) limestones 1 74 
Louisiana 175 
Maine 176 
Maryland- 179 
Trenton limestones and adjacent clays 179 
Helderberg limestone and adjacent clays 183 
Greenbrier limestone and adjacent shales 186 
Massachusetts 189 
Michigan 189 
Portland-cement materials 189 
Limestones 190 
Dundee limestone 190 
Traverse group 192 
' ' Michigan series " 193 
Marl deposits 194 
Shales and clays 198 
Cold water shales . 199 
Antrim shales 200 
Saginaw formation 201 
Clays 202 
References 205 
Minnesota 206 
Mississippi 206 
Mississippian ( ' ' Lower Carboniferous ' ' ) limestone 206 
Cretaceous ( Sel ma chalk ' ' Rotten limestone " ) 207 
Tertiary limestones ( Vicksburg limestone) 218 
Missouri 219 
Portland-cement materials 219 
Trenton limestone 221 
Late Ordovician shale 222 
Devonian formations 222 
Mississippian ( ' ' Lower Carboniferous ' ' ) limestone and shales . 222 
Pennsyl vanian ( ' ' Coal Measures' ' ) limestones and shales 225 
Loess and surface clays 226 
Portland-cement industry 227 
Montana by W. H. Weed. 227 
Nebraska 229 
Carboniferous formations 229 
Niobrara and Benton formations 230 
Pierre clay 230 
Nevada 231 
New Jersey 
Portland-cement materials 231 
Limestones of Warren and Sussex counties 232 
Hardyston quartzite 232 
