marl·stone 
(märlstōn′)
(märlstōn′)n.
A rock containing clay materials and calcium and magnesium carbonates, with approximately the same composition as marl.
- counterperson
- counterplan
- counterplay
- counterplot
- counterpoint
- counterpoise
- counterpose
- counterproductive
- counterproductively
- counterprogram
- counterproposal
- counterpunch
- counterpuncher
- Counter Reformation
- counterreformation
- counterrevolution
- counterrevolutionary
- counterrevolutionist
- countershading
- countershaft
- countersign
- countersignature
- countersink
- counterspy
- counterstain