When the ice finally retreated it left deep deposits of boulder clay (or till) behind.
On the sea floor they form deep deposits of diatomaceous earth, which is mined for abrasives and filters.
When the glacier finally retreated they left deep deposits of boulder clay and glacial alluvium behind.
As the marshes evaporated, deep deposits of rock salt were formed.
Lower-lying areas, as in Happy Valley, have deep deposits of clay, silt and sand.
Greenops can also be found in deep marine deposits, but there it is fairly rare.
Fore-arc basins are filled with deep marine deposits and thick sequences of turbidites.
The industry has also spent decades experimenting with ways to recover bitumen from deeper deposits.
In deeper deposits he uncovered human teeth and remains left there by Stone Age people some 40,000 to 80,000 years ago.
Ammolite mined from deeper deposits may be entirely smooth or with a rippled surface.
