They are deposited over time, and often show layers which can be seen in cliffs.
Volcanic activity deposited lava over the area 1.8 million to 500,000 years ago.
In Arizona, dust is deposited each month at over four times that amount.
More than 180,000 savings clients had deposited over US$ 40 million with the bank by the end of the year.
The river overflowed its banks and chunks of ice were deposited all over the site.
A virtual bank is also a common feature, in which users can deposit currency and gain interest on it over time.
They deposit clutches of 50 to 75 eggs on vegetation or rocks over water.
The sums have been deposited over a four-year period.
As more and more soil deposited over them, they were compressed.
Two of them were particularly "dirty", depositing long-lasting radiation over the area.
