Conglomerates.
Sedimentary rocks are formed when flowing water deposits sediment. They tend to have a rounded shape, because the flowing water smooths out their shape.
Not just any sand. Mortar sand. Mortar sand is a larger grain sand that has been washed and screened to remove any rocks or pebbles.
Breccia
gravel forms
At the mouth of a river, you would expect to find a mix of sedimentary rocks, such as sandstone, siltstone, and shale, that have been eroded and transported by the river. You may also find some rounded pebbles or cobbles made of harder rock types that have been carried downstream. Additionally, there could be some deposited sediments like sand and gravel.
top soil is sand nd subsoil are rocks mix with sand
If you mix cement ,sand and water you get mortar If you mix cement and stone pebbles or chips you get concrete Concrete.Sometimes gravel is mixed with it, too.
Conglomerates.
Conglomerates form from clastic sediments which are products of weathering, so, conglomeratic materials could be formed from any other rock type. Conglomerate itself is an Example of Mechanically formed Sedimentary Rock.
texture. These rocks, known as conglomerates, form when the sediments are transported and deposited by water or gravity, resulting in a mix of different sized particles. The large pebbles and stones in conglomerates give them a visibly coarse appearance.
Rocks can be formed by particles of pebbles, sand or shells creating sedimentary rocks. When molten rock cools and hardens it will form igneous rocks. When there is pressure and intense heat on rocks, they form metamorphic rocks.
Aggregate (rocks), sand, and portland cement. And water, initially. That's a typical mix.