Limestone, chalk, and chert are the geologic expression of the "skeletal" remains of the shells of calcareous and siliceous plankton and protozoa.
The Earth's surface has millions of square kilometers of limestone, chalk, and chert. In some places the strata is thousands of feet thick.
Cliffs of Dover? Yep, a massive, and thick pile of the remains of the shells of plankton and protozoa.
Plankton, foraminifera, diatoms, and protozoa are actually numerous and widespread enough to be buried quickly, and to leave behind vast deposits of rock made from their shells.
But, if you are expecting miles deep remains of T-Rex and triceratops bones, the math, chemistry, and physical laws of nature simply do not support it