The calcite layer and aragonite layers are multi-scale structure , and a small quantity of organic matrix distributes mainly in their grain boundary.
贝壳中的方解石和文石层均呈多级超微结构，微量的有机质在晶界和晶内呈不连续分布。
2
The limestones and sandstones without oil were obviously strong in calcite cementation and grain growing. so they had poor storage property and pore-constructures. and even lost storage capacity.