Thank you for your research on Sange Mariam. I have some of them, a strand made at least 20 years ago and some newer. Technically the rock is called a "coquina", that is, a sedimentary rock with a matrix (a fine mud, dark brown in colour in this case) containing a high percentage of more or less broken shell, mostly from molluscs. In this case the great majority of visible fragments belongs to bivalves. The "teeth" you can see also in your specimens can be due to external ornamentation (lamellae,ribs etc) of the shell seen in cross section, or to the teeth of the hinge line, the area of the shell in which the two valves articulate. Radulae (a sort of tongue with serial teeth) are usually too small to be easily seen without a strong lens or a microscope.
Greetings,
Giorgio