@gavvet - Amazing find of these rock tools from thousands of years ago and a very relevant and precise analysis of the usage. After your explanation, I could take one more look and realize the cause of chipping. Now, when I visit museums, I will look out for such marks of chipping Something new I learnt today - thanks to you. Upvoted.
I went on am early morning photography and bird outing today to shake off my Monday blues. Have written a blog with collages of some nice birds (made with my original photos). I request you to take a look and let me know your views. Your comments will be eagerly awaited. Thanks