I found a sea shell in a visit to Latamber in Pakistan (NWFP): https://www.flickr.com/photos/hendry/73369720/
Gemini says "As the crow flies (Straight-line distance): Approximately 900 to 920 kilometers (roughly 560 to 570 miles) directly north of the coast at Karachi"
Maybe a nitpick but Latamber is not directly north of Karachi and it's about 1000 kilometers away (the closest coast is 950 km but not in Karachi). It's easy to see and to measure on a map.
Maybe some geology buffs can correct me, but as I understand it there has been three periods with ocean on top of the crust we call Pakistan today. The Proto-Tethys, Paleo-Tethys, and Tethys Ocean. Many hundreds of millions of years of being ocean.
Because of the Indian subcontinent colliding with the Eurasian plate there's a wide variety of origins for the surface geology in that region.
An incredibly detailed and descriptive map:
https://upload.wikimedia.org/wikipedia/commons/5/52/1964_Pak...