Great game ... great start ... but after 10h of gameplay no sign of chalk or lime?
Try those seeds as of V 1.12.5:
Seed 0: Spawning right in a Limestone-Area. Once you find your first flint, you have enough cattail, food, wood, clay, peat and of course cobble to get going.
Finding surface ores though is a bit more tedious. But some deposits of browncoal are nearby.
Seed 4: Limestone is the second rock layer at spawn. Lots of wood, food and cattail. I like this seed with setting the environment to hot and humid - have to check for bees spawning, but.
Seed 16: Chalk is the second rock layer. Quite a barren start. Once you find clay, peat or forests, you are leaving the Chalk-Area.
Are there any seeds that you like? For what reason ... what is important for you?
Regards,
Voulxe