Crackly Crust

This loaf of sourdough is delicious and has good holes but why is the crust so jagged?  I preheated the clay oven along with the oven and held it @ 500F for 30.  Then I took off the lid and baked @ 425 for about 15 minutes more.  The dough was pretty sticky.

After 30 minutes @ 500F

Done!