Simplify the following text for a Grade 10 native English-speaking person.
Original: Laurasia included most of the landmasses which make up today 's continents of the northern hemisphere , chiefly Laurentia ( the name given to the North American craton ) , Europe , Baltica , Siberia , Kazakhstan , and China .
Simplified: The name combines the names of Laurentia , the name given to the North American craton , and Eurasia . As suggested by the geologic naming , Laurasia included most of the landmasses which make up today 's continents of the Northern Hemisphere , chiefly Laurentia ( i.e. the core North American continent ) , Baltica , Siberia , Kazakhstania , and the North China and East China cratons .