Complex sentence: The ocean began to shrink during the Late Silurian, when North China, and South China moved away from Gondwana and headed north, and during Late Devonian, the microcontinent of Kazakhstania collided with Siberia, shrinking the ocean further.
Split into simpler sentences: The ocean began to shrink during the Late Silurian, when North China, and South China moved away from Gondwana and headed north, and during Late Devonian. The microcontinent of Kazakhstania collided with Siberia, shrinking the ocean further.