Complex sentence: Most designs continued in use throughout the 2nd and 3rd centuries CE. In a 2nd and 3rd century CE variation, the Tutulus type, the circular disc plate was extended upwards to form a cone.
Split into simpler sentences: Most designs continued in use throughout the 2nd and 3rd centuries. In one later variation during this time, the Tutulus type, the circular disc plate was extended upwards to form a cone.