The mid-Ordovician noticed the very first cephalopods with septa powerful enough to manage Together with the pressures related to further water, and will inhabit depths better than a hundred200 m.[139] The route of shell coiling would prove to generally here be vital to the longer term accomplishment of the lineages; endogastric coiling would only allow large measurement to be attained by using a straight shell, whereas exogastric coiling to begin with rather