俱舍論頌疏論本 12.18

12.18

此後復有二十中劫名成已住次第而起，謂從風起造器世間，乃至後時有情漸住。此洲人壽經無量歲，至住劫初壽方漸減，從無量劫減至極十年，即名為初一住中劫（已上釋第七第八句）。

After this, there are another twenty intermediate kalpas called the duration after formation, which arise successively. That is to say, from the rising of wind constructing the vessel world up to later when sentient beings gradually abide, the lifespan of humans on this continent spans an immeasurable number of years. Only at the beginning of the kalpa of duration does the lifespan begin to gradually decrease: decreasing from an immeasurable kalpa down to a minimum of ten years is called the very first intermediate kalpa of duration (this concludes the explanation of the seventh and eighth lines).