Hi Heather!
OK, GeoCART is also on Lemon64.
This GeoCart is version 1.0 named by me - this cartridge was designed only for me and no one more exist.
I wanted to have it all in one as RAM expansion - this is reason why works in native mode of C128.
Incl. GeoRAM 512K with possible switch to 128K RAMCart with 256K FlashROM and also RTC backuped by battery...
Reason why was one designed: GeoAction works only in 64 mode of C128 'cause it has ID of C64 cartridge... and I wanted only expand RAM for test both solutions - GeoRAM and RAMCart with real-time-clock... Now I have not reson use any of these solutions - GeoRAM is hard possible to use than REU and RAMCart can be maximally 128K... and I own 1,5MB 1764 expanded REU and SuperCPU128 with 16MB RAM, so after wrong work with GeoRAM and limit of RAMCart - I decided to sell it. But GeoRAM is good for GEOS users - and I'm not fan of GEOS...
Miro