▁The ▁ve ins ▁of ▁most ▁blue ▁che ese ▁are ▁in ▁fact ▁a ▁dark ▁bl u ish - green . ▁There ▁are ▁several ▁vari eties ▁of ▁che ese ▁which ▁are ▁actually ▁green ▁or ▁pale ▁green ▁in ▁colour . ▁Green ▁che ese ▁vari eties ▁include : ▁ ▁Ch erni ▁Vit ▁- ▁Green ▁che ese ▁from ▁Bulg aria ▁S age ▁Derby ▁che ese ▁Sch ab z iger ▁- ▁Swiss ▁green ▁che ese ▁ ▁Other ▁che eses ▁exist ▁which ▁are ▁wh olly ▁or ▁partly ▁green ▁in ▁colour ▁due ▁to ▁the ▁addition ▁of ▁her bs . ▁ ▁Notes ▁ ▁Category : Che ese <0x0A> </s> ▁The ▁Y iy uan ▁R ong ▁C ave ▁Group ▁() ▁is ▁a ▁cluster ▁of ▁Ord ov ician ▁lim estone ▁c aves ▁in ▁the ▁area ▁under ▁the ▁administration ▁of ▁the ▁city ▁of ▁Z ib o , ▁Sh and ong ▁Province , ▁China . ▁R ong ▁C ave ▁proper ▁( , ▁) ▁is ▁the ▁names ake ▁of ▁the ▁cave ▁group . ▁It ▁is ▁located ▁about ▁ ▁to ▁the ▁north ▁of ▁the ▁town ▁of ▁T umen ▁( ). ▁The ▁cave ▁group ▁contains ▁more ▁than ▁ 4 0 ▁c aves ▁in ▁total ▁and ▁is ▁the ▁largest ▁cluster ▁of ▁lim estone ▁c aves ▁in ▁China ▁north ▁of ▁the ▁Yang t ze ▁River . ▁It ▁covers ▁an ▁area ▁of ▁approximately ▁ 1 0 ▁square ▁kilom eters . ▁Other ▁major ▁c aves ▁in ▁the ▁group ▁are ▁Th ous and - Men ▁C ave ▁( ), ▁Rest ing ▁C ave ▁( ), ▁ ▁Stone - Drag on ▁C ave ▁( ),