▁Mar ble , ▁John ▁Michael ▁Tom lin son , ▁ 1 9 9 6 , ▁ ▁The ▁Gem ▁of ▁the ▁Pe ak , ▁William ▁Adam , ▁ 1 8 4 3 ▁ ▁External ▁links ▁▁▁▁▁ ▁Category : Collections ▁of ▁Derby ▁Museum ▁and ▁Art ▁Gallery ▁Category : Ge ology ▁of ▁Derby shire ▁Category : R ock ▁form ations ▁of ▁England ▁Category : L im estone ▁form ations ▁of ▁the ▁United ▁Kingdom <0x0A> </s> ▁K uro sh iod aph ne ▁fus c ob al te ata ▁ ▁is ▁a ▁species ▁of ▁sea ▁sn ail , ▁a ▁marine ▁g ast rop od ▁m oll usk ▁in ▁the ▁family ▁R aph it om idae . ▁ ▁Description ▁The ▁length ▁of ▁the ▁shell ▁var ies ▁between ▁ 5 ▁mm ▁and ▁ 1 2 ▁mm . ▁ ▁The ▁shell ▁is ▁yellow ish , ▁pale ▁vio let ▁or ▁l il ac ▁towards ▁the ▁a pe x , ▁band ed ▁with ▁light ▁brown , ▁one ▁band ▁at ▁the ▁top ▁of ▁the ▁wh or ls ▁dark er ▁than ▁the ▁rest . ▁The ▁shell ▁contains ▁about ▁ 1 6 ▁rib , ▁crossed ▁by ▁fine ▁li ra e ▁. ▁The ▁outer ▁lip ▁is ▁thick ened ▁within ▁and ▁exterior ly , ▁thin ▁at ▁the ▁extreme ▁edge , ▁smooth ▁interior ly . ▁The ▁small ▁sin us ▁is ▁s ut ural . ▁ ▁The ▁shell ▁contains ▁ 9 ▁? ▁wh or ls ▁( ape x ▁broken ), ▁ob liqu ely ▁s lop ing ▁at ▁the ▁upper ▁part , ▁and ▁slightly ▁convex ▁at ▁the ▁sides . ▁They ▁are