What can be brought to a referendum?

 The Grenada Constitution Order  1973

http://www.gov.gd/egov/docs/legislations/constitution/grenada_constitution_order_1973.pdf

39.-(1) Parliamentmay alter any of the provisions of this Constitution or of the Courts Order orsection 3 of the West Indies Associated States (Appeals to Privy Council) Order1967(a) in the manner specified in the following provisions of this section.

(5) A bill to alter thissection, Schedule 1 to this Constitution or any of the provisions of thisConstitution specified in Part I of that Schedule or any of the provisions ofthe Courts Order specified in Part II of that Schedule or section 3 of the WestIndies Associated States (Appeals to Privy Council) Order 1967 shall not besubmitted to the Governor for his assent unless-

a.       there has been an interval of not less than ninety daysbetween the introduction of the bill in the House of Representatives and thebeginning of the proceedings in the House on the second reading of the bill inthat House ;

b. after it has been passedby both Houses of Parliament or, in the case of a bill to which section 48 ofthis Constitution applies, after its rejection by the Senate for the secondtime ; and

c. the bill hasbeen approved on a referendum, held in accordance with such provision as may bemade in that behalf by Parliament, by not less than two-thirds of all the votesvalidly cast on that referendum.