(a) The county treasurer shall divide the funds received by the treasurer’s office into three classes. The treasurer shall appropriate the money in each class of funds to the payment of the claims registered in the corresponding class of claims.
(b) The classes of funds consist of:
(1) jury fees, money received from the sale of estrays, and occupation taxes;
(2) money received under the provisions of a road and bridge law, including penalties recovered from railroads for the failure to repair crossings, and all fines and forfeitures; and
(3) other money received by the treasurer’s office that is not otherwise appropriated by this section or by the commissioners court.

(c) The commissioners court, as it considers proper, may require other accounts to be kept, creating other classes of funds. The court may require scrip to be issued against those accounts and to be registered accordingly.
(d) The commissioners court by order may transfer money on hand from one fund to another as it considers necessary, but amounts that belong to the first class of funds may not be transferred from the payment of claims registered in that class unless there is an excess amount in that class.