Fix logic flaws in the paragraph:
The city of Perth has lost many vennels with the gradual transformation of its medieval centre. Some have survived and are still used: Guard Vennel, Cow Vennel, Baxters Vennel, Fleshers Vennel, Water Vennel and Cutlog Vennel.
The city of Perth has lost many vennels with the gradual transformation of its medieval centre, but some have survived and are still used: Guard Vennel, Cow Vennel, Baxters Vennel, Fleshers Vennel, Water Vennel and Cutlog Vennel.