In a combining L district, all regulations shall remain the same as in the R district with which it is combined, except as to the matters hereinafter specified. Every parcel designated on the zoning map as being in a combining A district, as well as every parcel designated thereon as being a combining L district shall be subject to these regulations for an L district, and shall be so shown on any revised zoning map or part thereof. (Prior gen. code § 8-42.1)