No part or portion of any lot which is determined by the Conservation
Commission to be a coastal or freshwater wetland, as defined by the
Wetlands Protection Act (MGL c. 131, § 40) and the regulations
promulgated thereunder (310 CMR 10.00), shall be used in determining
minimum lot size as required herein, except that this subsection shall
not apply to any lot lawfully laid out by plan or deed duly recorded,
as defined in MGL c. 41, § 81L, prior to the effective date
of this subsection, to any lot shown on a plan endorsed, prior to
the effective date of this subsection, with the words, "Approval under
the Subdivision Control Law not required" or words of similar import,
pursuant to MGL c. 41, § 81P, or to any lot shown on a definitive
plan endorsed with the words "Approved under the Subdivision Control
Law" or words of similar import, pursuant to MGL c. 41, § 81U,
which complied at the time of such recording or endorsement, whichever
is earlier, with all of the minimum area requirements set forth in
the Zoning Bylaw, except for this subsection; provided, however, that
this subsection shall apply to any subdivision under the Subdivision
Control Law, aforesaid, submitted to the Planning Board on or after
the effective date of this subsection.