846 LAWS OF MARYLAND. [CH. 286

established by said Commission, no grading of a permanent
nature shall be made, and any such unauthorized grading by
any state, municipal or county officer or employee or any pri-
vate person, is hereby declared to be a misdemeanor.

The Commission shall adopt regulations governing the sub-
division of land within the District. Such regulations may
provide for the proper arrangement of streets in relation to
other existing and planned streets and to the Commission-
general plan, for adequate and convenient open spaces for
traffic, utilities, access of firefighting apparatus, recreation,
light and air, and for the avoidance of congestion of popula-
tion, including minimum width and area of lots.

Such regulations may include provisions as to the extent
and manner in which streets and other ways, curbs, gutters
and sidewalks shall be graded, improved and arranged, and

details of tree planting and other sub-division improvements.
In lieu of the completion of such improvements prior to the
approval of the plat, the Commission may accept a bond with
surety to secure to the Commission the actual construction and
installation of such improvements and developments at a time
and according to specifications fixed by or in accordance with
the regulations of the Commission. The Commission is here-
by granted the power to enforce such bond by all appropriate
legal and equitable remedies.

23. That the zoning of the district may be based upon any
combination of two or more of the purposes described in Sec-
tions 20, 21 and 22 of this Act. The respective District Coun-
cils may, from time to time, amend or change the number,
shape, area or regulation of or within any district or districts;
but no such amendment or change shall become effective un-
less the regulation proposing such amendment or change shall
be first submitted to the Commission for approval, disapproval
or suggestions, and the Commission shall have been allowed a
reasonable time, not less than thirty days, for consideration
and report. Similarly, in the original zoning regulations en-
acted by the District Councils, there shall be no change in or
departure from the plan submitted by the Commission until
and unless such change or departure shall first be submitted
to the Commission for its approval, disapproval or suggestions,
and the Commission shall have been allowed a reasonable time,
not less than thirty days, for consideration and report. Before
any regulation or regulations authorized by this section and
Sections 20, 21 and 22 of this Act may be passed, the District