A magnitude-limited photographic survey of relative proper-motion components and B, V photometry of 1.3x10^6^ stars brighter than apparent B magnitude 14.5+/-0.5 in the fourth Galactic quadrant is converted into a distance-limited survey of 3.26x10^5^ stars up to a distance of 500pc. A streaming motion of 13.5+/-0.5 km/s is detected in 4.1x10^4^ Population I stellar candidates with an orbital perigalactic center located at 6.8<=R<=7.2kpc, with a Sun location Rsol=8.5 kpc. A density perturbation of about 0.1M{sun}/pc^3^ in the Galactic field potential at Ro~6.8kpc is interpreted as resulting from the density wave connected with the Sagittarius-Carina spiral arm. A set of 1.4x10^4^ stars of mass about 1.5+/-0.75 M{sun} identify a pitch angle of 10+/-1{deg} and a migration time from the Sagittarius spiral arm into the greater solar neighborhood of about 35Myr.