  We present Washington C, T1 CCD photometry of 21 fields located in the
northern part of the Large Magellanic Cloud (LMC), and spread over a region of
more than 2.52 degrees approximately 6 degrees from the bar. The surveyed areas
were chosen on the basis of their proximity to SL 388 and SL 509, whose fields
showed the presence of a secondary giant clump, observationally detected by
Bica et al. (1998, AJ, 116, 723). From the collected data we found that most of
the observed field CMDs do not show a separate secondary clump, but rather a
continuous vertical structure (VS), which is clearly seen for the first time.
Its position and size are nearly the same throughout the surveyed regions: it
lies below the Red Giant Clump (RGC) and extends from the bottom of the RGC to
approximately 0.45 mag fainter, spanning the bluest color range of the RGC. The
more numerous the VS stars in a field, the larger the number of LMC giants in
the same zone. Our analysis demonstrate that VS stars belong to the LMC and are
most likely the consequence of some kind of evolutionary process in the LMC,
particularly in those LMC regions with a noticeable large giant population. Our
results suggest that in order to trigger the formation of VS stars, there
should be other conditions besides the appropriate age, metallicity, and the
necessary red giant star density. Indeed, stars satisfying the requisites
mentioned above are commonly found throughout the LMC, but the VS phenomenon is
only clearly seen in some isolated regions. Finally, the fact that clump stars
have an intrinsic luminosity dispersion further constrains the use of the clump
magnitude as a reliable distance indicator.
