Species Counterpoint. An Introduction to Species Counterpoint COUNTERPOINT may be briefly defined as the art of combining independent melodies.
In figure 1 the lower melody is harmonized by one a third higher - such an arrangement of the voices could be regarded as counterpoint, but there is little or no independence between the parts; for example there is no dissonance between the voices, and both rise and fall together in parallel. However, the arrangement in figure 1a demonstrates much greater independence between its two voices, with movement in one part while the other halts, divergence in the melodic direction of the parts, and with at least some occurrence of dissonance. In a longer melody the voices could peak at different times - this would also emphasize their independence.
J.J.Fux's Gradus Ad Parnassum is the classic text dealing with species counterpoint and fugue; it presents a set of rules for writing in the style of 16th century vocal composition (i.e. List of chord progressions. MusicalMind.org Ear Training Online.