FIGURE 8. Three-dimensional reconstruction of the lobe of the phycosiphoniform burrow from Rosario Formation, Mexico. 8.1. The longer arm of the lobe descends gently downward for about 30% of the lobe length and is inclined in about 11° to the bedding plane. Then in about next 30% of lobe length both arms continue more or less parallel to the stratification in order to incline in 24 -25° downward to the sediment. 8.2. In about last 15% of lobe length the arms incline for further 15-19% each in opposite directions (upward and downward) and then direct back to create the apex of the lobe (so in the last part of formed loop the arms are the most distant from each other before they connect in the apex ). 8.3. Whole lobe bent in the horizontal direction along a half-ellipse of with an aspect ratio of 2.4. 8.4. The halo can be several times thicker than the burrow core.