only three cycles seem Three explanations suggest themselves (1) Climatic cycles, (2) minor diastrophisms in the Tropic disturbance, (3) great storms and bottom churning in deep waters. Explanation (2) hardly seems probable for such minor changes, while (3) does not explain the source of the sand for some is present in the Hack a Rue Shales. Accordingly explanation (1) appears to have the most value but while the greater or less rainfall may be the underlying explanation it cannot alone be the explanation for the cycles are hardly cyclic enough. On the same way the alternation of the limestone beds seen in the moning may also be explained by the climatic cycle. It may be that on the climatic cycles are superposed other cycles in the variability of the solar kinetic energy = the sun - spot theory. At Slatington we are stopping at Bittress House just opposite the Lehigh Station.