Primary and Secondary Sea Level Index Points. Where information is available on the genesis of the index point it is given. Chronological information is presented as calendar age BP. Confidence is defined as follows: 1. High: Sampled feature with good age and palaeoenvironmental control. 2. Sampled feature with poor or none age and palaeoenvironmental control. 3. Constructed by remote sensing data only, 4. Low: Reasonable without any direct evidence