Palynofacies, microcharcoal, clay mineralogical and carbon isotope mass spectrometry measurements from the Late Pliensbachian (934 – 918 mbs) of the Mochras core, Cardigan Bay Basin, NW Wales, UK. Data description: This dataset of the Mochras borehole contains palynofacies, microcharcoal, clay mineralogical data, bulk organic carbon-isotopes, TOC and CaCO3 data from the interval 934 – 918 mbs. This dataset extents the previously published dataset (951 – 934 mbs) deposited at: https://doi.org/10.5285/d6b7c567-49f0-44c7-a94c-e82fa17ff98e and discussed in the published paper by Hollaar et al. (2021) https://doi.org/10.1038/s43247-021-00307-3. The dataset is also linked to the XRF dataset https://doi.org/10.5285/c09e9908-6a21-43a8-bc5a-944f9eb8b97e Damaschke et al. (2021) which also covers the study interval of the here deposited dataset of the Mochras core. This dataset covers part of the Upper Margaritatus Zone in the Mochras core and covers the onset of the Late Pliensbachian positive carbon-isotope excursion. This data was collected, interpreted and analysed by Teuntje Hollaar, Claire Belcher, Stephen Hesselbo, and Jean-Fran?ois Deconinck. The dataset was created within the scope of the JET project (Integrated understanding of Early Jurassic Earth system and timescale) - https://gtr.ukri.org/projects?ref=NE%2FN018508%2F1. This project has received funding from the International Continental Scientific Drilling Programme (ICDP) and the UK Natural Environment Research Council (NERC).