This data set compiles the raw data used to evaluate the performance of the Goto & Matsubayashi model for continental sedimentary rocks ( Goto & Matsubayashi, 2009). It reports thermal diffusivity (α) and porosity (φ) data for two suites of rock, quartz sandstones of varying porosity and clastic and carbonate lithologies of variable porosity and modal mineralogy. The rock collection involves roughly 120 samples (from boreholes and outcrops) with porosities between 0 and 35%, on which the operability of the Goto & Matsubayashi modified geometric mean model (mGM) was evaluated and quantified. Our study confirms the operability of the mGM for consolidated quartz-rich sandstones and implies a reasonably good performance of this model also for mineralogically more complex sedimentary rocks. This model was also proven to be an appropriate tool to convert thermal diffusivity data obtained on air-saturated samples into such reflecting water-saturated conditions. Altogether, our study suggests that the mGM is suited to model thermal-diffusivity data of all types of sedimentary rock of whatever porosity and chemistry of the pore fluid. The data reported in this data publication are the basis for tables and plots published by Fuchs et al. (2020). Data are provided in tab-delimited text format and described in detail in the associated data description.