This manuscript presents important data (though only through 3 samples) to evaluate the characteristics of organic matter source, hydrocarbon maturity and source rock potential as well as their maturity through estimation of TOC, hydrogen index, oxygen index, production index and T max in the Miocene limestones from the South China Sea. The other significant contribution of this manuscript is evaluation of structural/stratigraphic control on the hydrocarbon seepage. However, I see that two out of three samples have very low TOC and hence the interpretations should be slightly modified and presented in caution (e.g. Type III kerogene, allochthonous/allochthonous source, source rock potential, etc). I recommend its acceptance with minor corrections and the authors should modify this manuscript slightly.

Abstract: The abstract can be shortened by half of it present size and the authors should focus on their findings. It is very elaborative in its present form.

Methodology: It should have information of the sample size and sample locations.

Discussion: The authors should present the interpretations with caution as TOC content is very low and hence the positions in the discriminating diagrams are not very conclusive.

Conclusions: The authors should list the important findings of this research.

Figure 4 (a). Check the fields of classification based on TOC values. TOC<0.5 should be poor and TOC of 1-2% is good.
Figure 4 (b) The low TOC content of two out of three samples plotting them exactly in the boundary between allochthonous/allochthonous sources. It should be interpreted accordingly.
Figure 5 (a) Due to low TOC, the type III kerogene interpretation should be presented with caution.
Figure (c) This figure lacks the sample with OI>200, it has only two samples.

Thank you for incorporating the changes.