The bed-thickness of sedimentary beds and its frequency distribution in a geological body have been treated to show a lognormal distribution. In this paper it is discussed on a basis of a model presented by a great Russian mathematician, Prof. Kolmogorov, A.N. who said that a sedimentary bed has a thickness of so-and-so cm, but in some cases, it has a negative thickness. Actually, the presence of a washed -out phenomena will erode the pre-existing sedimentary layer, and sometimes the pre-existing will completely disappear. For such a washed-out bed, Kolmogorov described that it has a negative thickness. In this paper, an example for the Neogene Kakegawa Formation and its bed-thickness is presented, and additionally the bed-thickness of varved diatomite in the Hiruzenbara Formation of Okayama Prefecture is noted as an example of rather accumulative type of sedimentation.

In this time of year of 2018, I have recieved a special prize (called "Distinguished Service Prize") from the authorized committee of the Sedimentological Society of Japan (SSJ), for which I have no word to express my cordial thanks to all of the office members of the society. I am extremely happy to have this prize, and I thought that I should say thanks to all of the students and graduates, members of SSJ. In stead of saying thanks, it will be more fruitful to all of them to write something on the sedimentary geology, particularly based on my own experiences of the studies during my own academic works in these years. Fortunately, I have found my notes each of them being filed, and stored in a study room of my home. They were compiled at the time of my original paper had published, for example, 1957, 1959 and so on. I had read many papers mainly foreign papers written in English or German. Imagine that in 1950’s we have no copymachine or photo-copier, all the information, which should be memorize, had to be hand-written in my notebook. Most of the table, map, figure, were recorded in the notebook. It had been time-comsuming work for the students, and I has been clearly reminiscent of my old days by reading these notes. By referring them, I would like to describe the essential part of my papers published. It will contain the fundamental idea, e.g. of Kolmogorov, or those of German geologists. Topics treated in this paper are exclusively concerning the sedimentary geology; however, related sciences are so wide in their fields covering petrology, mathematics, chemical kinetics and so on. I believe that my notebooks are reminiscent of what I read, and what I thought, at the time of my research works on each subjects described herein.