The examination of method to describe mathematically geological information observed at outcrops is necessary to construct outcrops database. The previous studies showed that the outcrop structure and the stratigraphy at an outcrop composed of unturned sedimentary layers are mathematically expressed in the forms of a structure graph G = (V, R) and a stratigraphic graph S = (V, U^＊), respectively, where V is the set of geological bodies, R is the contact relation and U^＊ is the reflective and transitive closure of the chronological order U. The present study extend the idea to describe the outcrop including igneous rocks and faults. The contact relation between geological bodies x and y is expressed in the term of binary relation xR⁺y; R⁺= {(x, y)| xRy∨xIy∨xFy, x∈V, y∈V}, where xRy indicates that geological units x and y contact each other and x is overlain by y, xIy indicates that x is intruded by an igneous rock y, and xFy indicates that x is cut by a fault y. The information of the contact relation such as conformity, unconformity, intrusion and fault is shown by the label of the arc. Thus we can express the outcrop structure in the form of a stracture graph G = (V, R⁺). As the law of superposition gives an inference rule such that xRy implies xUy and the law of crosscutting gives another rule such that xIy and xFy imply xUy, we obtain a general inference rule such that xR⁺y implies xUy. Using the chronological order U^＊ derived from the contact relation based on the inference rule, we can express the stratigraphic sequence in the forms of a stratigraphic graph S = (V, U^＊) and a labeled Hasse diagram.

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