## 5 Conclusions and Final Remarks  
It was demonstrated that expansive hydration of anhydrite during the weathering of these rocks leads to the creation of peculiar convex landforms characterized by defined sizes and shapes. Such landforms studied in the abandoned gypsum quarry at Dingwall have developed for more than 65 years, counting since the time of anhydrite bedrock exposure, i.e., longer than the growth of hydration forms at the Pisky site and much shorter than at the Walkenried site, where the hydration continues for more than 300 years [52]. At present, the majority of the studied landforms (estimated at about 91%) seem to be in the mature or senile stage of development (Figure 2f). 62% of them have internal proper caves [96; 97], being a unique speleological object known as hydration or swelling caves. Among them is one of the largest hydration caves, measuring 10.7 \(\times\) 6.6 \(\times\) 1.10 m.  
The landforms from Dingwall, similar to the other mentioned sites, are characterized by defined sizes and shapes. The two basic shapes include dome-like, dominating and tepee-like, less frequent; the latter is defined by a sharp crest. In a plan view, the landformsvary from circular through oval to elongated in shape, with length (a) to width (b) ratio rarely exceeding 5:2 (Figure 6). These shapes are an idealized approximation of the real shapes, which are commonly irregular and complex and difficult to define and classify, particularly in the case of \"senile\" forms undergoing destruction. The sizes of the studied landforms are limited. Most commonly, they are 1.8-8.0 m in length (90% of forms). The lower limit of length was not determined precisely, but presumably is a few tens of centimeters. The upper limit is 23 m, and as a rule, the longer the form, the less frequently it occurs. The relative height ranges from 0.33 to 2.09 m and is 0.83 m on average. The frequency distribution of sizes (length, width, relative height) confirms the general rule observed in the dimensions of many landforms characterized by \"large numbers of small values and smaller numbers of large ones\" ([PERSON], 1969) (p. 62). All of the obtained histograms appear to show right-skewed distributions, although the smallest sizes were not documented (Figure 6, Table 2). The size of the hydration landforms depends mainly on the thickness of the detached rock layer--the thicker the layer, the larger the hydration form. The length (a), width (b) and relative height (h\({}_{\rm r}\)) for the majority of forms overall show proportional relations, testifying that the hydration landforms preserve generally the same or very similar shape independent of their sizes. The relations between these basic parameters can be expressed by the following equations: b = 0.67a, h\({}_{\rm r}\) = 0.16a, h\({}_{\rm r}\) = 0.23b; with correlation (Pearson) coefficients (r) of 0.77, 0.75, and 0.63, respectively, indicating moderate correlation. The convexity of hydration landforms was characterized by a b/h\({}_{\rm r}\) ratio--bulge degree. It ranges from 1.82 for the most convex forms to 8.58 for the least convex forms. According to the average value of this parameter, the domed forms are slightly less convex than the tapee-shaped ones. Maximum lateral expansion, measured normally to the approximated crest line of the landforms, provides information on the strain responsible for the creation of their convex shape. Simplifying informs us about the direction of dominating \"forces\" pushing up or buckling the detached layer. Although MLE was most commonly normal or nearly normal to the elongation of the forms (46% of them), quite often, it was parallel to the elongation (29% of forms; Figure 7d,g). It can be concluded that the centers of accelerated greater volume expansion (crystallization of the secondary gypsum) were presumably located at sites near the erected forms, situated as a rule normally to their elongation or, less commonly, along this direction. The development of hydration landforms depends on the structure of the bedrock on which they occur.